Fetal dilated cardiomyopathy: an unsuspected presentation of methylmalonic aciduria and hyperhomocystinuria, cblC type

Abstract

To report the prenatal presentation with dilated cardiomyopathy of methylmalonic aciduria and homocystinuria, cblC type [cobalamin C (cblC) deficiency] (MIM 277400). We describe a boy with cblC deficiency who presented prenatally with fetal ultrasound findings of dilated cardiomyopathy and growth restriction. Dilated cardiomyopathy and growth retardation were detected in the third trimester of an initially uncomplicated pregnancy. Investigations were negative for chromosomal and other known causes. Growth restriction persisted but fetal heart function improved. Postnatal biochemical evaluation revealed combined methylmalonic acidemia and homocystinemia. Molecular investigations confirmed cblC deficiency. Initiation of treatment was followed by rapid clinical improvement. Prenatal dilated cardiomyopathy can be the presenting sign of cblC deficiency. Inborn errors of metabolism should be considered in the investigation of prenatally diagnosed dilated cardiomyopathy in view of the possible impact on treatment and future reproductive options, in some of these conditions.