1/9. trisomy 7p resulting from 7p15;9p24 translocation: report of a new case and review of associated medical complications.The authors report on a young girl with generalized developmental deficits originally thought to be caused by an unusual reaction to DPT vaccination. At the age of 4(1/2) years, chromosome analysis showed that the terminus of the short arm of chromosome 9 had extra material believed to originate from 7p terminus, thus she was considered to be trisomic for a segment of 7p and monosomic for a small portion of 9p [46,XX,der (9), t(7;9)(p15;p24)]. Ten years later, molecular cytogenetic testing using fluorescence in situ hybridization (FISH) confirmed that the extra chromosomal material represented partial trisomy 7p. The proposita had a high and large forehead, hypertelorism, and broad nasal bridge, findings seen in most individuals with trisomy 7p. Long-term follow-up showed the presence of hypothyroidism, obesity, and cerebral palsy. A review of all published cases of trisomy 7p with focus on associated complications suggests a well-defined pattern of abnormalities characterized by musculoskeletal, cardiovascular, neurological, genital, and ocular abnormalities in decreasing frequency. At least one-third of affected individuals died in infancy and close to half had severe mental retardation. FISH was essential in the confirmation of the cytogenetic abnormality and further delineation of the chromosomal disorder.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/9. Anisomastia associated with interstitial duplication of chromosome 16, mental retardation, obesity, dysmorphic facies, and digital anomalies: molecular mapping of a new syndrome by fluorescent in situ hybridization and microsatellites to 16q13 (D16S419-D16S503).Anisomastia is a common problem among developing adolescent girls. We recently evaluated a 22-yr-old female patient who had severe anisomastia (which had been repaired by surgery), associated with moderate to severe mental retardation, a stocky body habitus with mild obesity, dysmorphic facies (prominent, upslanting palpebral fissures, beaked nose, and a prominent philtrum), webbed neck, low hairline, and severe bilateral clinodactyly of the third, fourth, and fifth fingers with acral (but not large joint) flexion contractures. A peripheral blood high resolution karyotype revealed additional chromosomal material within the long arm of chromosome 16. Densitometric analysis of amplified polymorphic sequence-tagged sites (STS) mapping to 16q suggested that the duplication is defined by the noninvolved markers D16S419 [16q12-cen, 66 centimorgan (cM) from 16p terminus] and D16S421 (16q13-q21, 84.4 cM), encompassing a maximum of 18.4 cM of genetic distance. The STS analysis showed that the duplication was on the maternally derived chromosome 16, resulting in two maternal (and one paternal) copies of that region of chromosome 16. The location was further confirmed by bacterial artificial chromosomes (BACs) that were obtained from a commercially available library, labeled, and used for fluorescence in situ hybridization. The BACs containing STSs D16S408, D16S3137, and D16S3032 (markers that correspond to 16q13) showed two regions of hybridization, indicating that these sites were duplicated, whereas a BAC containing the STS D16S512 (which corresponds to 16q21-q22) revealed one hybridization signal per 16q, indicating that the corresponding region was not involved in the duplication. The distance between the probe signals suggested a tandem duplication. We conclude that even though trisomy 16 is the most common autosomal trisomy in spontaneous abortions, few patients with unbalanced chromosome 16 abnormalities survive to adulthood; in this report we describe one such patient with an interstitial chromosome 16 duplication (at 16q13), who had a specific phenotype associated with abnormal breast size. There are clinical similarities between this patient and patients with other 16q abnormalities, although the breast findings were unique. Molecular cytogenetics, including fluorescence in situ hybridization and densitometric analysis of amplified STSs, provided useful tools for the precise mapping of the syndrome to 16q13, where the gene(s) responsible for this phenotype might be localized.- - - - - - - - - - ranking = 8keywords = hybridization (Clic here for more details about this article) |
3/9. 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 = hybridization (Clic here for more details about this article) |
4/9. Interstitial deletion and ring chromosome derived from 19q. Proximal 19q trisomy phenotype.A small supernumerary ring chromosome has been found in a boy with overweight, dysmorphic facies and mental retardation. His mother had an interstitial deletion of the long arm of chromosome 19 and the same ring chromosome. By means of fluorescence in situ hybridization the ring chromosome was shown to be derived from the deleted chromosome, after the occurrence of two breaks: one in the centromere region, the other in the q-arm of chromosome 19.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/9. Characterization of mosaic supernumerary ring chromosomes by array-CGH: segmental aneusomy for proximal 4q in a child with tall stature and obesity.We report on a 6-year-old girl with developmental delay, tall stature, and obesity. G-banded chromosome analysis revealed mosaicism for one to three small de novo rings in 82% of peripheral lymphocytes. fluorescence in situ hybridization (FISH) studies and metaphase comparative genomic hybridization (CGH) demonstrated that the rings were derived from 4q10-4q13. A higher resolution investigation was initiated using array-CGH analysis and revealed a gain of 11 adjacent clones spanning a 16 Mb region at 4q11-q13.2 and including the insulin-like growth factor binding protein 7 (IGFBP7) gene. This finding suggests that postnatal overgrowth observed in our patient might be related to a dosage effect of the IGFBP7 gene.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
6/9. WAGR(O?) syndrome and congenital ptosis caused by an unbalanced t(11;15)(p13;p11.2)dn demonstrating a 7 megabase deletion by FISH.aniridia usually occurs in isolation, but may also occur as part of the WAGR contiguous gene deletion syndrome, which includes wilms tumor, aniridia, genitourinary abnormalities, and mental retardation. The aniridia and predisposition for wilms tumor seen in WAGR are caused by haploinsufficiency for PAX 6 and WT1, respectively. We present a female infant with aniridia, bilateral ptosis, bilateral posterior capsular cataracts, nystagmus, left-sided glaucoma, microcephaly, mild unilateral hydronephrosis, poor linear growth, and gross motor delay consistent with a clinical diagnosis of wagr syndrome. In addition, weight-for-height ratio at 12 months is at the 94th centile, raising the possibility of a diagnosis of WAGRO (WAGR obesity). Chromosome analysis revealed a translocation (11;15)(p13;p11.2) which has not been previously associated with a diagnosis of WAGR. Subsequent clinical WAGR fluorescent in situ hybridization (FISH) analysis demonstrated a deletion of 11p13 including PAX6 and WT1. A complete FISH-mapping of the breakpoints on chromosome 11 revealed a 7 Mb deletion within 11p13-11p14. The patient is examined in light of other reported patients with deletions and/or translocations involving the regions between 11p12 --> 11p14 including patients with WAGR obesity (WAGRO) as well as with other reported patients with aniridia and congenital ptosis.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/9. Abnormal processing of the human cholecystokinin receptor gene in association with gallstones and obesity.BACKGROUND & AIMS: cholesterol gallstone disease and obesity are often associated and share the potential, yet unreported, common etiology of cholecystokinin (CCK) dysfunction. While cloning the human CCK-A receptor complementary dna (cDNA), we found predominance of a 262-base pair coding region deletion in a cDNA library prepared from a patient with this phenotype. The aim of this study was to determine the abundance, functional significance, and mechanism for generating this gene product. methods: Relative abundance of CCK receptor gene products was determined using polymerase chain reaction and hybridization analysis. Constructs were expressed in cos cells and studied for radioligand binding and intracellular calcium responses. A human genomic clone for this receptor was sequenced, and the critical regions were compared with those of the patient. RESULTS: Ninety-three percent of the patient's CCK receptor transcripts contained the 262-base pair deletion, whereas only 1.5% /- 0.9% of control patients had the deletion. This encoded a receptor that did not bind or signal. The deletion corresponded with the third exon; however, this sequence and flanking introns were normal in the patient. CONCLUSIONS: Abnormality of processing an apparently normal CCK receptor gene yields the predominant product with an absent third exon and encoding a nonfunctional receptor, probably reflecting a defective trans-acting splicing factor. An atypical lariat region in the third intron may explain the presence of small amounts of this product in control patients.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
8/9. A case with 47,XXY,del(15)(q11;q13) karyotype associated with Prader-Willi phenotype.Herein we present the case of a 12-year-old boy who attended our clinic for obesity and hyperphagia. As a newborn he was noted to have diffuse muscular hypotonia and poor sucking response. At the age of 11 years, he was admitted to hospital for respiratory insufficiency. He had personality disorders characterized by temper tantrums and violent outbursts including self-mutilation. Physical evaluation revealed marked central obesity, he had small hands and feet, and also genital hypoplasia. Of the biochemical parameters, hyperglycemia and a low serum testosterone level must be emphasized. The patient fulfills the clinical criteria of typical prader-willi syndrome. Cytogenetic and fluorescence in situ hybridization analysis showed a karyotype 47,XXY, del(15)(q11;q13). To our knowledge this is the first report of the aforementioned genotype expressed as Prader-Willi phenotype in childhood.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
9/9. Characterization of a supernumerary small marker x chromosome in two females with similar phenotypes.We describe two female patients mosaic for a cell line with an extra marker x chromosome in addition to a normal 46,XX cell line. To our knowledge, these cases are the first reports of females who had a cell line with a supernumerary marker x chromosome in addition to a normal cell line. They also had strikingly similar manifestations, including small hands and feet, minor facial anomalies, obesity, and mental retardation. The dna content of the mar(X) chromosomes was investigated by fluorescent in situ hybridization using pericentromeric probes. The XIST gene, which is necessary for initiation of X-inactivation, was deleted from both marker chromosomes, suggesting that these chromosomes were not subject to inactivation. The short arm breakpoints of the mar(X)s were between the dna markers DXS423E on Xp11.21 and UBE1 on Xp11.23. In Patient 1, mar(X) contained the androgen receptor gene and the dna marker DXS1, both mapping to Xq11.2, whereas in Patient 2 the chromosome breakpoint was proximal to these markers. We suggest that the similar phenotypes of these patients may be due to the overexpression of genes in the common pericentromeric region of the x chromosome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |