Cohen syndrome is an uncommon autosomal recessive disorder whose diagnosis is based on the clinical picture of nonprogressive psychomotor retardation and microcephaly, characteristic facial features, retinal dystrophy, and intermittent neutropenia. We have refined the critical region on chromosome 8q22 by haplotype analysis, and we report the characterization of a novel gene, COH1, that is mutated in patients with Cohen syndrome. The longest transcript (14,093 bp) is widely expressed and is transcribed from 62 exons that span a genomic region of approximately 864 kb.
View Article and Find Full Text PDFHereditary non-polyposis colorectal cancer is characterized by mutations in one of the DNA mismatch repair genes, primarily MLH1, MSH2, or MSH6. We report here the identification of a genomic deletion of approximately 11.4 kb encompassing the first two exons of the MSH2 gene in two generations of an Ohio family.
View Article and Find Full Text PDFThe identification of germline mutations in families with HNPCC is hampered by genetic heterogeneity and clinical variability. In previous studies, MSH2 and MLH1 mutations were found in approximately two-thirds of the Amsterdam-criteria-positive families and in much lower percentages of the Amsterdam-criteria-negative families. Therefore, a considerable proportion of HNPCC seems not to be accounted for by the major mismatch repair (MMR) genes.
View Article and Find Full Text PDFBackground: In stressful conditions, increasing blood glucose concentrations are closely related to an increase in catecholamines and cortisol release. Clonidine, a centrally acting alpha(2)-adrenoceptor agonist, has neuroendocrine effects, including inhibition of sympathoadrenal activity. We therefore evaluated the effect of clonidine on blood glucose control and insulin requirements during ophthalmic surgery when given as premedication in type 2 diabetic patients.
View Article and Find Full Text PDFWe previously obtained gene expression profiles of 8 matched papillary thyroid carcinoma (PTC) and normal tissues using DNA microarrays. To identify novel tumor suppressor genes involved in thyroid carcinogenesis, we here analyze genes showing lower expression in PTC tumors than in normal thyroid tissues. A search for loss of heterozygosity (LOH) in 49 regions that harbor consistently down-regulated genes revealed LOH in only 4 regions and in just a very small number of tumors.
View Article and Find Full Text PDFThe amnionless gene, Amn, on mouse chromosome 12 encodes a type I transmembrane protein that is expressed in the extraembryonic visceral layer during gastrulation. Mice homozygous with respect to the amn mutation generated by a transgene insertion have no amnion. The embryos are severely compromised, surviving to the tenth day of gestation but seem to lack the mesodermal layers that normally produce the trunk.
View Article and Find Full Text PDFHereditary nonpolyposis colorectal cancer (HNPCC) is caused by mutations in the mismatch-repair genes. We report here the identification and characterization of a founder mutation in MSH2 in the Ashkenazi Jewish population. We identified a nucleotide substitution, MSH2*1906G-->C, which results in a substitution of proline for alanine at codon 636 in the MSH2 protein.
View Article and Find Full Text PDFTP53 does not fully comply with the Knudson model [Knudson, A. G., Jr.
View Article and Find Full Text PDFMutations that alter normal splice patterns and genomic rearrangements are common causes of hereditary diseases including hereditary nonpolyposis colorectal cancer. However, abnormal transcripts can be difficult to detect and interpret because splicing patterns are often heterogeneous even in normal cells. Standard techniques including sequencing and Southern hybridization fail to detect some genomic rearrangements.
View Article and Find Full Text PDFPTEN on 10q23.3 encodes a dual-specificity phosphatase that negatively regulates the phosphoinositol-3-kinase/Akt pathway and mediates cell-cycle arrest and apoptosis. Germline PTEN mutations cause Cowden syndrome and a range of several different hamartoma-tumor syndromes.
View Article and Find Full Text PDFX-linked CSNB patients may exhibit myopia, nystagmus, strabismus and ERG abnormalities of the Schubert-Bornschein type. We recently identified the retina-specific L-type calcium channel alpha1 subunit gene CACNA1F localised to the Xp11.23 region, which is mutated in families showing the incomplete type (CSNB2).
View Article and Find Full Text PDFWe report the case of a pregnant patient who developed severe pulmonary edema secondary to beta-adrenergic agonist tocolytic therapy (salbutamol) and was successfully treated with mask-delivered continuous positive airway pressure ventilation.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2001
Papillary thyroid carcinoma (PTC) is clinically heterogeneous. Apart from an association with ionizing radiation, the etiology and molecular biology of PTC is poorly understood. We used oligo-based DNA arrays to study the expression profiles of eight matched pairs of normal thyroid and PTC tissues.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2001
Steroid hormones are central regulators of a variety of biological processes. According to the free hormone hypothesis, steroids enter target cells by passive diffusion. However, recently we demonstrated that 25(OH) vitamin D(3) complexed to its plasma carrier, the vitamin D-binding protein, enters renal proximal tubules by receptor-mediated endocytosis.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2001
The molecular basis of human leukemia is heterogeneous. Cytogenetic findings are increasingly associated with molecular abnormalities, some of which are being understood at the functional level. Specific therapies can be developed based on such knowledge.
View Article and Find Full Text PDFHypermethylation of the MLH1 promoter underlies most sporadic colorectal cancers with microsatellite instability (MSI). To investigate the role of hypermethylation in the normal colonic mucosa as a possible precursor lesion, we studied 700 bp upstream of MLH1 covering 51 CpG sites. We found partially methylated alleles in 15 of 34 (44%) patients <60 years of age and 20 of 24 (83%) patients > or =80 years of age (P = 0.
View Article and Find Full Text PDFThe retinoblastoma protein-interacting zinc finger gene RIZ (PRDM2) is a member, by sequence homology, of a nuclear protein-methyltransferase (MTase) superfamily involved in chromatin-mediated gene expression. The gene produces two protein products, RIZ1 that contains a conserved MTase domain and RIZ2 that lacks the domain. RIZ1 gene expression is frequently silenced in human cancers, and the gene is also a common target of frameshift mutation in microsatellite-unstable cancers.
View Article and Find Full Text PDFUsher syndrome type 3 (USH3) is an autosomal recessive disorder characterized by progressive hearing loss, severe retinal degeneration, and variably present vestibular dysfunction, assigned to 3q21-q25. Here, we report on the positional cloning of the USH3 gene. By haplotype and linkage-disequilibrium analyses in Finnish carriers of a putative founder mutation, the critical region was narrowed to 250 kb, of which we sequenced, assembled, and annotated 207 kb.
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