11/1301. Partial trisomy D: a diagnostic and cytogenetic dilemma.An 18-month-old proposita with psychomotor retardation and other congenital abnormalities is presented. Chromosomal analysis of both parents proved normal. However, the karyotype of the proposita contained 47 chromosomes in both lymphocytes and cultured fibroblasts. The marker chromosome proved to be a deleted No. 14 or 15. Comparison of the reported cases of partial trisomy D indicates that a definitive clinical syndrome is not apparent in either case.- - - - - - - - - - ranking = 1keywords = chromosome (Clic here for more details about this article) |
12/1301. Terminal deletion, del(1)(p36.3), detected through screening for terminal deletions in patients with unclassified malformation syndromes.We report on a 4 year-old girl with a 1p36.3-pter deletion. Clinical findings included minor anomalies of face and distal limbs, patent ductus arteriosus, the Ebstein heart anomaly, and brain atrophy with seizures. Conventional GTG-banded chromosome analysis revealed a normal (46,XX) result. Subsequent analysis by fluorescent in situ hybridization (FISH) using distal probes demonstrated a deletion of 1p36.6-pter. Molecular investigations with microsatellite markers showed hemizygosity at three loci at 1p36.3 with loss of the paternal allele. The deletion of 1p36.3 is difficult to identify by banding alone; indeed, our patient represents the third reported case with a del(1)(p36.3) that was detected only after more detailed analysis. In all three cases the deletion was detected through screening of patients with multiple congenital anomalies/mental retardation syndromes suggestive of autosomal chromosome aberrations for subtelomeric submicroscopic deletions by means of FISH or microsatellite marker analysis. On the basis of these observations we highly recommend that FISH with a subtelomeric 1p probe be routinely performed in patients with similar facial phenotype, severe mental retardation and seizures, and a heart malformation, particularly the ebstein anomaly.- - - - - - - - - - ranking = 1keywords = chromosome (Clic here for more details about this article) |
13/1301. Leri-Weill syndrome as part of a contiguous gene syndrome at Xp22.3.We report on a mother and her 5-year old son, both with a terminal deletion of the short arm of the x chromosome. By molecular genetic analysis the breakpoint was located distal to steroid sulfatase gene. The boy manifested, due to nullisomy of this region, short stature (SHOX), chondrodysplasia punctata (ARSE), and mental retardation (putative mental retardation gene MRX 49). Short stature is present in mother and son, but both also had bilateral Madelung deformity, a key finding in the Leri-Weill syndrome.We discuss the phenotype in relationship to hitherto published cases with chromosomal aberrations and contiguous gene syndromes of Xp22.3.- - - - - - - - - - ranking = 0.5keywords = chromosome (Clic here for more details about this article) |
14/1301. Normal expression of the fanconi anemia proteins FAA and FAC and sensitivity to mitomycin C in two patients with Seckel syndrome.Seckel syndrome is a rare autosomal recessive disorder. The classical presentation includes pre- and postnatal growth deficiency, mental retardation, and characteristic facial appearance. There have been several reports of associated hematological abnormalities and chromosomal breakage, findings suggestive of fanconi anemia (FA). We tested for these findings in two Arabic patients with this syndrome. We compared the growth profile of lymphoblastoid cells from our patients and their parents with the FA group A cell line HSC72 in the presence and absence of mitomycin C (MMC). By Western analysis, we also determined the expression of FAA and FAC, two FA disease gene products that together account for approximately 80% of FA. Unlike HSC72 cells, cells from the patients were resistant to MMC, and both FAA and FAC proteins were expressed at similar levels in all cell lines. There is an increasing recognition of clinical variability and perhaps genetic heterogeneity in Seckel syndrome. Our results demonstrate that cross-link sensitivity comparable to FA is not a uniform finding in patients with Seckel syndrome.- - - - - - - - - - ranking = 0.25972823799228keywords = breakage (Clic here for more details about this article) |
15/1301. Parental origin of the isochromosome 12p in Pallister-Killian syndrome: molecular analysis of one patient and review of the reported cases.Pallister-Killian syndrome (PKS) is characterized by multiple congenital anomalies including pigmentary skin changes, mental retardation, and the mosaic presence of a tissue-limited isochromosome 12p [i(12p)]. Mechanism(s) of formation and parental origin of the isochromosome are not well understood. In this study, microsatellite dna markers of chromosome 12p were used to identify the parental origin of the extra chromosome in an 8-year-old previously reported patient with PKS. The i(12p) was found to be maternally inherited. Reported cases of PKS where the parental origin of the i(12p) was determined were also reviewed. In all the cases, with one exception, the errors were found to be maternal in origin. Premeiotic mitotic error may be the most likely mechanism for i(12p) formation in this syndrome.- - - - - - - - - - ranking = 4keywords = chromosome (Clic here for more details about this article) |
16/1301. Periventricular brain heterotopias in a child with adrenocortical insufficiency, achalasia, alacrima, and neurologic abnormalities (Allgrove syndrome).We describe a previously unreported finding of periventricular heterotopias in a brain magnetic resonance imaging (MRI) study, in a girl with adrenocortical insufficiency, alacrima, achalasia, and neurologic deterioration (Allgrove syndrome). This finding could indicate that the underlying mechanism in this syndrome can be traced to the first half of fetal life and also might cause abnormal neuronal migration. This disorder recently has been linked to chromosome 12q13. There could be several explanations for the clinical heterogeneity in this syndrome: a contiguous gene syndrome involving multiple genes, including one whose deletion causes heterotopias, or a deficiency of a gene for a neurotrophic factor active during pre- and postnatal life and responsible for both migration and survival of neurons could be the cause. The identification of the responsible gene(s) will lead to further understanding of this multisystem disorder.- - - - - - - - - - ranking = 0.5keywords = chromosome (Clic here for more details about this article) |
17/1301. Wolf's syndrome in twins -- translocation in the mother.A case of MZ twins, both affected by Wolf's syndrome, is described. Their mother, of subnormal look and low intellectual level is translocated. The children, born with a weight and size much below the average, show a very special morphotype; a hook-nose, an an abnormal conformation of the back edge of the nostrils (a protrusion in the shape of a horn overhanging the filtrum), hypertelorism, microcephaly. Great asynchronism in the maturation of the bones and a somatoschisis of the body of the cervical vertebrae are noted. Deletion of the short arm chromosome 4 is juxtacentromeric. The study of blood and tissue groups corroborates monozygosity. Dermatoglyphs are little abnormal and identical in the two children. The mother's family is phenotypically normal. At 19 months of age, measuring is still below 4, psychomotor progress is extremely weak, and convulsions are frequent.- - - - - - - - - - ranking = 0.5keywords = chromosome (Clic here for more details about this article) |
18/1301. campomelic dysplasia translocation breakpoints are scattered over 1 Mb proximal to SOX9: evidence for an extended control region.campomelic dysplasia (CD), a skeletal malformation syndrome with or without XY sex reversal, is usually caused by mutations within the SOX9 gene on distal 17q. Several CD translocation and inversion cases have been described with breakpoints outside the coding region, mapping to locations >130 kb proximal to SOX9. Such cases are generally less severely affected than cases with SOX9 coding-region mutations, as is borne out by three new translocation cases that we present. We have cloned the region extending 1.2 Mb upstream of the SOX9 gene in overlapping bacterial-artificial-chromosome and P1-artificial-chromosome clones and have established a restriction map with rare-cutter enzymes. With sequence-tagged-site-content mapping in somatic-cell hybrids, as well as with FISH, we have precisely mapped the breakpoints of the three new and of three previously described CD cases. The six CD breakpoints map to an interval that is 140-950 kb proximal to the SOX9 gene. With exon trapping, we could isolate five potential exons from the YAC 946E12 that spans the region, four of which could be placed in the contig in the vicinity of the breakpoints. They show the same transcriptional orientation, but only two have an open reading frame (ORF). We failed to detect expression of these fragments in several human and mouse cDNA libraries, as well as on northern blots. Genomic sequence totaling 1,063 kb from the SOX9 5'-flanking region was determined and was analyzed by the gene-prediction program GENSCAN and by a search of dbEST and other databases. No genes or transcripts could be identified. Together, these data suggest that the chromosomal rearrangements most likely remove one or more cis-regulatory elements from an extended SOX9 control region.- - - - - - - - - - ranking = 1keywords = chromosome (Clic here for more details about this article) |
19/1301. Char syndrome, an inherited disorder with patent ductus arteriosus, maps to chromosome 6p12-p21.BACKGROUND: Patent ductus arteriosus (PDA) is a relatively common form of congenital heart disease. Although polygenic inheritance has been implicated, no specific gene defects causing PDA have been identified to date. Thus, a positional cloning strategy was undertaken to determine the gene responsible for the Char syndrome, an autosomal dominant disorder characterized by PDA, facial dysmorphism, and hand anomalies. methods AND RESULTS: A genome scan was performed with 46 members of 2 unrelated families in which the disease was fully penetrant but the phenotype differed. Significant linkage was achieved with several polymorphic dna markers mapping to chromosome 6p12-p21 (maximal 2-point lod score of 8.39 with D6S1638 at theta=0.00). Haplotype analysis identified recombinant events that defined the Char syndrome locus with high probability to a 3. 1-cM region between D6S459/D6S1632/D6S1541 and D6S1024. CONCLUSIONS: A familial syndrome in which PDA is a common feature was mapped to a narrow region of chromosome 6p12-p21. Additional analysis with other families and polymorphic markers as well as evaluation of potential candidate genes should lead to the identification of the Char syndrome gene, which will provide insights into cardiogenesis as well as limb and craniofacial development.- - - - - - - - - - ranking = 3keywords = chromosome (Clic here for more details about this article) |
20/1301. The smith-magenis syndrome: a new case with infant spasms.The smith-magenis syndrome (SMS) is characterized by congenital anomalies, mental retardation and the interstitial deletion of the 17p. 11.2 chromosome. The subjects affected by this syndrome show cranio-facial dysmorphias, brachycephalia, skeletal, ocular, cardiac, genitourinary and otolaryngological anomalies. The central nervous system is affected and this may be shown by psychomotor retardation, intellective deficit, electroencephalographic alterations (reduced/missing REM phase); the neuroradiological tests detect megacisterna magna, cerebellar hypoplasia, cortical dysplasia, ventricular asymmetry. Behavioural troubles are frequent and, among them, self-aggressive conducts (tearing out the nails). The syndrome is associated with the interstitial deletion of the 17p. 11.2 chromosome. The diagnosis can be made in the pre-natal period and a mosaic situation is possible. Even though the cases of SMS reported in the literature allow defining a characteristic phenotype, studies have been carried out to quantify the deletion of the chromosome 17 in order to identify the chromosomic tract which is responsible for the phenotypical induction. The deletion can either appear de novo or come from one of the parents. In addition, these subjects can show peripheral neuropathy, missing or reduced deep tendon reflexes and (rarely) epileptic crises. However, by reviewing the literature, no descriptions of patients affected by infant spasms are pointed out. This report refers to a new case of smith-magenis syndrome in a nine-month-old girl with spasms in extension.- - - - - - - - - - ranking = 1.5keywords = chromosome (Clic here for more details about this article) |
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