Pseudohomozygous and Pseudoheterozygous Type II Hyperlipoproteinemia

Abstract

\s=b\A 4-year-old boy had typical features of homozygous type II hyperlipoproteinemia with planar xanthomas, a plasma cholesterol level greater than 600 mg/dl, and an estimated \g=b\-lipoprotein cholesterol concentration greater than 500 mg/dl. Both he and his sister, who had the biochemical features of the heterozygous state, responded unusually well to a diet low in saturated fat and cholesterol content. These features, combined with

Pseudohomozygous type II hyperlipoproteinemia

“…Accordingly, at this time we agree with previous authors (Morganroth et al, 1974;Mishkel, 1976) that these cases appear to represent a new clinical hypercholesterolemic syndrome with manifestations resembling homozygous familial hypercholesterolemia.…”

“…The additional case with an older sister who had the biochemical features of the heterozygous state was reported by Mishkel (1976), but LDL receptor activity of the cultured fibroblasts was not examined. This evidence for familial occurrence of this disorder suggests that it is not due to an autosomal dominant gene, but due to an autosomal recessive gene.…”

Pseudohomozygous Type II Hyperlipoproteinemia

“…but their parents had no lipid abnormalities. Mishkel [6] reported a similar case and also a case with hyperlipoproteinemia without xanthoma. This prompted him to use the term of 'pseudohomozygous et heterozy gous type 11 hyperlipoproteinemia'.…”

“…[1] stated that the xanthoma was pla-nar. Mishkel [6], however, noted that it was a streak-like xanthoma in neonatal clefts. Streak-like xanthoma in the intergluteal area, antecubital fossae or popliteal fossae have also been observed in the first case of Morganroth et al [ 1], in MishkcTscase [6], in the second case of Mabuchi ct al.…”

Sitosterolemia Presenting as Pseudohomozygous Familial Hypercholesterolemia

“…[7][8][9] Cerebrotendinous xanthomatosis, which can also present with xanthomas early in life, was ruled out by the profound hypercholesterolemia and the sterol analysis showing diagnostic elevation of plant sterol levels.…”