Mutações no gene da metilenotetrahidrofolato redutase e síndrome de Down

Abstract

Down syndrome (DS) is a complex genetic and metabolic disorder attributed to the presence of three copies of chromosome 21. The extra chromosome derives from the mother in 93% of cases and is due to abnormal chromosome segregation during meiosis (nondisjunction). Except for advanced age at conception, maternal risk factors for meiotic nondisjunction are not well established. A recent preliminary study suggested that abnormal folate metabolism and the 677 (C-->T) mutation in the methylene-tetrahydrofolate reduc…