The C677T polymorphism of the methylenetetrahydrofolate reductase gene in Mexican mestizo neural-tube defect parents, control mestizo and native populations.

The C677T mutation of the methylenetetrahydrofolate reductase (MTHFR) gene, associated with the thermolabile form of the enzyme, has reportedly been found to be increased in neural-tube defects (NTD), though this association is still unclear. A group of 107 mestizo parents of NTD children and five control populations: 101 mestizo (M), 50 Huichol (H), 38 Tarahumara (T), 21 Purepecha (P) and 20 Caucasian (C) individuals were typed for the MTHFR C677T variant by the PCR/RFLP (HinfI) method. Genotype frequencies were in agreement with the Hardy-Weinberg expectations in all six populations. Allele frequency (%) of the C677T variant was 45 in NTD, 44 in M, 56 in H, 36 in T, 57 in P, 35 in C. Pairwise inter-population comparisons of allele frequency disclosed a very similar distribution between NTD and M groups (exact test, P=0.92). Among controls, differences between M and individual native groups were NS (0.06

Clinical, morphological and biochemical features in the familial articular hypermobility syndrome (FAHS): a family study.

A female with clinical features of familial articular hypermobility syndrome (FAHS) and her family were studied. The subject showed generalized hypermobility, except for a painful shoulder which presented functional limitation with a diagnosis of painful shoulder syndrome. Biochemical studies demonstrated that collagen and glycosaminoglycans (GAGs) contents from skin biopsies of the subject and her family were almost normal. Nevertheless, the densitometric analysis of electrophoretic patterns showed differences in the relative proportions of their collagenous components. They were characterized by changes in type I and III collagens and the presence of type V collagen, in the subject, her father and brother. Also, they presented changes in the types of GAGs, when compared with those of normal skin. Morphological studies revealed a general disorganization of dermal components, a loose collagen network characterized by thick bundles. Also, besides cellular elements, the presence of an abundant darkly staining material was observed. Biochemical and morphological findings permit us to suggest a connective tissue defect, initially described in the FAHS, otherwise known as Ehlers Danlos syndrome (EDS) type XI.