Late onset of symptoms in an atypical patient with the cblJ inborn error of vitamin B12 metabolism: diagnosis and novel mutation revealed by exome sequencing
Inborn errors of vitamin B12 (cobalamin) metabolism are characterized by decreased
production of active cobalamin cofactors and subsequent deficiencies in the activities of
methionine synthase and methylmalonyl-CoA mutase. With the recent discovery of the cblJ
defect in two patients with phenotypes mimicking the cblF defect, there are nine genes
known to be involved in cobalamin metabolism. The new defect is caused by mutations in
the ABCD4 gene, encoding an ABC transporter. At the moment, there is no clear distinction …
production of active cobalamin cofactors and subsequent deficiencies in the activities of
methionine synthase and methylmalonyl-CoA mutase. With the recent discovery of the cblJ
defect in two patients with phenotypes mimicking the cblF defect, there are nine genes
known to be involved in cobalamin metabolism. The new defect is caused by mutations in
the ABCD4 gene, encoding an ABC transporter. At the moment, there is no clear distinction …
