Prenatal diagnosis and molecular cytogenetics in a case of partial trisomy 14 and monosomy 21

We report an unbalanced translocation involving chromosomes 14 and 21 which presented as fetal ventriculomegaly at 33 weeks gestation. Second trimester ultrasound had indicated normal fetal anatomy, including normal intracranial structures. Parental karyotypes showed a paternal balanced translocation: 46,XY,t(14;21)(q12;q21). The unbalanced translocation in the fetus resulted in trisomy for 14pter-->q12 and monosomy for 21pter-->q21. Postnatal examination showed that the male infant had a cleft palate, but no cleft lip, and mild dysmorphic features. Postnatal MRI revealed bilateral and symmetric dilatation of the occipital horns, atria, and temporal horns of the lateral ventricles. Molecular cytogenetic techniques were used to delineate further the breakpoint on chromosome 14 to a site distal of the D14S1071 locus and the breakpoint on chromosome 21 to a region between D21S1918 and D21S1902. More precise definitions of chromosomal breakpoints in such clinical cases should provide more accurate prognosis for individuals with unbalanced karyotypes and assist in the identification of putative developmentally important genes.     

Simultaneous partial monosomy 10p and trisomy 5q in a case of hypoparathyroidism.

We report a case of monosomy for the distal region of the short arm of chromosome 10 (p13----ter) associated with trisomy for the terminal region of the long arm of chromosome 5 (q35.2----ter) that had originated from adjacent 1 segregation of a maternal reciprocal balanced translocation (5;10)(q35.2;p13). We review the clinical findings of previously reported cases of both partial monosomy for 10p and of partial trisomy for 5q, but to our knowledge there are no previous reports of the effects of these two chromosome anomalies together. Clinically our patient showed features typical of partial monosomy for 10p (including hypothyroidism) rather than partial trisomy 5q.     

Three children with partial trisomy 1q and partial monosomy 3p.

We report a kindred in which three children suffer from partial trisomy 1q and partial monosomy 3p, transmitted by a balanced translocation which is maternal in one family and paternal in the other. The clinical features of the three children are similar and include severe mental handicap and severe scoliosis in the older two.     

Normal phenotype and partial trisomy for the G positive region of chromosome 21.

A prenatally diagnosed male fetus and his mother, who was referred because of her advanced age, both carried an abnormal bisatellited chromosome 21 as an extra chromosome. The abnormal 21 was monocentric and the G negative band q22 and part of q21 had been deleted during formation. The phenotype of both the mother and child (at birth) was normal.     

Severe mental retardation in a boy with partial trisomy 10q and partial monosomy 2q.

A severely mentally subnormal child with many physical stigmata was shown to have the karyotype 46,XY,-2,+der(2),t(2;10)(q31;q24)pat. Full evaluation of this patient's karyotype depended on the family studies. It was shown that a balanced translocation t(2,10) was present in 4 normal males in 3 generations.     

A case of apparent trisomy 21 without the Down''s syndrome phenotype.

We describe a case of apparent trisomy 21 that does not fulfill the criteria for the clinical diagnosis of Down's syndrome (DS). Our patient was subjected to karyotype analysis and found to have full, non-mosaic trisomy 21 in both blood lymphocytes and skin fibroblasts, while examination of the term placenta, which was performed earlier in the course of a different study, had shown mosaicism (73%) for trisomy 21. FISH analysis showed no obvious rearrangement of the DS chromosomal region in any of the chromosomes 21. Molecular analysis using polymorphic markers on chromosome 21 verified the existence of trisomy for the entire long arm of the chromosome and showed that the origin of the extra chromosome was maternal and was probably the result of a mitotic error. In contrast with the above, the clinical evaluation using the Jackson checklist of 25 signs failed to establish the diagnosis of DS. We believe that our patient might present mosaicism in other tissues that are not available for analysis and can be regarded as an extreme example in the continuous spectrum of karyotype phenotype associations in mosaic cases.     

A case of partial monosomy 21q22.2 associated with Rieger''s syndrome.

A deleted chromosome 21 is reported in a mentally retarded girl with prominent occiput, high nasal bridge, downward slanting eyes, enophthalmus, atresia of the right lacrimal duct, displaced anal opening, and supernumerary ribs. Cytogenetic investigation of cultured lymphocytes and skin fibroblasts revealed a deletion of the long arm of chromosome 21 at sub-band q22.2 with satellites on both arms. Normal SOD-1 activity confirmed the breakpoint to be distal to band q22.1.     

Partial monosomy 13q and partial trisomy 18p: case report with necropsy findings.

We describe a stillborn female infant with severe intrauterine growth retardation and multiple congenital anomalies. She was found to have a deletion of 13q22----qter and trisomy of 18p11.2----pter, resulting from a maternal balanced translocation.     

Fryns syndrome phenotype and trisomy 22

Trisomy 22 was detected in a 32-week-old fetus born to an overweight mother with hypertension. Severe intrauterine growth retardation was associated with phenotypic manifestations of Fryns syndrome: diaphragmatic hernia, facial defects, and nail hypoplasia with short distal fifth phalanges. This is the second report of congenital diaphragmatic hernia in trisomy 22. This case demonstrates the importance of karyotyping malformed fetuses or newborns, even if a nonchromosome syndrome seems identifiable on clinical grounds. To date, at least 10 cases of Fryns syndrome have been reported without chromosome analysis. © 1996 Wiley-Liss, Inc.     

一例1q部分三体4q部分单体导致Pierre Robin序列征的遗传学分析

目的:对1例临床诊断为Pierre Robin序列征的患儿进行细胞及分子遗传学分析,寻找遗传学病因。方法:应用外周血染色体核型分析、核苷酸多态性微阵列检测和荧光原位杂交技术,分别对1例表型为下颌小、舌后坠、上呼吸道阻塞、上颚裂开、颈短的患儿及其正常表型的父母进行检测。结果:患儿核型为46,XY,der(4)add(4)...     

Unusual phenotype in partial trisomy 14

An 8-year-old boy with partial trisomy 14q and phenotype distinct from previously reported cases is described. The mother carries a balanced 9;14 reciprocal translocation. The patient presented with minor facial anomalies, developmental delay, hyperphagia, and obesity. Imprinting of maternal chromosome 14 or disruption of one or more genes on chromosome 9 may be responsible for our patient's manifestations.     

一4q部分三体10q部分单体患儿的分子细胞遗传分析

目的 确定一生长迟缓、智力低下患儿的核型,分析其染色体变异与表型的相关性,同时探讨微阵列比较基因组杂交(array-based comparative genomic hybridization,array-CGH)在临床分子细胞遗传诊断中的应用及其优越性.方法 应用G显带染色体分析、array-CGH、荧光原位杂交(fluorescence in situ hybridization,FISH)和实时定量PCR(real-time quantitative PCR,RQ-PCR)对患儿及其亲属进行核型分析.结果 G显带染色体分析显示患儿存在1条来源于父亲的10号衍生染色体der(10)t(4;10)(q25;q26),其父亲和祖母均是t(4;10)(q25;q26)平衡易位携带者.Array-CGH显示患儿存在4q26-q35.2三体,并将断裂点定位于4q26,此外,还发现患儿10号染色体存在一约0.54 Mb的微缺失del(10)(q26.3).FISH和RQ-PCR证实父亲和祖母也存在del(10)(q26.3).结论 del(10)(q26.3)并不导致表型异常,患儿的异常表型可归因于4q26-q35.2三体.与传统的细胞遗传分析方法 相比,array-CGH具有高分辨率和高准确性等优点.     

一4q部分三体10q部分单体患儿的分子细胞遗传分析

目的 确定一生长迟缓、智力低下患儿的核型,分析其染色体变异与表型的相关性,同时探讨微阵列比较基因组杂交(array-based comparative genomic hybridization,array-CGH)在临床分子细胞遗传诊断中的应用及其优越性.方法 应用G显带染色体分析、array-CGH、荧光原位杂交(fluorescence in situ hybridization,FISH)和实时定量PCR(real-time quantitative PCR,RQ-PCR)对患儿及其亲属进行核型分析.结果 G显带染色体分析显示患儿存在1条来源于父亲的10号衍生染色体der(10)t(4;10)(q25;q26),其父亲和祖母均是t(4;10)(q25;q26)平衡易位携带者.Array-CGH显示患儿存在4q26-q35.2三体,并将断裂点定位于4q26,此外,还发现患儿10号染色体存在一约0.54 Mb的微缺失del(10)(q26.3).FISH和RQ-PCR证实父亲和祖母也存在del(10)(q26.3).结论 del(10)(q26.3)并不导致表型异常,患儿的异常表型可归因于4q26-q35.2三体.与传统的细胞遗传分析方法 相比,array-CGH具有高分辨率和高准确性等优点.     

An unusual combination of trisomy 21 and partial trisomy 5q.

The authors describe a male newborn with multiple congenital anomalies; craniofacial dysmorphism, bilateral cleft palate and lip, ambiguous external genitalia with absence of phallus, ventricular septal defect, agenesis of olfactory bulbs, and presence of small round cells simulating migration defect in the cerebellar white matter. Cytogenetic study demonstrated a chromosomal constitution of 47,XY, +21, +5q. Its pathological significance compared with Down's syndrome and hitherto reported partial trisomy 5q is discussed.     

一4q部分三体10q部分单体患儿的分子细胞遗传分析

目的 确定一生长迟缓、智力低下患儿的核型,分析其染色体变异与表型的相关性,同时探讨微阵列比较基因组杂交(array-based comparative genomic hybridization,array-CGH)在临床分子细胞遗传诊断中的应用及其优越性.方法 应用G显带染色体分析、array-CGH、荧光原位杂交(fluorescence in situ hybridization,FISH)和实时定量PCR(real-time quantitative PCR,RQ-PCR)对患儿及其亲属进行核型分析.结果 G显带染色体分析显示患儿存在1条来源于父亲的10号衍生染色体der(10)t(4;10)(q25;q26),其父亲和祖母均是t(4;10)(q25;q26)平衡易位携带者.Array-CGH显示患儿存在4q26-q35.2三体,并将断裂点定位于4q26,此外,还发现患儿10号染色体存在一约0.54 Mb的微缺失del(10)(q26.3).FISH和RQ-PCR证实父亲和祖母也存在del(10)(q26.3).结论 del(10)(q26.3)并不导致表型异常,患儿的异常表型可归因于4q26-q35.2三体.与传统的细胞遗传分析方法 相比,array-CGH具有高分辨率和高准确性等优点.