To determine the prevalence of V122I mutation in African Americans with bilateral carpal tunnel syndrome.  

To explore whether cardiac and neuropathy symptoms affect the likelihood of having V122I mutation in African Americans with bilateral carpal tunnel syndrome. 

Hereditary transthyretin (hTTR) amyloidosis can cause diseases of multiple organ systems.  There are many known mutations of the transthyretin (TTR) gene.  The V122I mutation has a prevalence of 3-4% in the African American population.  This mutation is associated with hTTR amyloid cardiomyopathy, as well as polyneuropathy and dysautonomia.  Previous studies showed 29 to 47% of the patients with V112I mutation had a history of carpal tunnel syndrome (CTS) by the time they were diagnosed with cardiomyopathy.  This raises the question of whether we should screen for this mutation in African American individuals with bilateral carpal tunnel syndrome, and whether early identification of the mutation would have an impact on disease outcome.

African American adult patients without history of amyloidosis and diagnosed with bilateral carpal tunnel syndrome are recruited for the study.  They received genetic testing to screen for TTR mutation. They received questionnaires to screen for symptoms of cardiomyopathy, neuropathy and dysautonomia. 

Two of the sixteen patients (12.5%) with bilateral CTS had the V122I mutation.  The rest of them had no TTR mutation.  The patients with V122I mutation were not more likely to have symptoms of cardiomyopathy, polyneuropathy and dysautonomia than those without TTR mutation. 

The prevalence of TTR mutation in African Americans with bilateral CTS may be greater than the 3-4% in the general African American population.  The likelihood of African Americans with bilateral CTS having V122I mutation may be independent of cardiomyopathy, neuropathy and dysautonomia symptoms.  A larger study is required to verify these conclusions.  Additional studies are required to determine if early identification V122I mutation would affect disease outcome.