Perinatal findings and molecular cytogenetic analysis of de novo partial trisomy 16q (16q22.1-->qter) and partial monosomy 20q (20q13.3-->qter)

OBJECTIVES: To present the perinatal findings and molecular cytogenetic analysis of de novo partial trisomy 16q and partial monosomy 20q and a review of the literature. CASE AND METHODS: Obstetric ultrasound at 33 weeks' gestation revealed intrauterine growth restriction (IUGR) and dolichocephaly in a 27-year-old primigravid woman. Prenatal cytogenetic diagnosis was not offered because of the late stage of gestation. A 2800-g male baby was delivered at 41 weeks' gestation by cesarean section because of fetal distress. The infant postnatally presented characteristic craniofacial dysmorphism, hypotonia, cleft palate, congenital heart defects, a subependymal cyst, and hypospadia. Cytogenetic analysis revealed an additional material attached to the terminal region of chromosome 20q. The parental karyotypes were normal. Spectral karyotyping (SKY), fluorescence in situ hybridization (FISH), and polymorphic DNA markers were used to investigate the origin of the de novo aberrant chromosome. RESULTS: SKY using 24-color probes, FISH using specific 16p, 16q, 20 centromeric, and 20q telomeric probes, and polymorphic DNA marker analysis confirmed maternal origin of the duplication of distal 16q and the deletion of terminal 20q. Karyotype of the proband was designated as 46,XY.ish der(20)t(16;20)(q22.1;q13.3)(SKY+,16qTEL+,20qTEL-). CONCLUSIONS: Partial trisomy 16q (16q22.1-->qter) and partial monosomy 20q (20q13.3-->qter) may be associated with the perinatal findings of IUGR, dolichocephaly, hypotonia, cleft palate, congenital heart defects, a subependymal cyst, and hypospadia. SKY, FISH, and genetic marker studies help in delineating the parental origin and the regions of the deletion and duplication in the de novo unbalanced translocation.     

Prenatal findings and molecular cytogenetic analyses of partial trisomy 12q (12q24.32-->qter) and partial monosomy 21q (21q22.2-->qter)

OBJECTIVES: To present the prenatal findings and molecular cytogenetic analyses of partial trisomy 12q and partial monosomy 21q, and a review of the literature. METHODS: Amniocentesis was performed at 23 gestational weeks in a 33-year-old woman because of abnormal sonographic findings. Amniocentesis revealed a derivative chromosome 21, or der(21), with a deletion on the region of 21q22.2 and an addendum of a small chromosomal segment of unknown origin. The maternal karyotype was subsequently found to be 46,XX,t(12;21)(q24.32;q22.2). Level II ultrasound showed microcephaly, micrognathia, a ventricular septal defect, and rocker-bottom feet. The pregnancy was terminated. A malformed infant was delivered without the phenotype of holoprosencephaly (HPE). Fluorescence in situ hybridization (FISH) and polymorphic DNA markers were used to investigate the involved chromosomal segments. RESULTS: FISH study showed the absence of the signal of 21q subtelomeric probe and the presence of the signal of 12q subtelomeric probe in the der(21).The fetal karyotype was 46,XY,der(21) t(12;21)(q24.32;q22.2)mat. Genetic marker analysis showed a deletion at 21q22.2 and a breakpoint between D21S156 (present) and D21S1245 (absent). The deleted segment was measured about 4.5 Mb encompassing the HPE critical region. CONCLUSIONS: Molecular genetic analyses help in determining the prenatally detected unbalanced cryptic translocation as well as parental balanced subtle translocation. A duplication of 12q24.32-->qter and a deletion of 21q22.2-->qter may be associated with prenatal sonographic findings of microcephaly, borderline ventriculomegaly and cerebellar hypoplasia, micrognathia, a ventricular septal defect, and rocker-bottom feet. Haploinsufficiency of the HPE critical region at 21q22.3 may not cause an HPE phenotype.     

Prenatal diagnosis of partial monosomy 18p(18p11.2-->pter) and trisomy 21q(21q22.3-->qter) with alobar holoprosencephaly and premaxillary agenesis

A prenatal diagnosis of partial monosomy 18p(18p11.2-->pter) and trisomy 21q(21q22.3-->qter) in a fetus with alobar holoprosencephaly (HPE) and premaxillary agenesis (PMA) but without the classical Down syndrome phenotype is reported. A 27-year-old primigravida woman was referred for genetic counselling at 21 weeks' gestation due to sonographic findings of craniofacial abnormalities. Level II ultrasonograms manifested alobar HPE and median orofacial cleft. Cytogenetic analysis and fluorescence in situ hybridization (FISH) on cells obtained from amniocentesis revealed partial monosomy 18p and a cryptic duplication of 21q,46,XY,der(18)t(18;21)(p11.2;q22.3), resulting from a maternal t(18;21) reciprocal translocation. The breakpoints were ascertained by molecular genetic analysis. The pregnancy was terminated. Autopsy showed alobar HPE with PMA, pituitary dysplasia, clinodactyly and classical 18p deletion phenotype but without the presence of major typical phenotypic features of Down syndrome. The phenotype of this antenatally diagnosed case is compared with those observed in six previously reported cases with monosomy 18p due to 18;21 translocation. The present study is the first report of concomitant deletion of HPE critical region of chromosome 18p11.3 and cryptic duplication of a small segment of distal chromosome 21q22.3 outside Down syndrome critical region. The present study shows that cytogenetic analyses are important in detecting chromosomal aberrations in pregnancies with prenatally detected craniofacial abnormalities, and adjunctive molecular investigations are useful in elucidating the genetic pathogenesis of dysmorphism.     

Sacrococcygeal teratoma in a fetus with prenatally diagnosed partial trisomy 10q (10q24.3-->qter) and partial monosomy 17p (p13.3-->pter)

OBJECTIVE: Clinical features of the distal 10q trisomy syndrome consist of mental retardation, facial dysmorphism and renal and cardiac anomalies. The presence of a sacrococcygeal teratoma (SCT) in a fetus with distal 10q trisomy has not been reported yet. METHODS: A 33-year-old, G5, P2 woman with a singleton pregnancy was referred to our clinic at 24 weeks of gestation for further evaluation of a fetal sacral exophytic mass. Detailed fetal sonographic examination together with chromosomal analysis by amniocentesis was performed. RESULTS: The scan revealed a large SCT together with a persistent right umbilical vein, cardiomegaly, bilateral mild hydronephrosis and intrauterine growth retardation. The fetal karyotype showed distal 10q trisomy (10q24.3-->qter) distal monosomy 17 (p13-->pter). The fetus died after a preterm delivery at 28 weeks of gestation. Postnatal examination confirmed the prenatal findings and added the typical facial features of this syndrome, which consisted of prominent forehead, small nose with depressed nasal bridge, micrognathia and bow-shaped mouth. CONCLUSION: This case provides further evidence of a possible association between chromosomal aberrations in SCTs.     

Partial monosomy 13q (13q21.32--->qter) and partial trisomy 8p (8p1--->pter) presenting with anencephaly and increased nuchal translucency: array comparative genomic hybridization characterization

ObjectiveTo present array comparative genomic hybridization (aCGH) characterization of partial monosomy 13q (13q21.32→qter) and partial trisomy 8p (8p12→pter) presenting with anencephaly and increased nuchal translucency (NT).Case ReportA 34-year-old primigravid woman was referred to the hospital at 12 weeks of gestation for termination of the pregnancy because of major structural abnormalities of the fetus. Prenatal ultrasound revealed a malformed fetus with anencephaly and an increased NT thickness of 5 mm at 12 weeks of gestation. Cytogenetic analysis of the fetus revealed a derivative chromosome 13. The mother was subsequently found to carry a balanced reciprocal translocation between 8p12 and 13q21. Bacterial artificial chromosome-based aCGH using fetal DNA demonstrated partial trisomy 8p and partial monosomy 13q [arr cgh 8p23.3p12 (RP11-1150M5→RP11-1145H12)×3, 13q21.32q34 (RP11-326B4→RP11-450H16)×1]. Oligonucleotide-based aCGH showed a 36.7-Mb duplication of distal 8p and a 48.4-Mb deletion of distal 13q. The fetal karyotype was 46,XY,der(13) t(8;13)(p12;q21.32)mat. The maternal karyotype was 46,XX,t(8;13)(p12;q21.32).ConclusionThe 13q deletion syndrome can be associated with neural tube defects and increased NT in the first trimester. Prenatal sonographic detection of neural tube defects should alert chromosomal abnormalities and prompt cytogenetic investigation, which may lead to the identification of an unexpected parental translocation involving chromosomal segments associated with neural tube development.     

Molecular cytogenetic characterization of a de novo unbalanced translocation leading to trisomy 17q25-->qter and monosomy 18p11.3-->pter in a girl with dysmorphic features

An 18-year-old, gravida 1 underwent percutaneous umbilical blood sampling (PUBS) because of positive triple screen, oligohydramnios and markedly short fetal bones. Chromosome analysis showed an abnormal chromosome 18 with unidentified chromatin at the end of the p-arm. Parental karyotypes were normal. FISH analyses with wcp18 showed additional material of unknown origin on the derivative chromosome 18. Further FISH analysis with subtelomeric probes showed normal signals for the long arm of chromosome 18 (18q23) while no signals were observed for the short arm (18p11.32). These findings were confirmed using a YAC probe from the short arm of 18. The infant was delivered at 30 weeks of gestation. At age 3 months, she was developmentally delayed and has multiple dysmorphic features. Further molecular cytogenetic studies including M-FISH and subtelomere probes showed that the additional material on chromosome 18 consisted of the distal 17q25-->qter region. Based on these studies the karyotype has been interpreted as 46,XX,der(18)t(17;18)(q25;p11.32). To the best of our knowledge, this is the first report of partial monosomy 18p and partial trisomy 17q in a patient with no major CNS malformations. This case shows the importance of molecular cytogenetic techniques in detailed characterization of de novo chromosome rearrangements.     

Prenatal diagnosis of monosomy 4p14-->pter and trisomy 11q25-->qter: clinical presentations and outcomes

We present the case of a pregnant woman with low free beta-HCG in maternal serum Down syndrome screening that led to prenatal diagnosis of a fetus with 46,XY,der(4)t(4;11)(p14; q25). This chromosomal aneuploidy resulted from unbalanced segregation of a paternal balanced translocation, t(4;11)(p14;q25). Prenatal ultrasound revealed intrauterine growth restriction, cleft lip and palate, a thick nuchal fold, a single umbilical artery, and pyelectasis. Array-based comparative genomic hybridization and short tandem repeat markers further located the exact breakpoint of translocation. The woman had her pregnancy terminated at 23 weeks of gestational age. The proband had general appearance of Wolf-Hirschhorn syndrome and some unique findings, including single umbilical artery, severe immunoglobulin deficiency, scalp defect, and underlying bony defect. Our case underscores the importance of fetal karyotyping when low maternal serum free beta-HCG is found. It also adds information on the fetal presentations of monosomy 4p14-->pter and trisomy 11q25-->qter.     

Prenatal diagnosis of partial trisomy 3p (3p21-->pter) and partial monosomy 11q (11q23-->qter) associated with abnormal sonographic findings of holoprosencephaly, orofacial clefts, pyelectasis and a unilateral duplex renal system

Patients with partial trisomy 3p seldom present major dysmorphic features, and holoprosencephaly occurs in only 10% of the cases with partial trisomy 3p. It has been suggested that multiple genetic hits or environmental exposures are required for the clinical expression of holoprosencephaly. At 16 weeks of gestation, prenatal sonography identified a fetus with holoprosencephaly, orofacial clefts, pyelectasis, and a unilateral duplex renal system. Amniocentesis revealed the karyotype of 46,XX,der(11)t(3;11)(p21;q23)pat with partial trisomy 3p (3p21-->pter) and partial monosomy 11q (11q23-->qter). The pregnancy was subsequently terminated. Postnatally, the proband showed hypotelorism, a depressed nasal bridge, orofacial clefts and holoprosencephaly-premaxillary agenesis. The present case provides evidence that partial trisomy 3p/monosomy 11q can be a genetic cause of holoprosencephaly and del(11)(q23-->qter) is associated with a duplex renal system.     

Duplication dup(1)(q32q44) detected by comparative genomic hybridization (CGH): further delineation of trisomies 1q

Partial trisomy 1q is rare and mostly the result of an abnormal segregation of parental translocation chromosomes and their homologues. Only 31 cases have been described with pure partial trisomy 1q. In the fetus presented, chromosome analysis after amniocentesis had shown an unbalanced male karyotype with an aberrant chromosome 1. A de novo terminal duplication of the long arm was suspected but could not be verified by FISH in 1994. Five years after fetal death, retrospective identification of the additional material in 1q could finally be achieved by comparative genomic hybridization (CGH) using DNA extracted from formalin-fixed and paraffin-embedded fetal tissues. A direct duplication dir dup (1)(pter-->q44::q32.1-->qter) was found. Only 6 other individuals with duplication of this segment have been described so far. Comparative delineation of a dup1q phenotype with regard to size and origin of the dup (1q) segment evidenced that large duplications as well as proximal and interstitial duplications coincide with more severe visceral malformations, severe mental retar- dation and a short life span. Terminal duplications (1q32-->qter) concur with less severe malformations and longer periods of survival, but marked mental retardation. With small terminal duplications (1q42-->qter) dysmorphisms are usually mild and intellectual performance is mostly in the normal range.     

Two unbalanced segregation products due to a maternal t(7;16)inv(16)

We report a prenatal case of a maternally inherited abnormal chromosome 16, originally interpreted as a pericentric inversion only, but after family studies re-interpreted as a pericentric inversion (16) accompanied by an unbalanced (7;16) translocation. Because of the inversion 16 and an elder son with developmental delay and craniofacial dysmorphic features, in the past karyotyped as 46,XY, the chromosomes 16 of the mother and son were carefully re-examined. Using a whole chromosome 16 paint and sub-telomere probes of 16p and 16q, the karyotype of the mother was shown to be 46,XX,inv(16)(p11.2q23.2).ish t(7;16)(q36;p13.3)inv(16). Subsequently one chromosome 16 of the elder son appeared to be a der(16)t(7;16)(q36;p13.3). This is probably the result of a meiotic crossover between the chromosomes 16 in the mother. The prenatal karyotype was finally interpreted as 46,XY,inv(16)(p11.2q23.2).ish der(16)t(7;16)(q36;p13.3)inv(16). This is the same cytogenetic imbalance as his elder brother: a partial trisomy of chromosome 7 (q36-->qter) and a partial monosomy of chromosome 16 (p13.3-->pter).     

Pre- and perinatal findings in partial trisomy 7q resulting from balanced parental translocations t(7;21) and t(4;7)

We report on a fetus and a newborn, both with partial trisomy 7q21-->qter due to different familial translocations, t(7;21)(q21.2;p12) and t(4;7)(q35;q21.2). Postmortem examination of the 19-week-old female fetus disclosed dysmorphic features, cleft palate, anomalies of the great vessels, intestinal malrotation and uterus bicornis. The newborn girl revealed a pattern of minor anomalies, cleft palate, cerebellar hypoplasia, and anomalies of pancreas, gall bladder and appendix. The clinical findings in three other reported fetuses with partial trisomy 7q described so far are reviewed. A duplication 7q21-->qter, as found in the propositi, has only been described in 11 patients who all had a concurrent partial monosomy. Patient 1 is particularly interesting since she is, to our knowledge, the first reported case with pure trisomy 7q21/22-->qter. We reviewed the phenotype of the previously described patients, compared it with the propositae, and summarized the clinical features of pure trisomy 7q21/22-->qter.     

Prenatal diagnosis of jumping translocation involving chromosome 22 with ultrasonographic findings

We report on the prenatal diagnosis and ultrasonographic findings of a second-trimester fetus with jumping translocation involving chromosome 22. A 28-year-old gravida 2, partus 1, Turkish woman was referred for genetic counselling and ultrasonographic examination at 18 weeks' gestation because of a high risk of trisomy 21 in triple test. Prenatal ultrasonography showed tetralogy of Fallot with a diverticular dilatation of the pulmonary artery, flattened brow, complete absence of the right upper limb, hypospadias, oligodactyly (three digits) in left hand and in both feet, and hyperechogenic abdominal foci. Amniocentesis revealed a karyotype of 46,XY[4]/46,XY,-8,+ der(8),t(8;22)(q24.3;q11.21)[2]/45, XY,-22,-8,+ der(8)t(8;22)(q24.3;q11.21)[22]/45,XY,-22,-5,+ der(5)t(5;22)(q35.3;q11.21)[44]. A C-banding and FISH study with a specific centromeric probe (D14Z1/D22Z1) for chromosome 22 was made. In our case, partial monosomy for the regions 22q11.21-->22pter, 8q24.3-->8qter and 5q35.3-->5qter may partially explain the fetal malformations.     

Prenatal diagnosis and molecular cytogenetic characterization of a derivative chromosome der(18;18)(q10;q10)del(18)(q11.1q12.1)del(18)(q22.1q22.3) presenting as apparent isochromosome 18q in a fetus with holoprosencephaly

ObjectiveTo present prenatal diagnosis and molecular cytogenetic characterization of a derivative chromosome der(18;18)(q10;q10)del(18)(q11.1q12.1)del(18)(q22.1q22.3).Materials, Methods, and ResultsA 32-year-old woman was referred for genetic counseling of prenatally detected isochromosome 18q [i(18q)]. She had undergone amniocentesis at 19 gestational weeks because of a trisomy 18 risk of 1/39 derived from abnormally low levels of maternal serum unconjugated estriol, inhibin A, α-fetoprotein, and total β-human chorionic gonadotropin. Amniocentesis revealed a karyotype of 46,XX,i(18)(q10). Parental karyotypes were normal. Prenatal ultrasound showed alobar holoprosencephaly. Repeated amniocentesis was requested and performed at 21 gestational weeks. Array-comparative genomic hybridization analyses revealed a 14-Mb deletion of 18p11.32-p11.21, a 37.8-Mb duplication of 18q12.1-q22.1, and a 6.9-Mb duplication of 18q22.3-q23. Metaphase fluorescence in situ hybridization study showed the absence of an 18q12.1-specific probe signal in one arm and the absence of an 18q22.2-specific probe signal in the other arm of the derivative chromosome. Quantitative fluorescent polymerase chain reaction analysis determined a paternal origin of the derivative chromosome. The cytogenetic result was 46,XX,der(18;18)(q10;q10)del(18)(q11.1q12.1)del(18)(q22.1q22.3). The fetus postnatally manifested cebocephaly.ConclusionConcomitant monosomy 18p and trisomy 18q can be associated with holoprosencephaly and abnormal maternal serum screening results. Array-comparative genomic hybridization, fluorescence in situ hybridization, and quantitative fluorescent polymerase chain reaction are useful in genetic counseling of prenatally detected isochromosomes by providing information on the origin and genetic components of the isochromosome.     

Placental mosaicism in a case of 46,XY,-22,+t(22;22)(p11;q11) or i(22q) diagnosed at amniocentesis.

46,XY,-22,+t(22;22)(p11;q11) or i(22q) was diagnosed in 15/15 cells from two cultures from the amniotic fluid culture of a 31-year-old patient whose fetus demonstrated cystic hygroma on ultrasound. Cytogenetic studies performed on fetal skin from the abortus revealed the same karyotype as that seen on amniocentesis, but the placenta demonstrated a 46,XY/46,XY,-22,+t(22;22) or i(22q) mosaicism, with 65 per cent of the cells being 46,XY. This case provides an example of placental mosaicism for a normal male karyotype, while the fetus demonstrated non-mosaic trisomy 22.     

Distal partial trisomy 1q: report of two cases and a review of the literature

We report on two cases with partial trisomy 1q syndrome. One case was a mid-trimester fetus with multiple malformations that was prenatally diagnosed with a de novo distal partial trisomy 1q. Prenatal ultrasound at 24th gestational week demonstrated the presence of cleft lip and palate, increased biparietal diameter and decreased abdominal circumference. Cytogenetic analysis (GTG banding) and subsequent fluorescence in situ hybridization (FISH) using whole chromosome paint 1 and multicolor banding (MCB) demonstrated an aberrant karyotype 46,XY,dup(1)(q31q43 approximately 44). The second case was a newborn male infant with multiple congenital malformations. He had a derivative chromosome 18 as a result of a maternal insertion involving chromosomes 1 and 18. Further analyses including MCB showed his karyotype as 46,XY,ins(18;1)(q22;q23q31.1 approximately 32). The present cases and a review of the literature suggest that partial trisomy of the long arm of chromosome 1 is a distinct clinical entity.     

Segregation of digital number with partial monosomy or trisomy of 13q in familial 5;13 translocation.

It has been postulated that the deletion of band 13q22 may be associated with digital malformations, especially thumb and big toe anomalies. We report a family where the mother is carrying a balanced translocation between chromosomes 5p15 and 13q22. The offspring have a specific and well-defined phenotype depending on which is the unbalanced chromosome in the karyotype. When a partial trisomy of 13q22-->qter is present, the fetuses have polydactyly in the four limbs, and when the fetus is carrying a partial monosomy of this portion, an oligodactyly in all members can be observed.     

Prenatal diagnosis of partial trisomy 4q26-qter and monosomy for the Wolf-Hirschhorn critical region in a fetus with split hand malformation

We describe the results of prenatal analyses and postnatal findings in a male fetus with a partial trisomy for the long arm and a small terminal monosomy for the short arm of chromosome 4 with the following karyotype: 46,XY,add(4)(p16.3).ish dup(4)(q26qter)(wcp4+, D4S2336x3,AFMb280xa5x2,4ptel-,WHCR-). G-banding did not identify the origin of the additional chromosomal segment, but this was achieved prenatally by application of RxFISH and whole chromosome painting probes. Subsequent FISH analysis with region-specific YAC clones was used to relate the phenotypic findings such as bilateral split hand formation, specific cardiac and kidney anomalies, microtia, and hypoplastic thorax more exactly to the partial trisomy of the segment 4q26-qter.     

Prenatal diagnosis of partial trisomy 3p(3p23-->pter) and monosomy 7q(7q36-->qter) in a fetus with microcephaly alobar holoprosencephaly and cyclopia.

We report the prenatal diagnosis of partial trisomy 3p(3p23-->pter) and monosomy 7q(7q36-->qter) in a fetus with microcephaly, alobar holoprosencephaly and cyclopia. A 26-year-old primigravida woman was referred for genetic counselling at 23 gestational weeks due to sonographic findings of intra-uterine growth retardation and cranio-facial abnormalities. Level II ultrasonograms further demonstrated alobar holoprosencephaly, a proboscis above the eye and a single median orbit consistent with cyclopia. Genetic analysis and fluorescence in situ hybridization on cells obtained from amniocentesis showed distal 3p trisomy (3p23-->pter) and 7q36 deletion, 46,XX,der(7)t(3;7)(p23;q36), resulting from a paternal t(3;7) reciprocal translocation. The pregnancy was terminated. Autopsy further confirmed the presence of arrhinencephaly, agenesis of the corpus callosum and a single ventricle of the brain. The phenotype of this antenatally diagnosed case is compared with those observed in 10 previously reported cases with simultaneous occurrence of partial trisomy 3p and terminal deletion 7q. All cases are associated with severe forms of holoprosencephaly and facial dysmorphism. This delineates an autosomal imbalance syndrome or a dosage effect involving duplication of distal 3p/deficiency of terminal 7q and dysmorphogenesis of the forebrain and mid-face.     

Partial duplication of 3q and distal deletion of 10q inherited from a maternal balanced translocation.

Partial trisomy 3q syndrome is often the result of an unbalanced translocation or inversion. The duplicated segments are mostly from 3q25 to 3qter. We describe a karyotype of 46,XY,der(10)t(3;10)(q25.3;q26.1) in a 1-day-old male infant who presented with multiple congenital anomalies including synophrys, a long philtrum, thin lips with down-turned angles of the mouth, micrognathia, a high-arched and cleft palate, clenched hands, genital hypoplasia, cryptorchidism, a large ventricular septal defect, a subependymal cyst, and corpus callosum hypoplasia. The patient had cardiopulmonary distress resulting from multiple congenital anomalies. He died of heart failure at the age of 18 days. The chromosome aberration resulted from a maternal balanced translocation. The dup(3q) syndrome superficially resembles but can be distinguished from Brachmann-de Lange syndrome. Craniofacial features, cleft palate and urinary tract anomaly are more frequent in dup(3q) syndrome. Oligodactyly and phocomelia are more characteristic of Brachmann-de Lange syndrome.     

Prenatal diagnosis of microdeletion 16p13.11 combination with partial monosomy of 2q37.1-qter and partial trisomy of 7p15.3-pter in a fetus with bilateral ventriculomegaly, agenesis of corpus callosum, and polydactyly

ObjectiveTo present a prenatal diagnosis of microdeletion 16p13.11 with partial monosomy of 2q37.1-qter and partial trisomy of 7p15.3-pter in a fetus with bilateral ventriculomegaly, agenesis of corpus callosum, and polydactyly.Case ReportA 41-year-old well-being Taiwanese, nulligravida woman received amniocentesis at a gestational age of 18 weeks for advanced maternal age. The fetus' karyotype showed 46,XY,der(2)t(2;7)(q36.2;p15.1). Both parents also received cytogenetic examinations and the mother's karyotype revealed 46,XX,t(2;7)(2q36.2;p15.1). High-resolution ultrasound showed the fetus had bilateral ventriculomegaly, agenesis of corpus callosum, and polydactyly of the right hand. After the termination of this pregnancy, the whole genome oligonucleotide-base array comparative genomic hybridization (CGH) by using fetal skin cells demonstrated a 8.44-Mb deletion at 2q37.1 (234602276-243041305), a 22.8-Mb duplication (65558-22869338) at 7p15.3, and an additional 1.32-Mb deletion (14968855-16292235) at 16p13.11.ConclusionArray CGH is a useful tool not only to discover the genomic imbalance at the breakpoints as well as to detect unexpectedly complex rearrangements in other chromosomes. Our case also provided evidence that genomic aberration at chromosome 16p13.11 involves in the formation of polydactyly.