Rapid identification of multiple supernumerary ring chromosomes with a new FISH technique.

Multiple supernumerary ring chromosomes are a rare cytogenetic finding which is poorly understood. With the introduction of FISH techniques, their chromosomal origin can now be defined clearly. The techniques described previously are complicated and time consuming. We report a new rapid technique which has been used to investigate two new cases. Multiple probes were hybridised to a single slide by means of marking the underside with a diamond pen to form a grid of squares, pipetting fixed cell suspension into the centre of each square, forming a rubber solution grid on the denatured, dehydrated slide following the lines on the underside, adding a mixture of probes into each square, and sealing the slide with a silicone rubber rim and a covering slide. The type of probe and the size, dimensions, and number of squares in the grid can be tailored to individual cases. The two new cases examined here are mosaic for three (case 1) and four (case 2) supernumerary ring chromosomes derived from different chromosomes. Normal cell lines were also present. The karyotypes were established as 47,XY,+r(4)/47,XY,+r(17)/.../48,XY,+r(17),+r(20)/ 49,XY,+r(4),+r(17),+r(20)/46,XY for case 1 and 47,XX,+r(4)/47,XX,+r(8)/47,XX,+r (10)/48,XX,+r(X),+r(4)/... /49,XX,+r(X),+r (8),+r(10)/46,XX for case 2. Our findings suggest that the ring chromosomes were formed during meiosis, perhaps involving complex rearrangements, resulting in a germ cell containing all markers, with subsequent loss of markers during cell division. Our second case also shows that the outcome is not invariably mental or physical handicap.     

Chromosome studies in induced abortions

Chromosome studies of 172 cases of induced abortions during 1967-1972 in Denmark using 212 cultures from fetal skin, placenta, and amniotic fluid cells showed 6 (3.48%) fetuses with aberations. The aberrations were: two 47, XY+C; one 47, XY+E; one 47, XY+G; one 46, XX/47, XX,+C; and one 46, XX/47, XX,+G. Besides these aberrations, tetraploidy was observed in cultures from amniotic fluid and membranes in frequencies up to 10%. Only 1 case of aberration was found in maternal age groups of less than 34 years (.7%) as opposed to 3 cases (27%) in 40+ groups. Average maternal age for total material was 26.5 years and for aberrations 33.6 years. Average gestational age was 12 1/2 weeks, with 10 1/2 weeks for aberrations. Sex ratio of males to females was .88 for abortions of the first trimester and 1.30 for second trimester.     

Abnormal chromosome 9 in a neonate program. Report of three cases

We describe three cases with abnormal chromosome 9. Patient 1 shows translocation in a homologous chromosome, with a karyotype of 46,XX,t(9;9)(9pter----cen----9pter; 9qter----cen::9q13----9qter), 1qh+. This case has a variety of anomalies, including brain anomalies. Patient 2 shows a partial trisomy 9p with a karyotype of 47,XY,+del(9)(pter----q11:). The patient has the typical clinical features of 9p trisomy syndrome. Patient 3 is unique because of partial 9p tetrasomy mosaicism without phenotypic abnormalities; the karyotype is mos 46,XY/47,XY,+dic(9)(pter----cen----q21::q21----cen----pter).     

Phylloid pattern of pigmentary disturbance in a case of complex mosaicism

Among the various types of pigmentary disturbances associated with mosaicism, the phylloid pattern (Greek phyllon = leaf, eidos = form) is characterized by multiple leaf-like patches reminiscent of an art nouveau painting. The number of cases displaying this unusual pattern is so far limited. We describe a phylloid pattern of hypomelanosis in a 3-year-old girl with multiple congenital anomalies including microcephaly, midfacial hypoplasia, cleft lip, coloboma, posteriorly rotated ears, pectus carinatum, and pronounced mental and physical retardation. In addition, this child had oval or oblong patches of hyperpigmentation involving the trunk in a horizontal arrangement dissimilar from the phylloid hypomelanotic pattern. In peripheral blood lymphocytes a karyotype 46,XX,-13,+t(13q;13q) was consistently found, whereas cultured skin fibroblasts showed a complex form of mosaicism comprising three different abnormal cell lines (46,XX,-13,+t(13q;13q)/45,XX,-13/45,XX,-13,+frag). This case provides further evidence that the phylloid pattern represents a separate category of pigmentary disturbance to be distinguished from other types of cutaneous mosaicism such as the lines of Blaschko or the checkerboard arrangement.     

Results and Pitfalls in Prenatal Cytogenetic Diagnosis

Since 1969, we have cultured over 200 diagnostic amniotic fluids. Of these, 183 were for cytogenetic diagnosis. The chromosome analysis was successful in 168 cases. The indications and the results of the affected fetuses (followed by therapeutic abortion) are: (1) previous child with Down's syndrome: 62 cases (1:47,XX,+21); (2) advanced maternal age: 54 cases (1:47,XXY; 1:45,X/46,XY mosaicism; 1:47,+18); (3) previous child with multiple anomalies: 12 cases; (4) previous child with 47,XY,+18 or 47,+13: five cases; (5) translocation carrier: two cases; (6) parental mosaicism: three cases; (7) X-linked disorders: six cases (3:XY); (8) others: 24 cases. We have found firstly, that for prenatal sex determination, karyotype analysis of the cultured amniotic fluid cells is the only accurate means and that caution must be taken if sex chromatin and Y-fluorescent body determination from the uncultured amniotic fluid cells is used. Secondly, that diagnosis of chromosomal mosaicism can be problematic as exemplified by our case of 45,X/46,XY mosaicism, where only 45,X cells were recovered from the first culture. Thirdly, that in cases with enlarged satellites, cells of late prophase or early metaphase must be used to eliminate confusion with translocations. We encountered three cases of enlarged satellites—one in the D group and two in the G group—and all three resulted in normal infants. Fourthly, that the karyotype may be altered by contamination and/or treatment or other unknown factors. We have observed two such cases where each mother delivered a normal infant.     

Ullrich-Turner phenotype with unusual manifestation in a patient with mosaicism 45,X/47,XX,+18

We report on a girl with Ullrich-Turner phenotype and 45,X/47,XX,+18 chromosomal mosaicism. Only two other patients with similar mosaicism have been reported, both girls with XY sex chromosome constitution. The face of the patient was highly asymmetric, the right side being almost normal, the left showing a typical Ullrich-Turner syndrome appearance. This clinical impression was strengthened by photographic doubling of both hemifaces. The patient had normal intelligence and did not show any stigmata of trisomy 18. © 1996 Wiley-Liss, Inc.     

Cytogenetic abnormalities in hepatoblastoma: report of two new cases and review of the literature suggesting imbalance of chromosomal regions on chromosomes 1, 4, and 12

Two cases of hepatoblastoma with unique karyotypic changes are described. One case was that of a 2-year-old boy with an unbalanced chromosomal translocation involving 4q35 as the sole chromosomal abnormality. The clonal karyotype of this tumor was 46,XY,add(4)(q35)[3]/46,XY[9]. In the other case, that of a 2-year-old boy, karyotypic analyses revealed the clonal karyotype as 57,XY,+del(1)(p22),+2,+5,+6,+7,+8,+del(12)(p12),+18,+19,+20,+22[4]/46,XY[12]. Review of these two cases, together with previous reports, underscored the significance of numerical and/or structural chromosomal abnormalities of 1q, 4q, 2, 8, and 20 in the development of hepatoblastoma. The present results show that imbalance of the terminal region of 4q could be the sole chromosomal abnormality in a hepatoblastoma. We also found that imbalance of chromosomal regions on chromosomes 1 and 12 may contribute to the development of hepatoblastoma.     

Effect of sex chromosome aneuploidy on growth of human skin fibroblasts in cell culture

Growth of human skin fibroblast lines with sex chromosome aneuploidy was studied in cell culture. Two lines were derived from individuals with 45,X and two from individuals with 47,XYY chromosome constitution. The aneuploid cell lines were compared with normal skin fibroblasts derived from age-matched same-sex siblings. To ensure similar conditions in culture, each study-control pair was treated simultaneously and equally in all steps. Growth in both 45,X cell cultures slowed down earlier than in control cultures. One of the 47,XYY cultures grew faster and the other at a similar speed to the control culture. Thus, the 45,X cell lines seemed to have lesser, and one of the 47,XYY cell lines greater, growth potential than the 46,XX and 46,XY cells, respectively. These differences in the final cell numbers may relate to changes in the rate of cell division of the aneuploid cell lines. However, the results do not support the hypothesis that an increasing number of sex chromosomes decreases the rate of cell division.     

Cytogenetic studies in four cases of Acute Promyelocytic Leukemia (APL)

Four patients diagnosed as having acute promyelocytic leukemia (APL) were cytogenetically examined. They had an identical abnormality, 46,XX or XY,t(15q+;17q−), while one of them had two additional cell lines, 47,XY,+8,t(15q+;17q−) and 46,XY,15q+,i(17q−). The break points were tentatively assigned at bands 15q23 and 17q12.     

Origin and mechanism of formation of 45,X/47,XX,+21 mosaicism in a fetus

Chromosome analysis of amniotic fluid cells from a 17-week-old fetus with a nuchal cystic hygroma showed a 45,X/47,XX,+21 karyotype. Analyses of cord blood lymphocytes, skin fibroblasts, amniotic membrane, and chorionic villi demonstrated both cell lines in various proportions. We studied the origin and mechanism of formation of the double mosaic aneuploid using Q-banded chromosomal heteromorphisms, and one RFLP, two VNTRs, one tetranucleotide repeat, 28 CA repeat markers, mapped to every member of chromosomes. The heteromorphic markers examined showed no discordant patterns in parent-to-child transmission or between the two cell lines except for those in chromosomes 21 and X. Fetal DNA was extracted from its established monoclonal fibroblast cell lines with 45,X or 47,XX,+21 karyotypes. Genotyping with the DNA markers showed that each cell line was identical at every locus, except for chromosome 21 or X loci, indicating that the fetus was not a chimera but a mosaic. The 21-trisomic cells had one paternal allele and two maternal heterozygous alleles at the D21S270 locus, and the 45,X (21-disomic) cells had two biparental alleles. Alleles at two X chromosomal loci, DXS991 and DXS8057, were biparental in the 47,XX,+21 cells, whereas only the paternal allele was retained in the 45,X cells. Based on these findings, we concluded that the fetus started as a 47,XX,+21 zygote that had resulted from nondisjunction at the maternal first meiotic division and that one each of the maternally derived chromosomes 21 and X was lost during an early mitotic division, leading to the mosaicism. Am. J. Med. Genet. 75:432-437, 1998. © 1998 Wiley-Liss, Inc.     

Cytogenetic studies of eight primary gastric cancers.

Cytogenetic analysis was performed on eight primary gastric cancers. Three of them had simple chromosome changes: 47,XX,+X/48,XX,+X,+X; 48,XX,+8,+19,t(3;5) (q21;q31) and 47,XY,+del(7)(q22). The five others had complicated chromosome changes; both 3p- and 7q- were noted in four cases and i(5p) was noted in two cases.     

Confined placental chimerism: Prenatal and postnatal cytogenetic and molecular analysis,and pregnancy outcome

The presence of two cell lines in chorionic villi sampling (CVS) represents a significant complication in CVS analysis, interpretation, and counseling. We report on the cytogenetic and molecular analysis of a pregnancy that was conceived on clomiphen citrate. Two cell lines (46,XX and 47,XY, + 9) were discovered in CVS analysis done for maternal age; 94% of the cells in the culture were 46,XX and 6% were 47,XY, + 9 (the direct preparation was 46,XX). As neither line could have derived from the other, chimerism and not mosaicism was suspected, with the 47,XY, + 9 cells deriving from a co-twin whose demise was the result of the autosomal trisomy. At a subsequent amniocentesis, only normal female cells were observed and a normal female infant was delivered at term. Cytogenetic analysis done on the infant's peripheral blood and on a sample of an umbilical vessel showed only 46,XX cells, while amnion and a fibrotic area of the placenta contained 2 cell lines, 46,XX and 47,XY, + 9. Molecular analysis of 3 different tissues was done by the polymerase chain reaction (PCR) and Southern blotting, using Y specific primers and probes, respectively. The presence of Y specific DNA was detected in the placenta and amnion, but not in the umbilical blood vessel. These data excluded true chimerism in the fetal tissues at the level of about 1 in 10⁵ cells and have defined for the first time probable confined placental chimerism (CPC), the result most likely of a “vanishing twin.” Whenever two cell lines are found in CVS, especially in the setting of pharmacologically stimulated ovulation, the possibility of CPC should be considered. The effects of CPC on placental function and fetal outcome merit further study. © 1994 Wiley-Liss, Inc.     

Triple mosaicism 45,XY,--18/46, XY/47,XY,+18.

A patient with symptoms clinically resembling Edwards's syndrome is presented. Cranial asymmetry, thoracic and lumbar hemivertebrae, and an additional rib were the unusual features. The cytogenetic studies revealed the coexistence of three separate cell lines with 45,XY,--18/46,XY/47,XY,+18 complement.     

Pigmentary mosaicism of the hyperpigmented type in two half-brothers

Pigmentary mosaicism is a heterogeneous cutaneous phenotype that is often associated with extracutaneous anomalies. It is widely accepted that these phenotypes arise de novo as a result of a postzygotic mutation, leading to a mosaic status of the embryo. In the vast majority of cases, the occurrence of pigmentary mosaicism is sporadic. We report two paternal half-brothers affected with pigmentary mosaicism of the hyperpigmented type. The hyperpigmentation in both patients is distributed along the lines of Blaschko. In addition, mental retardation, facial asymmetry, short stature, scoliosis, and short fingers with clinodactyly of the 5th digit were noted in one of them. Chromosome analysis in this 15-year-old patient demonstrated a mosaic 46,XY,dup(3)(p21.3;pter)/46,XY with 12% aberrant cells in lymphocytes and 2% in skin fibroblasts derived from a hyperpigmented area. His nine-year-old half-brother had similar systematized hyperpigmented skin lesions, macrocephaly, facial asymmetry, and clinodactyly of the 5th digit. Chromosome analysis of peripheral lymphocytes showed a normal karyotype 46,XY. A skin biopsy could not be obtained. So far, some familial cases of hypopigmentation along the lines of Blaschko have been reported, but familial occurrence of the hyperpigmented type of pigmentary mosaicism appears to be extremely unusual. It is difficult to establish a causal relationship with the chromosomal mosaicism as observed in patient 1. Paradominant transmission seems unlikely because this would likewise imply that the chromosomal mosaicism is an incidental finding.     

47,XX,+der(18),t(9;18)(p24;q21) mat: a distinct partial trisomy 18q--syndrome?

A moderately retarded girl had a 47,XX,+der(18),t(9;18)(p24;q21)mat abnormality that was inherited from her mother, who had a 46,XX,t(9;18)(p24;q21) karyotype in most cells, and a minor cell line of 47,XX,+der(18),-t(9;18)(p24;q21). Her dysmorphic features--bilateral epicanthic folds, low-set, abnormal ears, low posterior hairline, clinodactyly of the 5th fingers, and broad great toes--were similar to those of other patients with an additional number 18 chromosome in which all or most of the long arm was missing, thus raising the possibility of a distinct syndrome.     

Turner Phenotype: Mosaic 45,X/47,XY,+18

A 14-year-old girl with Turner phenotype is described, whose lymphocyte and skin fibroblast cultures both revealed a 45,X/47,XY,+18 chromosomal mosaicism. In blood cultures one third and in fibroblasts 7% of the cells had 47 chromosomes. The identity of the Y and the supernumerary 18 were determined by fluorescence and Giemsa banding patterns. The patient is of normal intelligence and does not exhibit any signs of masculinization or stigmata of trisomy 18.     

Cytogenetics of recurrent abortions

G-banded chromosome complements were analysed from both partners of 150 couples who had had two or more spontaneous abortions. Two women and four men were found to be balanced translocation carriers, as follows: 46, XX, t(2;10), 46, XX, t(6;II), 46, XY, t(6;10), 45, XY, t(13;14), 45, XY, t(13;14). 45, XY, t(14;21). Another woman had an abnormal karotype 46, XX/47, XXX and a man had a pericentric inversion of chromosome 1; six other men and two women had pericentric inversions of chromosome 9.     

Pigmentary mosaicism of the hyperpigmented type in two half‐brothers

Pigmentary mosaicism is a heterogeneous cutaneous phenotype that is often associated with extracutaneous anomalies. It is widely accepted that these phenotypes arise de novo as a result of a postzygotic mutation, leading to a mosaic status of the embryo. In the vast majority of cases, the occurrence of pigmentary mosaicism is sporadic. We report two paternal half‐brothers affected with pigmentary mosaicism of the hyperpigmented type. The hyperpigmentation in both patients is distributed along the lines of Blaschko. In addition, mental retardation, facial asymmetry, short stature, scoliosis, and short fingers with clinodactyly of the 5th digit were noted in one of them. Chromosome analysis in this 15‐year‐old patient demonstrated a mosaic 46,XY,dup(3)(p21.3;pter)/46,XY with 12% aberrant cells in lymphocytes and 2% in skin fibroblasts derived from a hyperpigmented area. His nine‐year‐old half‐brother had similar systematized hyperpigmented skin lesions, macrocephaly, facial asymmetry, and clinodactyly of the 5th digit. Chromosome analysis of peripheral lymphocytes showed a normal karyotype 46,XY. A skin biopsy could not be obtained. So far, some familial cases of hypopigmentation along the lines of Blaschko have been reported, but familial occurrence of the hyperpigmented type of pigmentary mosaicism appears to be extremely unusual. It is difficult to establish a causal relationship with the chromosomal mosaicism as observed in patient 1. Paradominant transmission seems unlikely because this would likewise imply that the chromosomal mosaicism is an incidental finding. © 2002 Wiley‐Liss, Inc.     

Maternal translocation (9;18) with two abnormal offspring each with different chromosome derivatives.

We report a phenotypically normal woman with an apparently balanced reciprocal translocation between chromosomes 9 and 18 [46,XX,t(9;18)(p22;p11.2)], giving rise to unbalanced chromosome complements in two of her children, each of whom received a different derivative chromosome. The proband's karyotype is 46,XY,-18,+der(18), t(9;18)(p22;p11.2)mat, which results in a duplication of the distal portion of the short arm of chromosome 9 with a concomitant deletion of much of the short arm of chromosome 18. The karyotype of the proband's brother is 46, XY,-9,+der(9),t(9;18)(p22;p11.2)mat, which results in a deletion of the distal short arm of chromosome 9 and a duplication of most of the short arm of chromosome 18. The phenotype of each child is significantly different from that of his sib and is not consistent with any previously reported chromosome abnormality.     

Trisomy 9 syndrome: Report of a case with Crohn disease and review of the literature

We report on a 6-year-old boy with mosaic trisomy 9. The patient was born at 42 weeks of gestation to a 27-year-old G1 white woman. Birth weight was 2,820 g, length 52 cm, and Apgar scores were 4 and 6 at 1 and 5 min, respectively. The infant presented with apparently low-set ears, overfolded helices, epicanthal folds, prominent nasal bridge, high-arched palate, micrognathia, bilateral dislocated hips, left genu recurvatum, and cryptorchidism. Chromosome analysis showed an unusual karyotype: 47,XY,+inv(9qh+)/47,XY,+mar. The marker chromosome was thought to be a remnant of the inv(9qh+) chromosome. The mother's karyotype was 46,XX,inv(9qh+), while the father's was 46,XY. At age 5 months, the patient developed seizures and gastroesophageal reflux. Crohn disease was diagnosed at age 2 years, although symptoms began at age 1 year. Recurrent bouts of pneumonia have occurred since the patient's birth. Severe psychomotor retardation was also noted. Trisomy 9 syndrome was first reported in 1973. Over 30 cases have been reproted since then. Of these case reports, only 5 patients were older than 1 year. Inflammatory bowel disease has been reported in association with other chromosome abnormalities, but to our knowledge, has not been reported in trisomy 9 syndrome. © Wiley-Liss, Inc.