Twelve members of family pedigree of hypo-β-lipoproteinemia were analyzed for lipoprotein compositions, apo B levels by EIA, its isoforms by SDS gel electrophoresis.
Judging from LDL-chol & apo B levels, a 75-year-old proband father who died of unknown fever, thrombopenia, and anemia, and his wife were heterozygous. The father had ataxic movement of hands and gait disturbance in the late life. Three out of 4 alive siblings had deficiency of LDL-chol (<6mg/dl) and LDL-apo B (<2mg/dl). Electrophoresis revealed deletion of apo B-100, but exhibited apo B-48 band in serum obtained after fatty meal in these 3 siblings, indicating homozygous inheritance. Clinically, acanthocytic RBC, fatty liver and low levels of serum vitamin A & D were noted. The other heterozygous sibling had 26mg/dl LDL-chol and 5mg/dl apo-B levels. Seven persons with the 3rd generation showed all low levels of chol (85-140mg/dl), LDL-chol (40-63mg/dl) and apo B (10-20mg/dl). They also showed mild acanthocytosis and a decrease of fatsoluble vitamines.
The present cases are similar to the preveously reported 2 cases with normotriglyceridemic abetalipoproteinemia, but are the first demonstration of selective apo B-100 deletion in homozygous hypo-β-lipoproteanemia.
