Confirmation of regional assignment of nucleoside phosphorylase (NP) on chromosome 14 by gene dosage studies

Summary Gene dosage studies yielded results consistent with assignment of the locus for nucleoside phosphorylase to band 14q13. The red blood cells from a patient with the karyotype 47,XX,+der(14),t(8;14)(8qter8q24: :14q2114pter)pat had enzyme activity 50% higher than red cells from 47 normal controls, two trisomies involving chromosomes other than 14, and five balanced translocations involving chromosome 14. On the other hand, the red cells of a case with a karyotype 45,XX,-14,-22,+der(22),t(14;22)(14qter14q11 or 14q12::22p1122qter)mat and a case with a karyotype 47,XX, +der(14),t(14;16)(14pter14q11::16q2416qter)mat had normal activity.     

An XX male with a 46,XX/47,XX,+Y(q12→qter) karyotype

Summary We describe a male with the karyotype 46,XX/47, XX,+Y(q12qter), which may be interpreted as due to an insertion (Y;X)(Yq11Yq12;Xp22) or to mosaicism, 46,XX/47, XX,+Y(12qter). In any case, some of the H-Y determining genes may be located on the long arm of the Y chromosome.     

Supernumerary marker chromosomes in peripheral blood cells of hepatitis B virus chronic carriers

Cytogenetic analysis of metaphase chromosome spreads from peripheral blood cells of hepatitis B virus (HBV) chronic carriers revealed supernumerary marker chromosomes in 2 of the 46 individuals tested. Both individuals are phenotypically normal oriental males, and exhibit mosaicism with a 46,XY/47,XY,+mar/ 48,XY,+2mar profile in one, and a 46,XY/47,XY,+mar profile in other. Based on the reported frequency of unidentified supernumerary chromosomes (12,500) in 377,357 amniocentesis samples, the frequency seen (123) in the population of HBV chronic carriers sampled here appears unusually high. The possibility of a role for HBV in the generation of marker chromosomes is discussed.     

Double autosomal/gonosomal mosaic aneuploidy: study of nondisjunction in two cases with trisomy of chromosome 8

We report cytogenetic and molecular investigations performed in two cases of mosaic trisomy 8 combined with mosaic sex chromosome aneuploidy. In a 35-year-old female, presenting with short stature, gonadal dysgenesis, and a multiple congenital anomalies/mental retardation syndrome typical of trisomy 8, chromosome analysis from peripheral lymphocytes showed the presence of three cell lines, whose karyotypes were 45,X (59.2%), 46,X,+8 (1.2%), and 47,XX,+8 (39.6%), respectively. The same cell lines were found in a skin fibroblast culture, though in different proportions. The second patient, a 9-month-old male with multiple skeletal abnormalities, showed a 47,XY,+8 and a 47,XXY cell line in both peripheral lymphocytes (61.7% and 38.3%, respectively) and skin fibroblasts (92.8% and 7.2%, respectively). To determine the events underlying the origin of these complex karyotypes we performed Southern blot and polymerase chain reaction (PCR) analysis using polymorphic DNA markers from the X chromosome and from chromosome 8. Both supernumerary chromosomes 8, and, in case 2, the two X chromosomes, appeared to be identical, lacking detectable recombination events. We conclude that, in both cases, the most likely mechanism underlying the origin of the mosaic cell lines was formation of a normal zygote, followed by mitotic errors during early divisions.     

A cytogenetic survey of 200 unclassifiable mentally retarded children with congenital anomalies and 200 normal controls

Summary A cytogenetic survey was carried out on 200 patients with mental retardation and multiple congenital anomalies, and on 200 normal adult controls. Patients with a known syndrome were excluded from the survey. Chromosome analyses were carried out on blind-coded slides using the ASG banding technique as the routine stain. After the initial analyses (at least 15 cells per person) the slides were decoded, destained and reused for C and Q band polymorphism studies.Five major chromosome abnormalities were detected in the patient group during the survey. They included three patients with de novo, apparently balanced, reciprocal translocations, karyotypes 46,XY,rcp(3;16)(q21;p12); 46,XX,rcp(5;8)(p15;q22); and 46,XX,rcp(5;12)(p11;q24); one with karyotype 47,XX,+mar and one with karyotype 46,XX,der(13),t(13;?)(q34;?). One additional patient whose karyotype in lymphocytes was 46,XX,inv(9)(p11;q13) was found to have a mosaic karyotype 46,XX,inv(9)(p11;q13)/46,XX,inv(9) (p11;q13),der(12),t(12;?)(p13;?) in cultured skin fibroblasts. None of the 200 controls had a major chromosome abnormality.From the combined results of this and previous surveys it is now apparent that about 6.2% of the unclassifiable mentally retarded patients with three or more congenital anomalies and about 0.7% of the controls reveal major chromosome abnormalities.     

First small supernumerary ring chromosome carrying 10q euchromatin in a patient with mild phenotype characterized by molecular cytogenetic techniques and review of the literature

We report the identification and characterization of the first supernumerary ring chromosome 10 containing a considerable proportion of 10q euchromatin by microdissection and reverse painting in a female patient presenting with short stature. Fluorescence in situ hybridization studies showed that the marker chromosome originates from chromosome 10 and includes the euchromatic bands p11.2 and q11.2. The supernumerary marker chromosome 10 was found in 14% of the peripheral blood lymphocytes analyzed. This constitutional mosaic could be confirmed in oral mucosa cells as a second cell system (16%) by interphase FISH using an alphoid centromeric probe for chromosome 10. Parental karyotypes were normal, uniparental disomy for the normal chromosomes 10 could be excluded by microsatellite analysis. The karyotype of the patient detected in peripheral blood cells can be described as mos 47,XX,+mar.rev ish r(10)(p11.2q11.2)(wcp10+,cep10+)/46,XX.     

Increased incidence of hyperhaploid 24,XY spermatozoa detected by three-colour FISH in a 46,XY/47,XXY male

Meiotic segregation of gonosomes from a 46,XY/47,XXY male was analysed by a three-colour fluorescence in situ hybridisation (FISH) procedure. This method allows the identification of hyperhaploid spermatozoa (with 24 chromosomes), diploid spermatozoa (with 46 chromosomes) and their meiotic origin (meiosis I or 11). Alpha satellite DNA probes specific for chromosomes X, Y and 1 were observed on 27,097 sperm nuclei. The proportions of X-and Y -bearing sperm were estimated to 52.78% and 43.88%, respectively. Disomy (24,XX, 24,YY, 24,X or Y,+1) and diploidy (46,XX, 46,YY, 46,XY) frequencies were close to those obtained from control sperm, whereas the frequency of hyperhaploid 24,XY spermatozoa (2.09%) was significantly increased compared with controls (0.36%). These results support the hypothesis that a few 47,XXY germ cells would be able to complete meiosis and to produce mature spermatozoa.     

Supernumerary small marker chromosome (SMC) and uniparental disomy 22 in a child with confined placental mosaicism of trisomy 22: trisomy rescue due to marker chromosome formation

Trisomy rescue is one of various proposed mechanisms in formation of supernumerary small marker chromosomes (SMC) and uniparental disomy (UPD). In the present report a small de novo marker chromosome derived from chromosome 14 or 22 was diagnosed at prenatal diagnosis due to maternal age. Follow up investigations at birth revealed mosaicism 47,XX,+mar/46,XX. Using FISH, the marker was positive for the probe D14/22Z1, but negative for the probes midi 54 and D22Z4. Using three informative markers both chromosomes 22 were shown to be inherited from the mother (UPDmat). The results are consistent with nondisjunction at maternal meiosis I. The girl is 18 months old now and phenotypically normal. Cardiac and abdominal malformations were excluded by sonographic examinations. Motor and mental development is according to or ahead of developmental milestones (free walking with 10 months, first words at 12 months). The case confirms that maternal UPD 22 most likely is not associated with clinical abnormalities. According to FISH results, UPD 22, and 47,XX,+22 in the placenta, we conclude that the SMC was derived from alpha satellite sequences of chromosome 22. This case for the first time gives evidence that early postzygotic reduction of a chromosome to a small marker chromosome is a real existing mechanism to rescue a conceptus with trisomy.     

A case of r(21) with stigmata of atypical Down syndrome

Summary A case of r(21) with stigmata of atypical Down syndrome is presented. Karyotype of the proposita was determined as 45,XX,-21/46,XX,-21, +r(21)/47,XX,-21,+r(21),+(21). Most ring chromosomes showed double-sized ring chromosomes, which were trisomic for 21p11-21q22.3 and monosomic for 21q22.3-qter. SOD-1 activity revealed only slight elevation. The mechanism of ring formation is discussed.     

Transposition of c-abl oncogene in a case of masked Ph chromosome duplicated in blastic phase

Summary A female with chronic myelocytic leukemia (CML) in blastic phase (BP) showed a masked Ph chromosome that had originated by a translocation between chromosomes 8 and 22, with no obvious involvement of chromosome 9. A duplication of the masked Ph and trisomy 13 were present as additional anomalies. The karyotype on peripheral blood unstimulated cultures was 48,XX,t(8;22)(p12;q11),+13,+der(22) t(8;22)/47,XX,t(8;22)(p12;q11),+der(22)t(8;22). While the duplication of the Ph is a frequent finding in BP of CML, we did not find any other case in the literature with duplication of a masked Ph. In situ hybridization with c-abl and bcr probes showed that a 3 bcr sequence was translocated to the der(8) chromosome, while the c-abl oncogene was transposed to the masked Ph.     

Chromosomes 17 and 22 involved in marker formation in neurofibrosarcoma in von Recklinghausen disease

Summary We describe the cytogenetic findings in a recurrent neurofibrosarcoma in a patient with nonfamilial von Recklinghausen disease. The composite karyotype was: 40,Y,-X,+dic r(X;20)(:Xp22.2q26::20p13 q13:), -1, +der(1)t(1;3) (p21;p24),-3,-4,-5,+der(5) t(5;?)(q31;?),-9,-9,+der(9)t(3;9)(q21 or q13;p24 or p22), -11,+der(11)t(11;?)(q22.2;?), -17,+der(17)t(17; 22;?)(q21;q13.1;?), -20, -21, -22, -22, +der(22)t(17; 22;?)(q21;q13.1;?),t(2;10)(q37;q22). The derivative chromosomes were demonstrated at the 500 band level. Chromosomes 17 and 22 were shown to be involved in an unbalanced three-way translocation: t(17;22;?)(q21;q13.1;?). This event was confirmed by in situ hybridization, using two probes mapped to chromosome 17. Hill H is a probe derived from the novel oncogene TRE and is located at 17q12–22. The second probe, derived from the granulocyte colony-stimulating factor (G-CSF), is located at 17q11–q21. The rearrangement between chromosomes 17 and 22 showed breakpoints similar or close to the gene loci for neurofibromatosis 1 (NF-1) and NF-2. Based on our observations we recommend that genetic studies on NF-1 tumors include both gene sites (NF-1 and NF-2) rather than focus on one gene locus.     

Cytogenetic and molecular characterization of a newly established neuroblastoma cell line LS

Summary A new human neuroblastoma cell line (LS) that originated from an abdominal tumor of a 16-month-old girl is presented; it was classified, according to Evans, as being stage III. Morphological (dense-core particles) and biochemical characteristics (dopamine--hydroxylase, acetylcholinesterase, neuron-specific-enolase) confirmed the diagnosis. In addition to a slightly variable modal chromosome number of 48 or 49 (because of marker-chromosomes and autosomal trisomies), cytogenetic analysis revealed two constantly appearing chromosomes with homogeneously stained regions (HSR's). The karyo-type remained constant over 50 passages in vitro [49,XX, –12,+der5, + 17,+mar1,+mar2]. Double minutes were a rare phenomenon and appeared only in a few metaphases. In situ hybridization showed that some of the HSR's consisted of amplified N-myc copies. The distribution of the N-myc copies according to in situ hybridization signals along the HSR's was compared with the data of Southern and Northern blotting analyses.     

An attempt to establish trisomy 8 syndrome

Summary The techniques of H³-thymidine autoradiography, C and G bandings were utilized for the identification of an extra C chromosome in a patient with 47,XX,+C complement. The abnormal element was found to be an additional homolog of 8 pair. The clinical findings of this patient were compared with those cases that have been reported in the literature as 8 trisomies. A few more such cases must be studied before trisomy 8 syndrome can be established.

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Zusammenfassung Die Techniken der H³-Thymidin-Autoradiographie sowie der C- und G-banding-Methode wurden für die Identifizierung eines zusätzlichen C-Chromosoms bei einem Patienten mit einem Chromosomensatz von 47,XX,+C herangezogen. Das abnorme Chromosom stellt ein zusätzliches Homolog des Chromosomenpaares 8 dar. Die klinischen Befunde beim Patienten werden mit anderen Fällen, die in der Literatur beschrieben worden sind, verglichen. Bevor jedoch das Trisonomie 8-Syndrom charakterisiert werden kann, sind weitere Beobachtungen erforderlich.

     

Possible complex translocation t(9; 14; 13)(q12;pl?;q31) in mother of a child with 9p-trisomy syndrome

Summary A mentally retarded boy with trisomy 9p is described. This trisomy arose through aberrant segregation of translocation chromosome during meiosis in his mother, who has a complex translocation involving chromosomes 9, 13, and 14. Based on both G-, Q-banding, and DNA replication patterns, the patient's karyotype was identified as 47,XY,-13, +(9;13) (9pter9q12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter). We suppose his mother's karyotype to be 46,XX,-9,-13,-14,+t(9;13) (9pterq12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter), +t(9;14) (9qter9q12::14pl?14qter). His phenotypically normal brother and sister are also carriers, having the same translocation chromosome as their mother. Clinical findings of the patient included peculiar face with hypertelorism, prominent nasal bridge and deformed helix, marked delay of osseous development, hypoplastic phalangia in fingers and toes, dysplastic nails and absence of digital triradii.     

Genetics and biology of human ovarian teratomas. I. Cytogenetic analysis and mechanism of origin.

One hundred and two benign, mature ovarian teratomas and two immature, malignant teratomas were karyotyped and scored for centromeric heteromorphisms as part of an ongoing project to determine the chromosomal karyotype and the genetic origin of ovarian teratomas and to assess their utility for gene-centromere mapping. Karyotypic analysis of the benign cases revealed 95 46,XX teratomas and 7 chromosomally abnormal teratomas (47,XXX, 47,XX,+8 [two cases], 47,XX,+15, 48,XX,+7,+12 91,XXXX,-13 [mosaic], 47,XX,-15,+21,+mar). Our study reports on the first cases of tetraploidy and structural rearrangement in benign ovarian teratomas. The two immature cases had modal chromosome numbers of 78 and 49. Centromeric heteromorphisms that were heterozygous in the host were homozygous in 65.2% (n = 58) of the benign teratomas and heterozygous in the remaining 34.8% (n = 31). Chromosome 13 heteromorphisms were the most informative, with 72.7% heterozygosity in hosts. The cytogenetic data indicate that 65% of teratomas are derived from a single germ cell after meiosis I and failure of meiosis II (type II) or endoreduplication of a mature ovum (type III); 35% arise by failure of meiosis I (type I) or mitotic division of premeiotic germ cells (type IV).     

Rare case of XX/XY mosaicism and trisomy 13 in early prenatal diagnosis

Coexistence of XX/XY sex mosaicism and autosomal trisomy in prenatal diagnosis is particularly rare. Herein, we report the first, to our knowledge, case of a fetus with cyclopia, ambiguous genitalia and a 47,XX,+13,inv9[47]/47,XY,+13[13] karyotype detected at 13 weeks of gestation after chorionic villus sampling. Molecular analysis after prenatal diagnosis suggests that this is a case of sex mosaicism coexisting with trisomy 13, rather than chimera.     

Cytogenetic studies of familial Prader-Willi syndrome

Summary A family in which two first cousins were found to have the Prader-Willi syndrome was investigated cytogenetically. Although G-banding analysis of metaphase chromosomes failed to demonstrate abnormality, close analyses on the fine prometaphase bands by G-banding and the DA-DAPI bands by double stainings revealed a distinct chromosome abnormality in this family. A reciprocal translocation, rep(14:15)(q11.2;q13), was detected in three family members: the mother, the maternal grandmother, and a maternal uncle of the proband. And, the proband and one of the first cousins had an unbalanced translocation that was derived from their carrier parents. The karyotypes of the affected cousins were determined as 46,XY or XX,-15,+der(14),rcp(14;15)(q11.2;q13). Therefore, they were considered to have an identical cytogenetic abnormality: a partial trisomy of the 14pterq11.2 segment and a partial monosomy of the 15pterq13 segment. Detailed clinical features of the proband and his affected cousin are described, main features associated with the Prader-Willi syndrome having been observed in both cousins. These observations support a definite relationship between the Prader-Willi syndrome and chromosome 15.     

Free trisomy 9P in elderly woman.

The karyotype 47,XX,+9p was observed in a 50-year-old mentally retarded woman with dysmorphic facies, severe cerebral malformations, limb deformities, retarded sexual maturation and deviating dermatoglyphs. Banding analysis showed the extra chromosome to be composed of 9p and the proximal part of 9q comprising a large secondary constriction. The breakage point is estimated as 9q13. Hemozygous large C bands were observed in both chromosomes No. 9 as well as in the extra chromosome. Clinically this case can be regarded as a pure 9p trisomy. The mechanism causing the syndrome is thought to be malsegregation of a deleted chromosome No. 9.     

46,X,i(Xq)/47,XX,+13 mosaicism

A 10-year-old girl with short stature and other features of Turner's syndrome was found to be a mosaic consisting of 46,X,i(Xq) and 47,XX,+13 cell lines, a hitherto undescribed situation. She had none of the clinical features of trisomy 13 syndrome, with a possible exception of postaxial polydactyly of the left foot. Her PHA-stimulated blood lymphocytes and EB virus-transformed B lymphocytes both revealed the Xi(Xq)/XX,+13 mosaicism, while her skin fibroblasts showed an exclusively 46,X,i(Xq) karyotype. Studies using Q-and R-banding heteromorphisms as markers indicated that the patient started as a 13 trisomic zygote resulting from a maternal meiotic error, followed by the loss of chromosome 13 at an early mitotic division. C-banding analysis revealed two C banding blocks in the iso X chromosome, an indication that the chromosome was dicentric. BrdU-Hoechst-Giemsa analysis revealed that the iso X chromosome was late-replicating with both its arms either synchronously or asynchronously replicating. The iso X chromosome was thus designated as idic (Xq)(p11:p11). In view of the presence of the XX cell line, it was concluded that the patient started as an XX,+13 zygote, followed by two mitotic events, the loss of a chromosome 13 and the formation of the iso X chromosome, occurring either simultaneously or in succession.     

Mosaic trisomy 9: Two additional cases

Summary Two unrelated patients were found to be mosaic for an extra chromosome 9 (46,XX/47,XX,+9). The first patient showed a prominent nose, deep set eyes, carp shaped mouth and complex congenital cardiac anomalies. She died of congestive cardiac failure at the age of 10 days. The second patient, was a 7 1/2 year old female who had persistent alacrimia and mental retardation.