Publications by authors named "Stephen Dlouhy"

Wiedemann-Steiner syndrome is a genetic condition associated with dysmorphic facies, hypertrichosis, short stature, developmental delay, and intellectual disability. Congenital malformations of the cerebral, cardiac, renal, and optic structures have also been reported. Because the majority of reported individuals with this condition have been under age 20, the long-term prognosis is not well defined.

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Mutations in the STE20-related kinase adaptor α ( STRADA) gene have been reported to cause an autosomal recessive neurodevelopmental disorder characterized by infantile-onset epilepsy, developmental delay, and craniofacial dysmorphisms. To date, there have been 17 reported individuals diagnosed with STRADA mutations, 16 of which are from a single Old Order Mennonite cohort and share a deletion of exons 9-13. The remaining individual is of consanguineous Indian descent and has a homozygous single-base pair duplication.

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In the field of dysmorphology, achondroplasia is a well-known disorder. Sinus pericranii (SP), however, is not. The latter condition is a rare vascular malformation characterized by abnormal connections between the intracranial and the extracranial venous drainage pathways.

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Cystic fibrosis (CF) is an autosomal recessive disorder characterized by the accumulation of sticky and heavy mucus that can damage several organs. CF shows variable expressivity in affected individuals, but it typically causes respiratory and digestive complications as well as congenital bilateral absence of the vas deferens in males. Individuals with classic CF usually have variants that produce a defective protein from both alleles of the CFTR gene.

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Purpose: The purpose of this study is to evaluate the incidence of maternal cell contamination (MCC) in the first few milliliters of amniotic fluid withdrawn during amniocentesis.

Methods: A prospective observational study was performed. The initial 2-3 ml of amniotic fluid withdrawn during amniocentesis was divided into direct analysis (uncultured) and cultured samples.

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Myotonic dystrophy types 1 (DM1) and 2 (DM2) are autosomal dominant, microsatellite repeat expansion disorders that affect muscle function. Myotonic dystrophy type 1 is caused by CTG repeat expansion in the 3' UTR region of the DMPK gene. Patients with DM2 have expansion of CCTG repeats in intron 1 of the CNBP gene.

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Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is an autosomal recessive disorder that leads to a defect in fatty acid oxidation. ACADM is the only candidate gene causing MCAD deficiency. A single nucleotide change, c.

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Myotonic dystrophy type 1 (DM1) is an autosomal dominant neuromuscular disease caused by expansion of a CTG trinucleotide repeat in the DMPK gene. Methodology for genetic testing of DM1 is currently not optimal, in particular for the early-onset patients in pediatric populations where large expanded (CTG)n alleles are usually common. Individuals who are homozygous for a normal allele and individuals who are heterozygous for one normal and one large expanded allele are indistinguishable by conventional PCR, as both generate a single product of the normal allele.

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First identified in 1997, cell-free fetal DNA (cffDNA) has just recently been used to detect fetal aneuploidy of chromosomes 13, 18, and 21, showing its potential to revolutionize prenatal genetic testing as a non-invasive screening tool. Although this technological advancement is exciting and has certain medical applications, it has been unclear how it will be implemented in a clinical setting. Genetic counselors will likely be instrumental in answering that question, but to date, there is no published research regarding prenatal counselors' implementation of and experiences with cffDNA testing.

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Mutations in Tau cause the inherited neurodegenerative disease, frontotemporal dementia and Parkinsonism linked to chromosome 17 (FTDP-17). Known coding region mutations cluster in the microtubule-binding region, where they alter the ability of tau to promote microtubule assembly. Depending on the tau isoforms, this region consists of three or four imperfect repeats of 31 or 32 amino acids, each of which contains a characteristic and invariant PGGG motif.

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Background: The genes for salivary androgen-binding protein (ABP) subunits have been evolving rapidly in ancestors of the house mouse Mus musculus, as evidenced both by recent and extensive gene duplication and by high ratios of nonsynonymous to synonymous nucleotide substitution rates. This makes ABP an appropriate model system with which to investigate how recent adaptive evolution of paralogous genes results in functional innovation (neofunctionalization).

Results: It was our goal to find evidence for the expression of as many of the Abp paralogues in the mouse genome as possible.

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Most cerebellar granule neurons in weaver mice undergo premature apoptosis during the first 3 postnatal weeks, subsequently leading to severe ataxia. The death of these granule neurons appears to result from a point mutation in the GIRK2 gene, which encodes a G protein-activated, inwardly rectifying K+ channel protein. Although the genetic defect was identified, the molecular mechanism by which the mutant K+ channel selectively attacks granule neurons in weaver mice is unclear.

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Huntington's disease (HD) is an autosomal dominant neurodegenerative disease caused by a triplet (CAG) expansion mutation. The length of the triplet repeat is the most important factor in determining age of onset of HD, although substantial variability remains after controlling for repeat length. The Venezuelan HD kindreds encompass 18,149 individuals spanning 10 generations, 15,409 of whom are living.

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Mouse salivary androgen-binding protein (ABP) is a pair of dimers, composed of an alpha subunit disulfide bridged to either a beta or a gamma subunit. It has been proposed that each subunit is encoded by a distinct gene: Abpa, Abpb, and Abpg for the alpha, beta, and gamma subunits, respectively. We report here the structures and sequences of the genes that encode these three subunits.

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Pelizaeus-Merzbacher disease (PMD) is a dysmyelinating disorder of the central nervous system typically caused by duplications or missense mutations of the proteolipid protein (PLP) gene. Most investigators have found that peripheral nerve function and structure is normal in PMD patients. We have found that null mutations of the PLP gene cause demyelinating peripheral neuropathy, whereas duplications and a proline 14 to leucine mutation do not affect nerve function.

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