Association between selected folate pathway polymorphisms and nonsyndromic limb reduction defects: a case-parental analysis.

Inadequate folate status resulting from either genetic variation or nutritional deficiencies has been associated with an increased risk of congenital malformations including orofacial clefting, limb, cardiac and neural tube defects. Few epidemiological studies have examined the association between limb reduction defects (LRDs) and folate-related genetic polymorphisms other than MTHFR 677C→T. We conducted a case-parental analysis of 148 families who participated in the National Birth Defects Prevention Study to examine the association between nonsyndromic transverse and longitudinal LRDs with five single nucleotide polymorphisms (SNPs) in genes encoding enzymes in folate and methionine pathways.

A novel mutation in FGFR3 causes camptodactyly, tall stature, and hearing loss (CATSHL) syndrome.

Activating mutations of FGFR3, a negative regulator of bone growth, are well known to cause a variety of short-limbed bone dysplasias and craniosynostosis syndromes. We mapped the locus causing a novel disorder characterized by camptodactyly, tall stature, scoliosis, and hearing loss (CATSHL syndrome) to chromosome 4p. Because this syndrome recapitulated the phenotype of the Fgfr3 knockout mouse, we screened FGFR3 and subsequently identified a heterozygous missense mutation that is predicted to cause a p.

Identification of nine novel DHCR7 missense mutations in patients with Smith-Lemli-Opitz syndrome (SLOS).

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive, multiple congenital anomaly syndrome caused by deficiency of 7-dehydrocholesterol reductase (DHCR7), which catalyzes the last step of endogenous cholesterol synthesis. Surveys of SLOS patients have identified more than one hundred point mutations of the DHCR7 gene, most of which are missense mutations. Here, we report the identification of nine novel missense mutations of the DHCR7 gene.

Residual cholesterol synthesis and simvastatin induction of cholesterol synthesis in Smith-Lemli-Opitz syndrome fibroblasts.

Smith-Lemli-Opitz syndrome (RSH/SLOS) is an autosomal recessive, malformation syndrome caused by mutations in the 3beta-hydroxysterol delta7-reductase gene (DHCR7). DHCR7 catalyzes the reduction of 7-dehydrocholesterol (7DHC) to cholesterol. We report the mutation analysis and determination of residual cholesterol synthesis in 47 SLOS patients, and the effects of treatment of SLOS skin fibroblasts with simvastatin.

Lathosterolosis: an inborn error of human and murine cholesterol synthesis due to lathosterol 5-desaturase deficiency.

Lathosterol 5-desaturase catalyzes the conversion of lathosterol to 7-dehydrocholesterol in the next to last step of cholesterol synthesis. Inborn errors of cholesterol synthesis underlie a group of human malformation syndromes including Smith-Lemli-Opitz syndrome, desmosterolosis, CHILD syndrome, CDPX2 and lathosterolosis. We disrupted the lathosterol 5-desaturase gene (Sc5d ) in order to further our understanding of the pathophysiological processes underlying these disorders and to gain insight into the corresponding human disorder.

A defective response to Hedgehog signaling in disorders of cholesterol biosynthesis.

Smith-Lemli-Opitz syndrome (SLOS), desmosterolosis and lathosterolosis are human syndromes caused by defects in the final stages of cholesterol biosynthesis. Many of the developmental malformations in these syndromes occur in tissues and structures whose embryonic patterning depends on signaling by the Hedgehog (Hh) family of secreted proteins. Here we report that response to the Hh signal is compromised in mutant cells from mouse models of SLOS and lathosterolosis and in normal cells pharmacologically depleted of sterols.

Mutations in genes encoding fast-twitch contractile proteins cause distal arthrogryposis syndromes.

The distal arthrogryposes (DAs) are a group of disorders characterized by multiple congenital contractures of the limbs. We previously mapped a locus for DA type 2B (DA2B), the most common of the DAs, to chromosome 11. We now report that DA2B is caused by mutations in TNNI2 that are predicted to disrupt the carboxy-terminal domain of an isoform of troponin I (TnI) specific to the troponin-tropomyosin (Tc-Tm) complex of fast-twitch myofibers.