Hereditary sensory and autonomic neuropathy type I

Introduction

Hereditary sensory and autonomic neuropathy (HSAN) type 1 is an autosomal dominant disorder belonging to group of hereditary sensory and autonomic neuropathies which are genetic neuronal or axonal diseases with predominant involvement of peripheral sensory neurons and some degree of motor or autonomic impairment.[1] In HSAN I, there is dissociated sensory loss with loss of pain and temperature and retention of touch sensation. Symptoms start during second or later decades when callosities develop on plantar surface of toes and under the metatarsal heads. Sensory loss results in repeated formation of painless ulcers and blisters on callosities due to trauma. At times cellulitis or lymphangitis can be associated and osteomyelitis can results in acral mutilation.[2] Sensory loss and infections of fingers and hands are less common than in HSAN II. After treatment of ulcers, prevention of recurrent fool ulcers with comfortable shoes is most important.[3] We report here two brothers, one 17 years and another 14 years old, who started developing callosities at age of 9-10 years and later developed ulcers with repeated episodes of infection, cellulitis, lymphangitis with progressive mutilation.

Case Reports

Case 1. One 17 years male presented with multiple, big ulcers on the soles especially over head of metatarsals on both feet with contractures, acral mutilation with deformed toes. Ulcers had firm and sharp margins and floor of ulcer had pinkish granulation tissue with serous discharge. At places, underlying muscles and tendons were exposed. Dorsa of feet had pigmentation, thickening of skin and multiple irregular fibrous plaques and chronic recurrent lymphoedema of feet and lower legs. Pain, superficial touch and temperature perception were diminished over distal parts of both legs while vibration and position perception was almost normal. Ankle jerk was absent. Hands and arms were normal and there was no thickening of peripheral cutaneous nerves. There was no peroneal muscles atrophy, hearing and vision were normal. Parents were healthy and this marriage was non-consanguineous.

Case 2. One 14 years old boy had loss of sensation in both feet and difficulty in walking since the age of 11 years. Examination revealed painless, big, deep ulcers, 6cm x 4.5cm with sharp margins, on left foot over the heads of metatarsals. Floor of ulcer showed red granulation tissue and visible underlying muscles and tendons. Also present were scars of old ulcers, pigmentation and thickening of skin with scars and contractures of right foot. Thermal and pain sensations were gone and tactile sensations were intact. Ankle jerk was absent. Hands were normal. Peripheral cutaneous nerves were non-thickened and non-tender. General and systemic examinations were normal. Their 9 years old borther was normal and no other member of family had any problem.

Discussion

HSAN-1 is a rare disease. Onset of symptoms in the second decade, dissociated sensory loss, absence of ankle jerk and non healing ulcers in the feet with relative sparing of hands in our both cases met criteria for HSAN-1 category of Dyck and Ohta.[4] The only way of helping these patients is by early detection of disease and proper care of anaesthetic feet with prevention of repeated trauma and infection and these measures can enable these patients to lead almost a normal life.