Clinical, electrophysiological and molecular genetic features of Kennedy disease

Abstract

Objective To explore the clinical, electrophysiological and molecular genetics features of Kennedy disease (KD) which might contribute to early diagnosis and avoid misdiagnosis of KD. Methods The clinical and electrophysiological data of 13 patients with KD, admitted to our hospital from December 2013 to March 2018, were retrospectively analyzed. The (CAG) repeats in the exon 1 of androgen receptor (AR) gene were conducted by capillary electrophoresis. Results All patients appeared chronic course. Progressive weakness of limbs and muscular atrophy, including lingual muscle and bulbar muscle, were the specific clinical characteristics. Ten patients presented with barymastia and 11 patients with hormonal imbalance. Electromyography (EMG) showed decline of sensory nerve action potential amplitude in most patients. A widespread neuronal damage, such as increased duration of motor unit action potential, fibrillation potential, fascicular potential and positive sharp wave, could be detected. AR gene mutations were detected in all 13 patients. The number of (CAG) repeats expansion in exon 1 of AR gene ranged from 40 to 54. Conclusions The impairment of lower motor neuron, bulbar palsy and hormonal imbalance are the main clinical features in patients with KD. EMG shows chronic widespread neuronal damage. AR gene mutation detection plays a vital role in the final diagnosis of KD. Key words: Kennedy disease; Electrophysiology; Androgen receptor gene