Genetic screening for familial amyloid polyneuropathy in patients with idiopathic carpal tunnel syndrome

Dear Editor, It is well known that patients with transthyretin familial amyloid polyneuropathy (TTR-FAP) type II may have carpal tunnel syndrome (CTS) as the only clinical feature for many years before developing a slowly progressive generalized polyneuropathy with autonomic and cardiac involvement (Plante´-Bordeneuve et al., 1998). This clinical course has been associated with different transthyretin (TTR) mutations (Murakami et al., 1994; Ferlini et al., 1996). In addition, because of the variable penetrance and the frequent late onset, familial amyloid polyneuropathy (FAP) II patients present as ‘sporadic’ cases (Plante´-Bordeneuve et al., 2007). Because CTS is the most frequent entrapment neuropathy with an annual incidence rate between 0.5 and 5.1 per 1,000 (Roquelaure et al., 2008), we evaluated the prevalence of TTR gene mutations in a large sample of patients with CTS without clinical evidence of other diseases. Between June 2005 and Ju