Mechanism of constipation in familial amyloid polyneuropathy: a case report.

Previously no functional study has been available for the mechanism of constipation in familial amyloid polyneuropathy (FAP). We performed a gut function test in a 78-year-old woman with transthyretin-type FAP who had severe constipation. The gut function test showed a prolonged colonic transit time, a low anal pressure at rest and upon squeezing, loss of the spontaneous phasic rectal contractions, and weak abdominal strain. All these abnormalities suggested a peripheral autonomic dysfunction, corresponding to the enteric neuropathy that was confirmed upon autopsy.