128. Functional and morphological demonstration of autonomic nervous system involvement in HSAN type II

Abstract

The assessment of autonomic nervous system (ANS) in hereditary sensory autonomic neuropathy (HSAN) type II is still lacking. To this aim we investigated the ANS involvement in a new family with HSAN II phenotype. Three siblings from non consanguineous healthy parents were clinically and electrophysiologically evaluated. Two of them underwent quantitative sensory testing (QST), cardiovascular and dynamic sweat tests and skin biopsy. Genetic testing for WNK1 and FAM134B mutations is ongoing. Onset occurred in the first decade, with impaired pain sensitivity and progressive distal mutilating ulceration with amputation and joint deformity. Autonomic disturbances included hypohidrosis with heat intolerance, pupillary abnormalities and chronic diarrhoea. Nerve conduction studies showed a severe axonal sensory neuropathy. Sympathetic skin response was absent. QST was altered for both painful and nonpainful sensory modalities. Autonomic functional studies detected the impairment of both sudomotor and cardiovascular systems. Skin biopsy revealed a lack of epidermal and dermal sensory and autonomic nerve fibers with complete denervation of sweat glands and arteriovenous anastomoses. Our findings expand the HSAN II phenotype providing pathological and functional evidence of a widespread ANS impairment. The complete sensory and arteriovenous denervation accounts for the severe sensory loss and distal ulcerations in HSAN type II.