Detection of mosaicism for 46,X,i(Y) (q10) in the blood lymphocytes in a phenotypically normal male neonate with prenatally detected 45,X/46, XY at amniocentesis and cytogenetic discrepancy in various tissues

ObjectiveWe present detection of mosaicism for 46,X,i(Y) (q10) in the blood lymphocytes in a phenotypically normal male neonate with prenatally detected 45,X/46, XY at amniocentesis and cytogenetic discrepancy in various tissues.Case reportA 35-year-old, gravida 2, para 1, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 45,X [8]/46,XY [15]. Simultaneous array comparative genomic hybridization (aCGH) on uncultured amniocytes revealed the result of arr (Y) × 0–1 with 25.493-Mb mosaic deletion of chromosome Yp11.31-q11.23. Prenatal ultrasound findings were unremarkable. The fetus had normal male external genitalia on fetal ultrasound. Following genetic counseling, the pregnancy was carried to 38 weeks of gestation, and a phenotypically normal male baby was delivered without any abnormalities of the male external genitalia. The cord blood had a karyotypes of 46,X,i(Y) (q10)[8]/45,X[3]/46,XY [29], and placenta had a karyotypes of 45,X [25]/46,X,i(Y) (q10)[7]/46,XY [8]. When follow-up at age two months, the neonate was normal in development. The peripheral blood had a karyotypes of 46,X,i(Y) (q10)[8]/45,X[5]/46,XY [27]. Interphase fluorescence in situ hybridization (FISH) analysis on 101 buccal mucosal cells showed normal X and Y signals in 101/101 cells.ConclusionFetuses with 45,X/46, XY at amniocentesis can be associated with mosaicism for 46,X,i(Y) (q10) in the blood lymphocytes, cytogenetic discrepancy in various tissues and a favorable outcome.     

High-level mosaicism for 45,X in 45,X/46, XY at amniocentesis in a pregnancy with a favorable fetal outcome and cytogenetic discrepancy in various tissues

ObjectiveWe present prenatal diagnosis of high-level mosaicism for 45,X by amniocentesis in a pregnancy with a favorable fetal outcome.Case reportA 35-year-old, gravida 2, para 1, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 45,X[13]/46,XY[11]. Simultaneous array comparative genomic hybridization (aCGH) on uncultured amniocytes revealed the result of Yp11.3q11.21 × 0–1 [0.1], Yq11.21q11.23 × 0–1 [0.6]. At 19 weeks of gestation, she underwent the second amniocentesis which revealed a karyotype of 45,X[13]/46,XY[12], and aCGH and multiplex ligation-dependent probe amplification (MLPA) on uncultured amniocytes showed 37% mosaicism for Y-deleted cells. At 28 weeks of gestation, she underwent the third amniocentesis which revealed a karyotype of 45,X[25]/46,XY[25], and aCGH on uncultured amniocytes revealed the result of Yq11.21q11.23 × 0.5, Yq11.23q12 × 0.7. Interphase fluorescence in situ hybridization (FISH) analysis on uncultured amniocytes revealed that 16.67% (20/120 cells) were Y-deleted cells. The parental karyortypes and prenatal ultrasound were normal. At 37 weeks of gestation, a 2707-g phenotypically normal male baby was delivered with normal male external genitalia. The karyotypes of cord blood, umbilical cord and placenta were 45,X[25]/46,XY[15], 45,X[18]/46,XY[22] and 45,X[25]/46,XY[15], respectively. When follow-up at age five months, the neonate was normal in external genitalia and physical development. The peripheral blood had a karyotype of 45,X[29]/46,XY[11], and FISH analysis on 100 buccal mucosal cells showed no abnormal signals. When follow-up at age 11 months, the neonate was physically normal, and the peripheral blood had a karyotype of 45,X[17]/46,XY[23].ConclusionHigh-level mosaicism for 45,X in 45,X/46, XY at amniocentesis can be associated with a favorable fetal outcome despite the presence of cytogenetic discrepancy in various tissues.     

High-level mosaicism for 45,X in 45,X/46,XX at amniocentesis in a pregnancy with a favorable outcome and postnatal progressive decrease of the 45,X cell line

ObjectiveWe present prenatal diagnosis of high-level mosaicism for 45,X in 45,X/46,XX at amniocentesis in a pregnancy with a favorable outcome and postnatal progressive decrease of the 45,X cell line.Case reportA 32-year-old, gravida 2, para 1, woman underwent amniocentesis at 17 weeks of gestation because of the abnormal first-trimester maternal serum screening result indicating a 1/34 risk for Down syndrome. Amniocentesis revealed a karyotype of 45,X[27]/46,XX[15]. Simultaneous array comparative genomic hybridization (aCGH) on uncultured amniocytes revealed 12% mosaicism for monosomy X. Prenatal ultrasound was normal. The pregnancy was carried to term, and a 2780-g phenotypically normal female baby was delivered. The cord blood had a karyotype of 45,X[12]/46,XX[28]. At age one month, the peripheral blood had a karyotype of 45,X[13]/46,XX[27]. Interphase fluorescence in situ hybridization (FISH) analysis on the buccal mucosal cells revealed 2% (2/102 cells) mosaicism for monosomy X, compared with 1% (1/100 cells) in the normal control. When follow-up at age one year, she was doing well with normal physical and psychomotor development. Her body weight was 9.9 Kg (50th – 85th centile), and her body height was 75 cm (50th – 85th centile). The peripheral blood had a karyotype of 45,X[4]/46,XY[36].ConclusionHigh-level mosaicism for 45,X in 45,X/46,XX at amniocentesis can be associated with a favorable outcome and postnatal progressive decrease of the 45,X cell line.     

Mosaic 45,X/46, XX at amniocentesis with high-level mosaicism for 45,X in a pregnancy with a favorable fetal outcome and postnatal decrease of the 45,X cell line

ObjectiveWe present mosaic 45,X/46, XX at amniocentesis with high-level mosaicism for 45,X in a pregnancy with a favorable fetal outcome and postnatal decrease of the 45,X cell line.Case reportA 20-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation because of the non-invasive prenatal testing (NIPT) result of −4.82 Z score in sex chromosome at 12 weeks of gestation suggestive of Turner syndrome in the fetus. Amniocentesis revealed a karyotype of 45,X [18]/46,XX [15], and simultaneous multiplex ligation-dependent probe amplification (MLPA) on the DNA extracted from uncultured amniocytes showed mosaic Turner syndrome. Prenatal ultrasound and parental karyotypes were normal. She was referred for genetic counseling at 24 weeks of gestation, and continuing pregnancy was encouraged. At 39 weeks of gestation, a 2550-g phenotypically normal female baby was delivered. The karyotypes of cord blood, umbilical cord and placenta were 45,X [24]/46,XX [16], 45,X [23]/46,XX [17] and 45,X [28]/46,X,del(X) (q23)[12], respectively. When follow-up at age two months, the neonate was phenotypically normal in development. The peripheral blood had a karyotypes of 45,X [16]/46,XX [24]. Interphase fluorescence in situ hybridization (FISH) analysis on 103 buccal mucosal cells showed normal disomy X signals in all cells.ConclusionHigh-level mosaicism for 45,X in 45,X/46, XX at amniocentesis can be associated with a favorable fetal outcome, cytogenetic discrepancy in various tissues, and postnatal decrease of the 45,X cell line.     

Progressive increase of the mosaic level for 45,X in 45,X/46, XX at different amniocenteses and postnatal progressive decrease of the 45,X cell line in a mosaic 45,X/46, XX fetus with a favorable outcome

ObjectiveWe present progressive increase of the mosaic level for 45,X in 45,X/46, XX at different amniocenteses and postnatal progressive decrease of the 45,X cell line in a mosaic 45,X/46, XX fetus with a favorable outcome.Case reportA 35-year-old, primigravid woman underwent amniocentesis at 16 weeks of gestation because of the advanced maternal age. Amniocentesis revealed a karyotype of 45,X [6]/46,XX [14]. Among 20 colonies of cultured amniocytes, six colonies had a karyotype of 45,X, whereas the other 14 colonies had a karyotype of 46,XX. Simultaneous array comparative genomic hybridization (aCGH) on uncultured amniocytes revealed the result of arr [GRCh37] (X) × 1 [0.42] (1–22) × 2. Prenatal ultrasound findings were unremarkable. Repeat amniocentesis at 33 weeks of gestation revealed a karyotype of 45,X [13]/46,XX [7]. Among 20 colonies of cultured amniocytes, 13 colonies had a karyotype of 45,X, whereas the other seven colonies had a karyotype of 46,XX. Simultaneous interphase fluorescence in situ hybridization (FISH) analysis on 100 uncultured amniocytes revealed that 44 cells had monosomy X consistent with 44% mosaicism for 45,X, whereas the rest cells had disomy X. At 38 weeks of gestation, a 2675-g phenotypically normal female baby was delivered. The karyotypes of cord blood, umbilical cord and placenta were 45,X [12]/46,XX [28], 45,X [12]/46,XX [28] and 46,XX [40/40], respectively. When follow-up at age three months, the neonate was normal in development. The karyotypes of peripheral blood was 45,X [4]/46,XX [36], and interphase FISH analysis on 100 buccal mucosal cells showed monosomy X in 11 cells consistent with 11% mosaicism for 45,X, whereas the rest cells had disomy X.ConclusionProgressive increase of the mosaic level for 45,X in 45,X/46, XX at different amniocenteses can be associated with a favorable outcome and postnatal progressive decrease of the 45,X cell line.     

Mosaic tetrasomy 9p at amniocentesis in a pregnancy associated with a favorable fetal outcome,perinatal progressive decrease of the aneuploid cell line and cytogenetic discrepancy in various tissues

ObjectiveWe present mosaic tetrasomy 9p at amniocentesis in a pregnancy associated with a favorable fetal outcome, perinatal progressive decrease of the aneuploid cell line and cytogenetic discrepancy in various tissue.Case reportA 33-year-old primigravid woman underwent elective amniocentesis at 18 weeks of gestation because of anxiety, and the karyotype of cultured amniocytes was 47,XX,+i (9) (p10)[20]/46,XX [55]. Cordocentesis was performed at 20 weeks of gestation, and the karyotype of cord blood was 47,XX,+i (9) (p10)[7]/46,XX [15]. She was referred for genetic counseling at 23 weeks of gestation, and repeat amniocentesis revealed a karyotype of 47,XX,+i (9) (p10)[1]/46,XX [16] with seven cells in one colony having tetrasomy 9p in cultured amniocytes, and in uncultured amniocytes, quantitative fluorescence polymerase chain reaction (QF-PCR) analysis excluded uniparental disomy (UPD) 9 and determined paternal origin of the extra i (9p), array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed arr 9p24.3p13.1 × 3.0 consistent with 50% mosaicism for tetrasomy 9p, and interphase fluorescence in situ hybridization (FISH) on uncultured amniocytes showed 22.6% (12/53 cells) mosaicism for tetrasomy 9p. A third amniocentesis at 27 weeks of gestation revealed a karyotype of 46, XX (10/10 colonies) in cultured amniocytes, and interphase FISH analysis on uncultured amniocytes revealed 20% (20/100 cells) mosaicism for tetrasomy 9p. The parental karyotypes and prenatal ultrasound were normal. At 39 weeks of gestation, a phenotypically normal 3388-g female baby was delivered. The karyotypes of cord blood, umbilical cord and placenta were 47,XX,+idic (9) (q12)[19]/46,XX [21] or 47,XX,+idic (9) (pter→q12:q12→pter)[19]/46,XX [21], 47,XX,+idic (9) (q12)[1]/46,XX [39] and 47,XX,+idic (9) (q12)[4]/46,XX [36], respectively. When follow-up at age two months, the neonate was phenotypically normal, the peripheral blood had a karyotype of 47,XX,+idic (9) (q12)[18]/46,XX [22], and interphase FISH analysis on 100 buccal mucosal cells revealed 1% (1/100 cells) mosaicism for tetrasomy 9p. When follow-up at age seven months, the neonate was phenotypically normal, and the peripheral blood had a karyotype of 47,XX,+idic(9)(q12)[14]/46,XX[26].ConclusionMosaic tetrasomy 9p at amniocentesis can be a transient and benign condition, and can be associated with a favorable fetal outcome and perinatal progressive decrease of the aneuploid cell line and cytogenetic discrepancy in various tissue.     

Prenatal diagnosis and molecular cytogenetic characterization of mosaicism for r(13), monosomy 13 and idic r(13) by amniocentesis

ObjectiveWe present prenatal diagnosis and molecular cytogenetic characterization of mosaicism for ring chromosome 13 [r(13)], monosomy 13 and isodicentric ring chromosome 13 [idic r(13)] by amniocentesis.Case reportA 24-year-old woman underwent amniocentesis at 23 weeks of gestation because of intrauterine growth restriction (IUGR) in the fetus. Amniocentesis revealed a karyotype of 46,XY,r(13)[23]/45,XY,-13[10]/46,XY,idic r(13)[2]. The parental karyotypes were normal. Array comparative genomic hybridization (aCGH) on cultured amniocytes revealed the result of arr 13q11q31.3 (19,436,286–92,284,309) × 1.85, arr 13q31.3q34 (92,288,514–115,107,733) × 1 [GRCh37 (hg19)], indicating a 22.82-Mb 13q31.3-q34 deletion and a 15–20% mosaicism for 13q11-q31.3 deletion. The pregnancy was subsequently terminated, and a malformed fetus was delivered with facial dysmorphism. The placental tissues had a karyotype of 46,XY,r(13)[18]/46,XY,-13,+mar[14]/45,XY,-13[8]. Polymorphic DNA marker analysis confirmed a maternal origin of the 13q deletion.ConclusionFetus with mosaic r(13), monosomy 13 and idic r(13) may present IUGR on prenatal ultrasound, and fetoplacental cytogenetic discrepancy may exist under such a circumstance.     

Mosaic Xq duplication,or 46,X,der(X)dup(X)(q22.1q22.2)dup(X)(q25q22.3)/ 46,XX at amniocentesis in a pregnancy with a favorable outcome

ObjectiveWe present mosaic Xq duplication, or 46,X,der(X)dup(X)(q22.1q22.2)dup(X)(q25q22.3)/46,XX at amniocentesis in a pregnancy with a favorable outcome.Case ReportA 40-year-old woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a result of 46,X,der(X)dup(X)(q22.1q22.2)dup(X)(q25q22.3)[7]/46,XX[20]. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed the result of arr (1–22, X) × 2. Cytogenetic analysis on maternal blood revealed a karyotype of 46,XX. At 22 weeks of gestation, she underwent repeat amniocentesis which revealed a karyotype of 46,XX in 22/22 colonies of cultured amniocytes and an aCGH result of (1–22, X) × 2 in the uncultured amniocytes. Prenatal ultrasound findings were unremarkable. The parents decided to continue the pregnancy, and a healthy female baby was delivered at 39 weeks of gestation with a body weight of 3510 g and a body length of 49 cm. The cord blood had a karyotype of 46,X,der(X)dup(X)(q22.1q22.2)dup(X)(q25q22.3)[3]/46,XX[37]. At age two months, interphase fluorescence in situ hybridization (FISH) analysis on buccal mucosal cells showed Xq duplication signals in 1.25% (1/80 cells), compared with 0% (0/90 cells) in the normal control. At age nine months, the neonate had normal physical and psychomotor development. Her body weight was 9.6 Kg (85th - 97th centile), and body length was 72 cm (50th - 85th centile). Cytogenetic analysis of peripheral blood revealed a karyotype of 46,X,der(X)dup(X) (q22.1q22.2)dup(X)(q25q22.3)[1]/46,XX[39]. Interphase FISH analysis on 100 buccal mucosal cells revealed no abnormal signal.ConclusionIn case of mosaicism for an Xq duplication with a normal euploid cell line at amniocentesis, the in-vitro culture process of amniocytes may cause over-estimation of the mosaic level for the aberrant chromosome because of culture artifacts, and the abnormal cell line can decline after birth.     

Cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes in mosaic 46,XX,dup(9)(q22.3q34.1)/46,XX at amniocentesis in a pregnancy with a favorable outcome

ObjectiveWe present our observation of cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes in mosaic dup(9)(q22.3q34.1) at amniocentesis in a pregnancy with a favorable outcome.Case reportA 37-year-old, gravida 4, para 0, woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XX, dup(9)(q22.3q34.1)[8]/46,XX[16]. Prenatal ultrasound findings were unremarkable. She was referred for genetic counseling, and repeat amniocentesis was performed at 21 weeks of gestation, which revealed a karyotype of 46,XX,dup(9)(q22.3q34.1)[7]/46,XX[25]. Simultaneous array comparative genomic hybridization (aCGH) on the DNA extracted from uncultured amniocytes revealed no genomic imbalance, or arr (1–22,X) × 2. Interphase fluorescence in situ hybridization (FISH) analysis on 105 uncultured amniocytes detected only one cell with the dup 9q signal with a mosaic dup 9q level of 1%, compared with 0% in normal control. At 37 weeks of gestation, a 2640-g female baby was delivered with no phenotypic abnormality. The cord blood had a karyotype of 46,XX,dup(9) (q22.3q34.1)[4]/46,XX[36], the umbilical cord had a karyotype of 46,XX,dup(9) (q22.3q34.1)[2]/46,XX[38], and the placenta had a karyotype of 46,XX. aCGH analysis on cord blood revealed no genomic imbalance. At age 2½ months, the baby was doing well, the peripheral blood of the baby had a karyotype of 46,XX,dup(9) (q22.3q34.1)[4]/46,XX[36], and interphase FISH analysis on buccal mucosal cells revealed no dup 9q signal in 100 buccal mucosal cells.ConclusionCytogenetic discrepancy may occur between cultured amniocytes and uncultured amniocytes in mosaic dup(9) (q22.3q34.1). Molecular cytogenetic analysis on uncultured amniocytes is useful for rapid distinguishing pseudomosaicism from true mosaicism under such a circumstance.     

Perinatal cytogenetic discrepancy in a pregnancy with mosaic 45,X/46, XY at amniocentesis and a favorable outcome

ObjectiveWe present perinatal cytogenetic discrepancy in a pregnancy with mosaic 45,X/46, XY at amniocentesis and a favorable outcome.Case reportA 38-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 45,X[2]/46,XY[6]. Level II ultrasound at 20 weeks of gestation was unremarkable, and the fetus had normal male external genitalia. Following genetic counseling, the woman decided to continue the pregnancy. At 39 weeks of gestation, a healthy male baby was delivered with a body weight of 3410 g and a body length of 54.5 cm. The male external genital organs were normal. The cord blood had a karyotype of 46, XY (40/40 cells). The umbilical cord had a karyotype of 45,X[1]/46,XY[39]. During follow-up at age one month, his body weight was 4.4 Kg (15th-50th centile), and his body length was 56 cm (50th-85th centile). The infant was doing well. Interphase fluorescence in situ hybridization analysis on 100 buccal mucosal cells revealed no abnormal Y-deletion cell, and all cells contained one Y signal.ConclusionPerinatal cytogenetic discrepancy may occur in the pregnancy with mosaic 45,X/46, XY at amniocentesis.     

Mosaicism for Robertsonian jumping translocation at amniocentesis: 45,XY,der(15;22)(q10;q10)mat/46,XY,i(15)(q10)/46,XY,genetic counseling,prenatal diagnosis and postnatal follow-up in a pregnancy with a favorable fetal outcome

ObjectiveWe present genetic counseling, prenatal diagnosis and postnatal follow-up of 45,XY,der(15;22)(q10;q10)mat/46,XY,i(15)(q10)/46,XY at amniocentesis in a pregnancy with a favorable fetal outcome.Case reportA 27-year-old, primigravid woman underwent amniocentesis at 19 weeks of gestation because increased nuchal translucency thickness, and the result was 45,XY,der(15;22)(q10;q10)[29]/46,XY,i(15)(q10)[3]/46,XY[5]. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed arr (1–22) × 2, (X,Y) × 1. The maternal karyotype was 45,XX,der(15;22)(q10;q10), and the paternal karyotype was 46,XY. She was referred for genetic counseling, and repeat amniocentesis performed at 23 weeks of gestation revealed 45,XY,der(15;22)(q10;q10)mat[23]/45,XY,-22[2]. aCGH analysis on uncultured amniocytes detected no genomic imbalance, and polymorphic DNA marker analysis excluded uniparental disomy (UPD) 15. Fluorescence in situ hybridization (FISH) analysis using the chromosome 15q specific probe and the chromosome 22q specific probe detected three 15q signals in 4/104 cells (3.8%). The woman was advised to continue the pregnancy, and, a 3186-g phenotypically normal male baby was delivered at 38 weeks of gestation. The umbilical cord had a karyotype of 45,XY,der(15;22)(q10;q10) (40/40 cells). When follow-up at age seven months, the neonate was normal in development, the peripheral blood had a karyotype of 45,XY,der(15;22)(q10;q10) (40/40 cells), and the buccal mucosal cells had normal signals in all 100 cells.ConclusionsMosaicism for Robertsonian jumping translocations at amniocentesis can be a transient condition and can be associated with a familial Robertsonian translocation and a favorable fetal outcome. Prenatal diagnosis of a Robertsonian jumping translocation involving chromosome 15 should include UPD 15 testing to exclude UPD 15.     

Mosaic 46,XY,der(15)t(6;15)(q25.1;p12)/46,XY at amniocentesis in a pregnancy associated with a favorable fetal outcome and postnatal decrease of the aneuploid cell line with the unbalanced translocation

ObjectiveWe present mosaic 46,XY,der(15)t(6;15)(q25.1;p12)/46,XY at amniocentesis in a pregnancy associated with a favorable fetal outcome and postnatal decrease of the aneuploid cell line with the unbalanced translocation.Case reportA 34-year-old primigravid woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XY,add(15)(p12)[17]/46,XY[5]. A second amniocentesis at 19 weeks of gestation revealed a karyotype of 46,XY,der(15)t(6;15)(q25.1;p12)[12]/46,XY[8], and array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed arr arr 6q25.1q27×2-3 with 40% mosaic level. She was referred for genetic counseling. Prenatal ultrasound and the parental karyotypes were normal. A third amniocentesis at 24 weeks of gestation revealed a karyotype of 46,XY,der(15)t(6;15)(q25.1;p12)[23]/46,XY[1], and in uncultured amniocytes, aCGH analysis revealed arr 6q25.1q27×2.5, interphase fluorescence in situ hybridization (FISH) revealed 51% mosaicism (51/100 cells) for partial trisomy 6q and quantitative fluorescence polymerase chain reaction (QF-PCR) analysis determined maternal origin of the aberrant chromosome and excluded uniparental disomy (UPD) 15 and UPD 6. A fourth amniocentesis at 27 weeks of gestation revealed a karyotype of 46,XY,der(15)t(6;15)(q25.1;p12)[21]/46,XY[5], and in uncultured amniocytes, aCGH analysis revealed arr 6q25.1q27×2.46, and interphase FISH revealed 35% mosaicism (35/100 cells) for partial trisomy 6q. At 39 weeks of gestation, a healthy 3028-g male baby was delivered without any phenotypic abnormality. The karyotypes of cord blood, umbilical cord and placenta were 46,XY,der(15)t(6;15)(q25.1;p12)[2]/46,XY,der(15)t(6;15)(q25.1;p12)[29]/46,XY[11] and 46,XY, respectively. When follow-up at age one month, the neonate was phenotypically normal, the peripheral blood had a karyotype of 46,XY (40/40 cells), and FISH analysis on 105 buccal mucosal cells detected five cells with partial trisomy 6q compared with 2% mosaicism (2/100 cells) in the normal control.ConclusionMosaicism for an unbalanced translocation with a normal cell line without UPD at amniocentesis can be a transient and benign condition, and can be associated with a favorable fetal outcome and postnatal decrease of the aneuploid cell line.     

Mosaic 46,XY,dup(14) (q12q22.3)/46, XY at amniocentesis in a pregnancy associated with a favorable fetal outcome and cytogenetic discrepancy in various tissues

ObjectiveWe present mosaic 46,XY,dup (14) (q12q22.3)/46, XY at amniocentesis in a pregnancy associated with a favorable fetal outcome and cytogenetic discrepancy in various tissues.Case reportA 41-year-old, primigravid woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. This pregnancy was conceived by in vitro fertilization and embryo transfer. Cytogenetic analysis on cultured amniocytes revealed a karyotype of 46,XY, dup (14) (q12q22.3)[7]/46,XY [13], and simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed arr 14q12q22.3 × 2–3 with 25% mosaicism for partial 14q duplication. She was referred for genetic counseling. Prenatal ultrasound and parental karyotypes were normal. Repeat amniocentesis at 22 weeks of gestation revealed a karyotype of 46,XY,dup (14) (q12q22.3)[6]/46,XY [14], and in uncultured amniocytes, quantitative fluorescence polymerase chain reaction (QF-PCR) analysis excluded uniparental disomy (UPD) 14, aCGH revealed arr 14q12q22.3 × 2.3 with 30% mosaicism for dup (14) (q12q22.3), and interphase fluorescence in situ hybridization (FISH) showed 19.4% (24/124 cells) mosaicism for partial 14q duplication. She was encouraged to continue the pregnancy, and a 2450-g phenotypically normal male baby was delivered at 40 weeks of gestation. The karyotypes of cord blood, umbilical cord and placenta were 46,XY,dup (14) (q12q22.3)[14]/46,XY [26], 46,XY,dup (14) (q12q22.3)[7]/46,XY [33] and 46,XY,dup (14) (q12q22.3)[3]/46,XY [37], respectively. When follow-up at age four months, the neonate was phenotypically normal. The karyotype of peripheral blood was 46,XY,dup (14) (q12q22.3)[27]/46,XY [13], and interphase FISH analysis on 105 buccal mucosal cells detected partial 14q duplication signals in 5 cells (4.8% mosaicism). When follow-up at age nine months, the neonate was phenotypically normal. The karyotype of peripheral blood was 46,XY,dup (14) (q12q22.3)[25]/46,XY [15].ConclusionMosaic dup (14) (q12q22.3) with a normal cell line at amniocentesis may be a benign condition, and can be associated with a favorable fetal outcome and cytogenetic discrepancy in various tissues.     

45,X/46,XX at amniocentesis associated with cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes and in different amniocenteses and a favorable fetal outcome with a normal karyotype at birth

ObjectiveWe present 45,X/46,XX at amniocentesis associated with cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes and in different amniocenteses and a favorable fetal outcome with a normal karyotype at birth.Case reportA 35-year-old, gravida 3, para 2, woman underwent amniocentesis at 20 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 45,X[11]/46,XX[108], consistent with 9.2% mosaicism for 45,X. Prenatal ultrasound findings were unremarkable. She was referred for genetic counseling at 25 weeks of gestation, and repeat amniocentesis at 26 weeks of gestation revealed a karyotype of 45,X[4]/46,XX[16], consistent with 20% mosaicism for 45,X. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes using SurePrint G3 Unrestricted CGH ISCA v2, 8 × 60K (Agilent Technologies, Santa Clara, CA, USA) revealed arr (1–22, X) × 2, Y × 0 with no genomic imbalance. The woman was advised to continue pregnancy, and at 38 weeks of gestation, a healthy 3140-g female baby was delivered with no phenotypic abnormalities. The cord blood had a karyotype of 46,XX (40/40 cells). When follow-up at age two months, the neonate had normal development and a normal karyotype.ConclusionConfirmation of 45,X/46,XX at amniocentesis should include conventional cytogenetic analysis and karyotyping on cultured amniocytes, and sole molecular analysis on uncultured amniocytes may miss the diagnosis of 45,X/46,XX.     

Prenatal diagnosis of recurrent mosaic ring chromosome 13 of maternal origin

ObjectiveWe present prenatal diagnosis of recurrent mosaic ring chromosome 13 [r(13)] of maternal origin.Case ReportA 27-year-old woman underwent amniocentesis at 17 weeks of gestation because of a past history of fetal abnormality caused by mosaic r(13) in the previous fetus associated with fetal intrauterine growth restriction (IUGR), a karyotype of 46,XY,r(13)[23]/45,XY,-13[10]/46,XY,idic r(13)[2] and a maternal origin of abnormal r(13). The parental karyotypes were normal. During this pregnancy, amniocentesis revealed a karyotype of 46,XX,r(13)[12]/45,XX,-13[8] and a 22.80-Mb deletion of chromosome 13q31.3-q34. The pregnancy was subsequently terminated, and a malformed fetus was delivered with craniofacial dysmorphism. Repeat amniocentesis revealed a karyotype of 46,XX,r(13)(p11.1q31)[18]/45,XX,-13[12]. The placenta had a karyotype of 46,XX,r(13)(p11.1q31)[27]/45,XY,-13[13]. Polymorphic DNA marker analysis using the DNA derived from the parental bloods and umbilical cord confirmed a maternal origin of the abnormal r(13).ConclusionPrenatal diagnosis of mosaic r(13) in consecutive pregnancies should raise a suspicion of parental gonadal mosaicism, and polymorphic DNA marker analysis is useful for determination of the parental origin of recurrent aneuploidy under such a circumstance.     

Prenatal diagnosis of mosaicism for double aneuploidy of 47,XXY and trisomy 7 (48,XXY,+7) at amniocentesis in a pregnancy with a favorable outcome

ObjectiveWe present prenatal diagnosis of mosaicism for double aneuploidy of 47, XXY and trisomy 7 (48,XXY,+7) at amniocentesis in a pregnancy with a favorable outcome.Case reportA 33-year-old woman underwent amniocentesis at 17 weeks of gestation because of an increased risk for Down syndrome in maternal serum screening. Amniocentesis revealed a karyotype of 48,XXY,+7[8]/46,XY[16]. Simultaneous array comparative genomic hybridization (aCGH) analysis on uncultured amniocytes revealed the result of arr [GRCh37] (7) × 3 [0.54], (X) × 2 [0.52], (Y) × 1, compatible with trisomy 7 mosaicism and Klinefelter syndrome mosaicism. The parental karyotypes and prenatal ultrasound findings were normal. Repeat amniocentesis performed at 23 weeks of gestation revealed a karyotype of 48,XXY,+7[13]/46,XY[7]. Simultaneous molecular cytogenetic analyses on uncultured amniocytes revealed 30% mosaicism for 48,XXY,+7 by aCGH and 37% (37/100 cells) mosaicism for trisomy 7 and disomy X by interphase fluorescence in situ hybridization (FISH) analysis. Polymorphic DNA marker analysis excluded uniparental disomy (UPD) 7 and indicated a maternal origin of the chromosome aberration. The pregnancy was continued to 39 weeks of gestation, and a 3070-g healthy male baby was delivered. The cord blood had a karyotype of 46,XY, the umbilical cord had a karyotype of 48,XXY,+7[3]/46,XY[37], and the placenta had a karyotype of 48,XXY,+7. At age one month, the neonate was phenotypically normal, and interphase FISH analysis revealed 4.8% (5/105 cells) mosaicism on buccal mucosal cells and 8.9% (8/90 cells) mosaicism on urinary cells for trisomy 7 and disomy X, compared with 2% in normal control. Interphase FISH analysis on buccal mucosal cells at age two months revealed normal findings in 100/100 cells.ConclusionMosaic 48,XXY,+7 at amniocentesis without UPD 7 can be associated with a favorable fetal outcome. Cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes may occur in mosaic 48,XXY,+7 at amniocentesis.     

Prenatal diagnosis of mosaic ring chromosome 22 associated with cardiovascular abnormalities and intrauterine growth restriction

OBJECTIVES: To present the prenatal diagnosis and perinatal findings of mosaic ring chromosome 22. CASE: Amniocentesis was performed at 18 gestational weeks because of an advanced maternal age. Cytogenetic analysis of the cultured amniotic fluid cells revealed mosaicism for ring chromosome 22, 45,XX,-22[6]/46,XX,r(22)(p13q13.31)[15]. Abnormal fetal sonographic findings included small for gestational age, a ventricular septal defect, and truncus arteriosus. The pregnancy was terminated. Additional phenotypic findings included hypertelorism, epicanthal folds, and abnormal ears. Cytogenetic analysis of the cord blood lymphocytes revealed a complex mosaic karyotype, 45,XX,-22[7]/46,XX,r(22)(p13q13.31)[82]/46,XX,idic r(22)(p13q13.31;p13q13.31)[11]. Cytogenetic analysis of the hepatocytes also revealed mosaic r(22) with mosaicism for idic r(22) and monosomy 22. The deletion of distal 22q and the duplication of 22q11.2 on idic r(22), and the distal 22q deletion on r(22) were demonstrated by fluorescent in situ hybridization (FISH) analysis using 22q terminal probes at 22q13 and a DiGeorge syndrome critical region probe at 22q11.2. The breakpoint on distal 22q13 and the extent of the duplication of 22q on idic r(22) was determined by examining polymorphic markers specific for chromosome 22 using quantitative fluorescent polymerase chain reaction assays. The chromosomal aberration was of maternal origin. CONCLUSION: Molecular and FISH studies allow a better delineation of some prenatally detected aneuploidy syndromes and help elucidate the genetic pathogenesis. Fetuses having mosaic r(22) with a low level mosaicism for r(22) duplication/deletion may present cardiovascular abnormalities and intrauterine growth restriction on prenatal ultrasound.     

Prenatal diagnosis and molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from ring chromosome 2

ObjectiveTo present prenatal diagnosis and molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome (sSMC) derived from ring chromosome 2 [r(2)].Methods and ResultsA 35-year-old woman underwent amniocentesis at 17 weeks of gestation, because of advanced maternal age. Amniocentesis revealed a de novo ring-shaped sSMC in 11 of 23 colonies of cultured amniocytes. Repeated amniocenteses were made. The sSMC was characterized by array comparative genomic hybridization (aCGH), interphase fluorescence in situ hybridization (FISH) and quantitative fluorescent polymerase chain reaction (QF-PCR) on uncultured amniocytes. In uncultured amniocytes, aCGH showed a 39.49-Mb genomic gain in chromosome 2 encompassing 2q11.2→q21.2, interphase FISH revealed a mosaic level of 52% (52/100 cells), and QF-PCR manifested a diallelic pattern for chromosome 2, with gene dosage increase in the paternal allele of proximal 2q-specific DNA markers. In cultured amniocytes, the sSMC was characterized by metaphase FISH, spectral karyotyping (SKY) and multicolor banding (MCB) to contain the centromere and proximal 2q, and the karyotype was 47,XX,+r(2)(p11.1q21.2)[14]/46,XX[11]. The pregnancy was terminated. The fetus postnatally manifested facial dysmorphisms. Postnatal cytogenetic analyses revealed the karyotypes of 47,XX,+r(2)[12]/46,XX[28] in cord blood, 47,XX,+r(2)[7]/46,XX[33] in umbilical cord, 47,XX,+r(2)[13]/47,XX,+idic r(2)[3]/46,XX[24] in placenta and 47,XX,+r(2)[8]/47,XX,+idic r(2)[1]/46,XX[31] in amnion.ConclusionMolecular cytogenetic techniques such as aCGH, interphase FISH and QF-PCR on uncultured amniocytes, and SKY, MCB and metaphase FISH on cultured amniocytes are useful for characterization of the nature of a prenatally detected sSMC.     

Prenatal and postnatal characterization of Y chromosome structural anomalies by molecular cytogenetic analysis

We describe three cases in which we used fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR) and comparative genomic hybridization (CGH) to characterize Y chromosome structural anomalies, unidentifiable by conventional G-banding. Case 1 was a 46,X,+mar karyotype; FISH analysis revealed an entire marker chromosome highlighted after hybridization with the Y chromosome painting probe. The PCR study showed the presence of Y chromosome markers AMG and SY620 and the absence of SY143, SY254 and SY147. CGH results confirmed the loss of Yq11.2-qter. These results indicated the presence of a deletion: del(Y)(q11.2). Case 2 was a 45,X [14]/46,XY[86] karyotype with a very small Y chromosome. The PCR study showed the presence of Y chromosome markers SY620 and AMG, and the absence of SY143, SY254 and SY147. CGH results showed gain of Yq11.2-pter and loss of Yq11.2-q12. These results show the presence of a Yp isodicentric: idic(Y)(q11.2). Case 3 was a 45,X,inv(9)(p11q12)[30]/46,X,idic(Y)(p11.3?),inv(9)(p11q12)[70] karyotype. The FISH signal covered all the abnormal Y chromosome using a Y chromosome paint. The PCR study showed the presence of Y chromosome markers AMG, SY620, SY143, SY254 and SY147. CGH only showed gain of Yq11.2-qter. These results support the presence of an unbalanced (Y;Y) translocation. Our results show that the combined use of molecular and classical cytogenetic methods in clinical diagnosis may allow a better delineation of the chromosome regions implicated in specific clinical disorders.     

Cytogenetic discrepancy between uncultured amniocytes and cultured amniocytes in mosaic trisomy 15 at amniocentesis in a pregnancy with a favorable outcome

ObjectiveWe present prenatal diagnosis of mosaic trisomy 15 in a pregnancy with a favorable outcome.Case reportA 33-year-old, primigravid woman underwent amniocentesis at 19 weeks of gestation because non-invasive prenatal testing (NIPT) revealed gene dosage increase at chromosome 15. Cytogenetic analysis revealed a karyotype of 47,XX,+15[10]/46,XX[13]. Using uncultured amniocytes, array comparative genomic hybridization (aCGH) revealed arr [GRCh37] (X) × 2, (15) × 3 [0.75], multiplex ligation-dependent probe amplification (MLPA) analysis showed rsa [GRCh36] 15q11q13 (21,362,818–27,196,819) × 3 [0.76] and methylation-specific (MS)-MLPA analysis showed a methylation index = 0.41 with paternal gene dosage increase at 15q11-q13. Repeat amniocentesis at 25 weeks of gestation revealed a karyotype of 47,XX,+15[6]/46,XX[14]. Using uncultured amniocytes, quantitative fluorescent polymerase chain reaction (QF-PCR) assays excluded uniparental disomy (UPD) 15 and determined a paternal origin of the extra chromosome 15, aCGH analysis showed 75%–80% mosaicism for trisomy 15, and interphase fluorescence in situ hybridization (FISH) showed 45.5% (46/101 cells) mosaicism for trisomy 15. Repeat amniocentesis at 28 weeks of gestation revealed a karyotype of 47,XX,+15[2]/46,XX[23]. Using uncultured amniocytes, aCGH showed 75–80% mosaicism for trisomy 15, and FISH showed 70.6% (72/102 cells) mosaicism for trisomy 15. Using cultured amniocytes, QF-PCR assays excluded UPD 15. Cordocentesis at 30 weeks of gestation revealed a karyotype of 47,XX,+15[2]/46,XX[138]. Using cord blood, aCGH revealed 9% gene dosage increase at chromosome 15, and MS-MLPA analysis excluded UPD 15. At 36 weeks of gestation, a 2060-g phenotypically normal baby was delivered. The cord blood had 46, XX (40/40 cells). The placenta had 47,XX,+15 (40/40 cells). QF-PCR analysis on placenta showed a paternal origin of trisomy 15. FISH analysis on buccal mucosal cells at age 20 days showed 20% (20/100 cells) mosaicism for trisomy 15.ConclusionCytogenetic discrepancy may occur between uncultured and cultured amniocytes in mosaic trisomy 15 at amniocentesis. Cultured amniocytes may present progressive decrease in the levels of mosaicism for trisomy 15 as the fetus grows. Mosaic trisomy 15 at amniocentesis without UPD 15 can be associated with a favorable outcome.