Minor salivary gland biopsy for the diagnosis of familial amyloid polyneuropathy

Abstract

The diagnosis of Val30Met familial amyloidotic polyneuropathy (FAP) is based on genetic tests, clinical manifestations, familial history and biopsy of peripheral tissues (e.g. rectum, abdominal fat pad, sural nerve, and minor salivary gland) to confirm the presence of amyloid deposits. The aim of this study was to determine the frequency of amyloid deposits in minor salivary glands biopsied from FAP patients and to investigate whether an association exists between the presence of these deposits and clinical features. Seventeen patients with FAP were submitted to minor salivary gland biopsy to confirm the presence of amyloid deposits. The histopathology of the salivary glands confirmed glandular amyloid deposits in nine symptomatic patients (sensitivity of 75.0%). In general, FAP patients who tested positive for glandular amyloid deposits exhibited significantly higher frequencies of sensorimotor and dysautonomic dysfunctions (p = 0.001) compared with those who tested negative. None of the patients reported xerostomia. Minor salivary gland biopsy may help confirm the diagnosis of FAP in symptomatic cases, as it is noninvasive, easy to execute, and causes minimal discomfort to patients.

Keywords: Familial amyloidotic polyneuropathy; Minor salivary gland biopsy; Transthyretin mutation.