Genetic disorders of vitamin B12metabolism: eight complementation groups – eight genes

Abstract

Vitamin B12(cobalamin, Cbl) is an essential nutrient in human metabolism. Genetic diseases of vitamin B12utilisation constitute an important fraction of inherited newborn disease. Functionally, B12is the cofactor for methionine synthase and methylmalonyl CoA mutase. To function as a cofactor, B12must be metabolised through a complex pathway that modifies its structure and takes it through subcellular compartments of the cell. Through the study of inherited disorders of vitamin B12utilisation, the genes for eight complementation groups have been identified, leading to the determination of the general structure of vitamin B12processing and providing methods for carrier testing, prenatal diagnosis and approaches to treatment.