Familial amyloidotic polyneuropathy type 1 in Brazil is associated with the transthyretin Val30Met variant

Familial amyloidotic polyneuropathy type I (FAP1) is an inherited systemic amyloidosis that is secondary to the deposition of transthyretin (TTR) variants in peripheral nerves and in certain visceral organs. More than 50 distinct mutations have already been described in the TTR gene. Yet, the most common mutation found worldwide is a substitution of valine for methionine in position 30 (Val30Met). Currently, the variants of TTR in Brazilian FAP1 patients remain largely unknown and the aim of this study was to analyze the frequency of the TTR Val30Met mutation in such Brazilian subjects. Methods: Thirty-two FAP1 patients belonging to 24 different families were studied for the presence of Val30Met variant by PCR-RFLP. Results: All Brazilian FAP1 subjects studied were positive for the TTR Val30Met variant. As expected, all of them were heterozygous for the mutation. Conclusion: TTR Val30Met mutation was the sole TTR variant found in Brazilian FAP1 patients in this cohort, and it was present even in those subjects without a clear history of Portuguese ancestry.