Familial hypobetalipoproteinemia: a novel mutation in APOB gene and review of the literature

Familial hypobetalipoproteinemia is an autosomal dominantly inherited disorder of lipid metabolism characterized by a <5th percentile plasma levels of low-density lipoprotein cholesterol or total apolipoprotein B, caused by mutations in the APOB gene. Patients with heterozygous APOB-related familial hypobetalipoproteinemia are usually asymptomatic or manifest with mild liver dysfunction or hepatic steatosis. A 14-year-old Korean boy was referred to our clinic because of low low-density lipoprotein cholesterol and elevated aminotransferase levels. He did not complain specific symptoms of hypobetalipoproteinemia, but his laboratory and radiologic tests showed low low-density lipoprotein cholesterol, low apolipoprotein B, high aminotransferases, severe fatty liver, and hepatosplenomegaly. A multigene panel test identified a heterozygous mutation for p.Lys3846Ter (c.11536A>T) in the APOB gene, which has not been reported in previous studies and was not detected in his parents with normal lipid profiles. Limiting intake of saturated fat, increased physical activity, and vitamin E supplementation were performed. Subsequent laboratory tests revealed normalized aminotransferase levels.