[Hyperhomocysteinemia: associated obstetric diabetes and fetal malformations]

In its biological complexity, pregnancy represents a challenge both for the maternal organism and the fetal development and growth. During this period, some peculiar pathologies of pregnancy can occur which can involve or the fetus only i.e.: spontaneous pregnancy loss, intrauterine growth retardation, defects of neural tube, until the intrauterine fetal death; or pathologies occurring in the placenta and thus involving maternal organism and fetus too, such as pre-eclampsia. All these pathologies recognize many risk factors, among them the hyperhomocysteinemia. Hyperhomocysteinoemia can be caused by enzymatic defects or lack of some vitamins cofactors (vitamin B6, vitamin B12 and folic acid). The genetic defects which, as homozygous genotype, cause high plasma levels of homocysteine are already well known; they lead to an activity reduction of the enzymes responsible for their metabolism, for example: the deficiency of cystathionine beta-synthase; the deficiency of the methylcobalamine production; the deficit of the 5-10 methylenetethrahydrofolate reductase (MTHFR). However, even the heterozygous genotypes, which have a variable incidence from 1/70 to 1/200 and directly of 5-15% for the C677T mutation of the 5-10 MTHFR, can determine a mild hyperhomocysteinemia with a consequent cardiovascular risk. The close implications, widely demonstrated in the international literature, between hyperhomocysteinemia and the maternal-fetal diseases are described.