C677T polymorphism of the 5,10-Methylenetetra-hydrofolate reductase [MTHFR] gene as a risk factor for neural tube defects among Egyptian families

Methylenetetrahydrofolate reductase [MTHFR] deficiency leads to impairment in folate metabolism and is implicated as a risk factor for neural tube defects [NTDs]. C677T MTHFR polymorphism is associated with NTDs, in some populations. Although the prevalence of this mutation has been reported from various ethnic populations, no data concerning Egyptian are available. C677T polymorphism was analyzed by PCR-RFLP. The frequencies of the C677T MTHFR polymorphism was determined in 35 case mothers, 19 case fathers and 9 children with NTDs compared with healthy 30 matched controls. In addition, allele and genotype frequencies were classified into different groups according to offspring NTD phenotype, consanguinity of the parents and number of affected offspring with NTD and or abortion. The prevalence of the polymorphic, homozygous [T/T] and heterozygous [C/T] C677T MTHFR genotypes were 6.3% and 38.1%, respectively, giving an allele frequency of 0.25. We observed increased frequency of heterozygotes of MTHFR in NTDs mothers versus the control although, C677T allele frequency was 0.28 in controls. Consanguinity rate was 45.7% among our families but it seems unlikely that it had an additional effect on the heterozygosity of the mutant genotype in this sample. In conclusion, neither homozygosity nor heterozygosity for the C677T polymorphism in the MTHFR gene constitute a genetic risk factor in the total NTDs but could be a risk of spina bifida aperta in this sample of Egyptian families. It is noteworthy to mention that this is the first report from Egypt evaluating the relationship between MTHFR677C>T and NTD

Hiperhomocist(e)inemia / Hyperhomocyst(e)inemia

A través de numerosos datos derivados de observaciones epidemiológicas y experimentales, se ha establecido que existe una correlación positiva entre la hiperhomocist(e)inemia (HH(e)) y las enfermedades vasculares. Los datos clínicos confirman que la homocisteína (Hcy) es un factor de riesgo independiente de afecciones arteriales oclusivas (coronaria, cerebrovascular y periféricovascular) así como también trombosis venosa periférica. Este aminoácido contiene un sulfhidrilo y se forma por la desmetilación de la metionina. Es normalmente catalizado a cistationina por la enzima cistationina ß-sintetasa (CBS), dependiente de fosfato de piridoxal. Homocisteína también es remetilada a metionina por las enzimas 5-metiltetrahidrofolato-Hcy metiltransferasa (metionina sintetasa), dependiente de vitamina B12 y betaína-Hcy metiltransferasa. Estados nutricionales tales como deficiencias en vitamina B12, vitamina B6 o folato y defectos genéticos de las enzimas CBS o 5,10-metilentetrahidrofolato reductasa, pueden contribuir al aumento de los niveles plasmáticos de Hcy. La patogénesis del daño vascular inducido por Hcy puede ser multifactorial: daño directo sobre el endotelio, aumento de la peroxidación de lipoproteínas de baja densidad, incremento de tromboxano A2 plaquetario o menor activación de la proteína C. En el presente trabajo, se describen los más recientes estudios acerca de la patogénesis de la HH(e) y las implicancias para una óptima terapia