Trifunctional protein deficiency: three families with significant maternal hepatic dysfunction in pregnancy not associated with E474Q mutation.

We report five families with trifunctional protein deficiency in which, during pregnancy, three mothers experienced significant hepatic disease when carrying an affected fetus. Diagnoses were based on increased levels of long-chain hydroxyacylcarnitines and deficiencies of 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and 3-ketoacyl-CoA thiolase activity in fibroblasts. All affected infants lacked the common E474Q mutation associated with isolated LCHAD deficiency. This mutation is thought to be a predisposing factor for maternal hepatic disease in pregnancy. Our findings suggest that other defects in this enzyme complex might be responsible for maternal hepatic complications in pregnancy.