Fatty liver in a case with heterozygous familial hypobetalipoproteinemia.

We herein present a case of fatty liver in a patient with heterozygous familial hypobetalipoproteinemia. A 34-yr-old male presented with abnormally elevated levels of transaminases and a fatty liver. He was asymptomatic, and the physical examination showed nothing remarkable. The serum total cholesterol, triglyceride, LDL-cholesterol, and apolipoprotein B levels all ranged from low normal to one-half normal. His other laboratory data were all in the normal range. The patient's body mass index measured was 25.7 kg/m2, and he did not demonstrate obesity. He had no history of alcohol consumption. It was thus thought that the fatty liver in this case might be associated with heterozygous hypobetalipoproteinemia. Heterozygous hypobetalipoproteinemia with a bright liver by ultrasound was also found in several of the patient's family members. Based on these rare findings, heterozygous hypobetalipoproteinemia should thus be considered as a possible cause in patients presenting with an unexplained fatty liver.