Amyloid : the international journal of experimental and clinical investigation : the official journal of the International Society of Amyloidosis
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Serum transthyretin (TTR) levels are reduced in familial amyloidotic polyneuropathy (FAP). A single study of patients with senile systemic amyloidosis (SSA) in Sweden found that those individuals also had a significantly lower mean serum TTR concentration than age- and gender-matched controls. To determine if the same phenomenon prevailed in an ethnically more heterogeneous population, we compared the serum TTR levels, as determined by ELISA, in 45 documented SSA patients with congestive heart failure, 20 AL patients with congestive heart failure and population controls. ⋯ We also compared TTR concentrations in 12 African-Americans carrying the TTR V122I allele with those in 826 African-Americans who were homozygous wild type at the TTR locus. The TTR V122I carriers had significantly lower serum TTR concentrations than appropriate controls even though the majority of such individuals had not reached the age of clinical or anatomic risk, i.e. over 60. Thus, as in carriers of other TTR mutations the serum TTR level is lower than normal, despite having a much later appearance of clinical disease.