Distribution of CAG repeat number within androgen receptor gene in Chinese Han nationality and its application in genetic diagnosis for Kennedy's disease / 中华老年医学杂志

ABSTRACT

Objective To investigate the distribution of androgen receptor (AR) gene CAGrepeats in the Chinese Han nationality and its application in genetic diagnosis for Kennedy's disease (KD). MethodsRT-PCR,denaturing polyacrylamide gel electrophoresis (DPAGE) and gene sequencing were conducted for AR gene CAG repetition among 100 healthy controls and 28 patients diagnosed as motorneuron diseases,and the number of the repetition was counted. Results The healthy controls had a range of 15-31 times of CAG repetition,with an average of (23 ± 3) times.Among patients with motoneuron disease,3 cases with CAG repetition for more than 40 times (namely,46,47 and 47 times) were diagnosed as KD.The main clinical manifestations included slow progress of limb weakness,primarily in the proximal lower limbs,fatigue accompanied by myalgia,muscle jumping,muscle atrophy,elevated serum creatine kinase (CK) levels,neurogenic damage revealed by electromyogram (EMG) and androgen insensitivity.Conclusions The incidence of KDmay be underestimated in the Chinese population.Performing genetic diagnosis in patients with motor neuron disease for AR gene can improve clinical diagnosis and avoid misdiagnosis.