The genetic relationship of abetalipoproteinemia and hypobetalipoproteinemia: a report of the occurence of both diseases within the same family.

A new case of abetalipoproteinemia (ABL) is reported after its recognition during an acquired hemorrhagic disthesis at parturition in a 37-year-old female. The new born infant of that delivery and 4 other first-degree relatives were subsequently studied and found to have hypobetalipoproteinemia (HBL). ABL and HBL, while sharing many clinical and biochemical similarities have, but rarely, been demonstrated within the same kindred and have, therefore, been regarded as different genetic mutations. Analysis of the data in the present and two other reported families indicates that ABL can result from the homozygous inheritance of the same gene which, when present in the heterozygous state, results in HBL't is concluded, therefore, that these cases of ABL have apparently been inherited via a different genetic mutation than most previously reported cases of ABL,and is likely the same gene involved in HBL. The clinical presentation of this form of ABL, that is, familial homozygous hypobetalipoproteinemia, is compared to that of the classical form of ABL.