1/23. prenatal diagnosis of dyssegmental dysplasia. A case report.BACKGROUND: Since the first use of sonography, most fetal dwarfism has been detectable prenatally. The correct differentiation of the subtype of dwarfism is difficult at times. Dyssegmental dysplasia is probably an exception to these subtypes because the vertebral disorganization and occipital encephalocele at times permits prenatal diagnosis. CASE: A 34-year-old woman, gravida 3, para 1, elective abortion 1 for dwarfism, was referred at 27 weeks' gestation for cystic hygroma. Further sonographic findings included: cystic hygroma with massive ascites, micromelia, occipital encephalocele, spinal disorganization and hydramnios. The fetus and both parents appeared to have a normal karyotype. Later the pregnancy was terminated with vaginal delivery. The fetus had micromelia, camptomelia, cystic hygroma, a flat face, short neck, short trunk, narrow thorax with protuberant abdomen, scoliosis and clubfeet. CONCLUSION: Sonography is effective in prenatal diagnosis of dyssegmental dysplasia. With sonography, diagnosis of dyssegmental dysplasia becomes possible as early as the first trimester.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
2/23. Isochromosome consisting of terminal short arm and proximal long arm X in a girl with short stature.A 16-year-old girl with short stature, short neck, shield chest, and cubitus valgus was studied. FISH analyses of her structurally altered X chromosome showed a der(X)- (wcpX ,TelXp/Yp ,SHOX ,STS ,KAL-, 37A12-,DXZ1 ,XIST ,97L7 ,300O13-,404F- 18-,417G15-,404F18-,140A-,TelXq/Yq-). These results, together with the high-resolution banding analysis, indicated her karyotype to be 46,X,der(X)(Xpter-->Xp22.3::Xq22.3--> cen-->Xq22.3::Xp22.3-->Xpter). The der(X) was an isochromosome, consisting of duplicated terminal short arms and duplicated proximal long arms. This in turn suggested that the chromosome was formed through pericentric inversion of an X chromosome, followed by isochromosome formation through sister chromatid exchange at Xp, close to the centromere. Replication R-banding analysis showed that the abnormal X chromosome was late replicating. Analysis of digestion patterns with a methylation-sensitive restriction endonuclease of the phosphoglycerate kinase 1 gene, located in Xq13.3, indicated that its inactivation patterns were completely skewed.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
3/23. Craniofacial anomalies, deafness, brachydactyly, short stature, and moderate mental retardation due to a cryptic 6p;11q translocation.Monozygotic twin brothers are described who share clinical features which include: moderate mental retardation, short stature, macrocephaly, frontal bossing, ptosis, low-set ears, brachydactyly, 5th fingers clinodactyly, single palmar creases, cryptorchidism, and prelingual sensorineural deafness. One of the twins presented with mild cardiac dilatation and died at age 3(1/2) from cardiac arrest during an episode of acute respiratory infection. While chromosome analyses performed for both twins on peripheral blood showed apparently normal karyotypes, screening for all telomeric regions on the surviving propositus revealed a combination of partial 6p trisomy and partial 11q monosomy. A balanced reciprocal translocation was found in the father. The phenotype of the twins is most likely related to this cryptic chromosomal rearrangement. The fact that the phenotype in this family partially overlaps with some previously reported phenotypes is discussed.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
4/23. Lack of expression of XIST from a small ring X chromosome containing the XIST locus in a girl with short stature, facial dysmorphism and developmental delay.A 46,X,r(X) karyotype was found in a three and a half year old girl with short stature, facial dysmorphism and developmental delay. The clinical findings were consistent with the phenotype described in a limited number of patients with small ring X chromosomes lacking the XIST locus, a critical player in the process of x chromosome inactivation. Surprisingly, in our patient, fluorescent in situ hybridisation demonstrated that the XIST locus was present on the ring X. However, expression studies showed that there was no XIST transcript in peripheral blood cells, suggesting that the ring X had not been inactivated. This was confirmed by the demonstration that both of the patient's alleles for the androgen receptor gene were unmethylated, and that both of the patient's ZXDA alleles were expressed. The active nature of the ring X would presumably result in overexpression of genes that may account for the developmental delay observed for the patient. Using polymorphic markers along the X chromosome, the ring X was determined to be of paternal origin with one breakpoint in the long arm between DXS8037 and XIST and one in the short arm in Xp11.2 between DXS1126 and DXS991. To attempt to determine why the XIST gene failed to be expressed, the promoter region was sequenced and found to have a base change at the same location as a variant previously associated with nonrandom x chromosome inactivation. This mutation was not seen in over one hundred normal X chromosomes examined; however, it was observed in the paternal grandmother who did not show substantial skewing of x chromosome inactivation.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
5/23. Maternal isodisomy for 14q21-q24 in a man with diabetes mellitus.We report a 20-year-old man with maternal uniparental disomy for chromosome 14 (UPD14) and maturity-onset diabetes mellitus (DM). He had pre- and postnatal growth retardation, developed DM at age 20 years without any autoimmune antibodies, and had a mosaic 45,XY,der(14;14)(q10;q10)[129]/46,XY, 14,der(14;14)(q10;q10)[1] karyotype. Allelotyping using microsatellite markers covering the entire 14q indicated segmental maternal isodisomy for 14q21-q24 and maternal heterodisomy of the remaining regions of the chromosome. It is thus tempting to speculate that the segmental isodisomy led to reduction to homozygosity for a mutant gene and thus caused his DM, although the possibility of coincidental occurrence of the two events cannot totally be ruled out. fluorescence in situ hybridization (FISH) analysis using BAC clone probes revealed that the isodisomic segment did not overlap any known IDDM or NIDDM susceptibility loci on chromosome 14, suggesting a novel locus for a subset of DM at the isodisomic segment.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
6/23. An Xp; Yq translocation causing a novel contiguous gene syndrome in brothers with generalized epilepsy, ichthyosis, and attention deficits.PURPOSE: We describe two brothers with generalized epilepsy, attention deficits, congenital ichthyosis, and Leri-Weill dyschondrosteosis who harbor an unusual Xp; Yq translocation chromosome, resulting in a novel contiguous gene syndrome because of deletion of genes from the distal short arm of the X chromosome. methods: physical examination, neuropsychologic testing, EEG, and neuroimaging studies were performed. Because of their unusual phenotype, karyotyping, fluorescence in situ hybridization, and further molecular analyses were carried out to refine the break points of the underlying unbalanced sex chromosome rearrangement. RESULTS: The subjects had generalized epilepsy, X-linked ichthyosis, Madelung deformities, mesomelia, normal intelligence, and attention deficits. The brothers' karyotype was unbalanced; they inherited a maternal derivative X chromosome. Deleted distal Xp genes included short-stature homeobox on the X chromosome (SHOX), aryl sulfatase E (ARSE), variably charged X-chromosome mRNA gene A (VCX-A), and steroid sulfatase (STS). The final karyotype was 46,Y,der(X)t(X; Y)(p22.3; q11.2).ish der(X) (DXZ1 , KAL , STS-, SHOX-) mat. CONCLUSIONS: Loss of distal contiguous Xp genes resulted in a syndrome comprising bony deformities, ichthyosis, attention problems, and generalized epilepsy. Candidate epilepsy genes within the deleted segment, such as ASMT, a gene involved in the final synthesis of melatonin, are discussed. Cytogenetic analyses should be included in the clinical evaluation of patients with generalized epilepsy and complex phenotypes.- - - - - - - - - - ranking = 2keywords = karyotype (Clic here for more details about this article) |
7/23. Robinow syndrome in two siblings from consanguineous parents.A Kurdish family had two children affected with Robinow syndrome. The daughter had short stature, macrocephaly, hypertelorism, hepatosplenomegaly, short forearms and marked vertebral anomalies. Her brother had hypertelorism, hypertrophied alveolar ridges, hepatosplenomegaly, short forearms, rib anomaly and ambiguous genitalia. The karyotype of the affected male sibling showed mosaicism for 45X, 46,X,dicY(q11.22), 47,X,dicY(q11.22),dicY(q11.22).- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
8/23. Inherited ring chromosome 8 without loss of subtelomeric sequences.We report the first case of inherited ring chromosome 8 syndrome without loss of subtelomeric sequences. The proband is a 6 1/2-year-old boy with short stature, microcephaly, mild mental retardation, and behavioral problems including hyperactivity and attention deficit. His mother presented the same physical features but intelligence was normal. family history also revealed an uncle and a grandmother, with short stature and microcephaly. Moderate mental retardation was reported in the uncle. Karyotypes and fluorescence in situ hybridization (FISH) analyses were performed on peripheral blood lymphocytes for both child and mother. The child's karyotype was reported as 46,XY,r(8)(p23q24.3)[24]/45,XY,-8[2] and the mother's karyotype 46,XX,r(8)(p23q24.3)[22]/45,XX,-8[2]/47,XX,r(8)(p23q24.3), r(8)(p23q24.3)[1]. FISH studies showed no deletion of subtelomeric sequences for both child and mother indicating that no or little chromosomal euchromatic material has been deleted. These findings indicate that ring chromosome 8 without loss of subtelomeric sequences can be inherited and that carriers in a same family present with cognitive function ranging from mild mental retardation to normal intelligence.- - - - - - - - - - ranking = 2keywords = karyotype (Clic here for more details about this article) |
9/23. The silver-Russel syndrome: a case with sexual ambiguity, and a review of literature.A 38-month-old patient with silver-Russel syndrome (SRS) and ambiguous genitalia had a 46,XY karyotype on leukocyte and fibroblast cultures. This is the third SRS child with ambiguous genitalia described in the literature. In a review of the findings in 148 reported cases of the syndrome, abnormalities occurring in over 50% of the cases are short stature, craniofacial dysproportion, low birth weight, term gestation, body asymmetry, incurved fifth digits, normal intelligence, short fifth digits, and down-curved corners of the mouth (shark mouth).- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
10/23. Clinical outcome and follow-up of the first reported case of Russell-silver syndrome with the unique combination of maternal uniparental heterodisomy 7 and mosaic trisomy 7.BACKGROUND: Russell-silver syndrome (RSS) has been associated with maternal uniparental disomy (UPD) for chromosome 7 although the etiology of the syndrome is still unknown. Cases of RSS associated with maternal UPD7 have involved isodisomies, heterodisomies, and mixed isodisomy with heterodisomy simultaneously. This publication is a follow-up report of the postnatal clinical outcome of the first prenatally suspected case of combined mosaic trisomy 7 with maternal uniparental disomy of chromosome 7 (UPD7). CASE: The diagnosis of RSS in the proband was suspected prenatally because trisomy 7 mosaicism (47,XX, 7[13]/46,XX[19]) and maternal uniparental heterodisomy 7 were both found in amniotic fluid cells. Cord blood karyotype analysis showed only disomic cells (46,XX[50]), whereas postpartum chorionic villus analysis was completely trisomic for chromosome 7 (47,XX, 7[19]). Postnatally, the diagnosis of RSS was confirmed by physical findings, her trisomy 7 mosaicism was confirmed by cytogenetic analysis of her skin biopsy (47,XX, 7[9]/46,XX[20]) and her UPD7 was confirmed on both peripheral blood and skin biopsy using microsatellite markers. During infancy, the proband experienced growth deficiency, persistent hypoglycemia, and psychomotor developmental delay. CONCLUSIONS: Trisomic rescue as a life-saving mechanism, with subsequent chromosomal mosaicism in combination with UPD may occur more frequently in RSS than has been reported. Systematic testing of cases suspected prenatally or postnatally would be informative regarding the individual contribution of each factor. Imprinting, loss of heterozygosity for recessive genes, and mosaicism may explain the short stature, asymmetry, and the variable expression of the phenotype. The contribution of these mechanisms to the syndrome should be evaluated in these cases.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
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