Malformaciones congénitas: Aspectos generales y genéticos

Abstract

Developmental defects may be due to congenital malformations, deformations or disruptions; 10% of malformations are caused by environmental factors, 25% by genetics factors and 65% are due to unknown multifactorial problems. There is a developmental period of greater susceptibility to teratogens, which corresponds to the stages when most organs and systems are being formed. Ingestions of teratogenics plants may result in congenital anomalies in animal foetuses. Pesticide such as DDT, water contamination with the Hg and the endocrine disrupters affect embryogenesis of different animal species. As factors that provoke malformations there are environmental agents, infections and some drugs. Physical agents such as increased temperature, hypoxic conditions and radiation, affect different organisms from fishes to human. Genetic of malformations have been difficult to establish, mainly because most of them are characterized by diverse phenotypic aspects, apparently not related and variable for the different affected organisms. On the other hand, studies realized indicate that frequently in the genetic determination of malformations several genes and their interactions with the environment are involved, although it has been possible to establish monogenic determination for a few cases. Here we contrast these two types of genetic determination, describing the genetic factors involved in the neural tube defects and the CHARGE syndrome, respectively.