Senile cardiac amyloidosis associated with homozygosity for a transthyretin variant (ILE-122). Senile cardiac amyloidosis, also known as senile systemic amyloidosis, is a sporadic disease of late onset but with increasing incidence with age. Recently it has been shown in one case that amyloid deposits contained a transthyretin variant with an isoleucine for valine substitution at position 122. A second case with the transthyretin isoleucine 122 variant is reported here. This individual, who died with restrictive cardiomyopathy, was found to be homozygous for this transthyretin variant and his son heterozygous for the variant. A brother of the propositus was also homozygous for the variant but died of a cerebral vascular accident without being evaluated for amyloidosis. These studies show genetic transmission of the isoleucine-122 transthyretin variant associated with this form of cardiac amyloidosis. 