Usefulness of labial salivary gland biopsy in familial amyloid polyneuropathy Portuguese type

Background. The diagnosis of amyloidosis of all types is definitively made by demonstration of Congo red binding material in the affected tissues. Nerve biopsy was classically used to diagnose amyloid polyneuropathy but less invasive alternative types of biopsies have been proposed including labial salivary gland (LSG) biopsy, a minimally invasive procedure. Method. LSG biopsies were done in 87 subjects with molecular diagnosis of TTRVal30Met mutation. The group includes 76 patients in different stages of familial amyloid polyneuropathy and 11 asymptomatic carriers. They were all submitted to a stomatological and a neurological observation to evaluate oral health problems and to determine the neurological stage of the disease. No major oral health problems were found. Mean age of onset of the symptomatic disease was 32.8 years (+/-9.69 SD). Conclusions. No significant side effects occurred after the surgical procedure, and adequate material for pathological analysis was always obtained. Amyloid deposition was found in 91% of the patients. Patients with negative biopsies (N = 7) were all in the earlier stage of the disease. Two asymptomatic carriers had biopsies with amyloid deposition. We conclude that LSG biopsy is a useful, sensitive and minimal invasive method to detect amyloid deposition.