VITREOUS AMYLOIDOSIS ASSOCIATED WITH HOMOZYGOSITY FOR THE TRANSTHYRETIN METHIONINE-30 GENE

Familial amyloidotic polyneuropathy is an autosomal dominant inherited disorder. Biochemical studies have revealed that the amyloid protein in familial amyloidotic polyneuropathy of Japanese, Swedish, and Portuguese origin mainly consists of a variant transthyretin with one amino acid substitution of methionine for valine at position 30, termed TTR met-30. In five Swedish patients with familial amyloidotic polyneuropathy we diagnosed homozygosity for the TTR met-30 gene using restriction fragment length polymorphism analysis. The homozygous individuals did not show more severe systemic symptoms or earlier onset than heterozygotes for the TTR met30 gene. The only clinical difference was the presence of vitreous opacities in all homozygous patients. © 1990, American Medical Association. All rights reserved.