脊髓延髓肌肉萎缩症5例临床分析及分子遗传学诊断

Clinical manifestations and molecular genetics of spinal bulbar muscular atrophy: report of 5 cases

目的分析脊髓延髓肌肉萎缩症(SBMA)的临床表现和辅助检查特点,并作基因诊断。方法收集5例疑似 SBMA 患者的详细病史、体格检查、血液生化、肌电图和肌肉病理等资料,用PCR 方法测定雄性激素受体(AR)基因的 CAG 重复序列拷贝数。结果 SBMA 主要临床表现是四肢肌肉萎缩、无力和肢体震颤,舌肌萎缩和构音障碍;部分患者出现内分泌症状和肌酸激酶(CK)增高。肌电图可见失神经性运动电位。肌肉病理为神经性损害。患者 AR 基因 CAG 重复序列的重复次数均在50次以上,而正常对照是19～24次。结论 SBMA 为中年男性,潜隐起病,主要表现脊髓和延髓肌肉的萎缩和无力,AR 基因 CAG 重复序列的测定有助本病的确诊。

Objective To study the clinical and molecular genetic characteristics of spinal bulbar muscular atrophy （SBMA）. Methods The clinical data, including case history, physical examination, biochemical analyses of blood, EMG, and muscle biopsy, of 5 Chinese patients with SBMA, all males, aged 29-58, with the onset age of 36 （ 17-49 ）, were collected the information of in 5 cases. Four patients underwent PCR to examine the number of copies of CAG repeat region in androgen receptor （AR） gene. Results The clinical characteristics of the 5 patients included atrophy of lingualis, dysarthria, weakness and waste of the limbs, especially in the hands, and elevated cratine kinase （ CK）, fasting glucose, testosterone, and progesterone in the blood. EMG showed denervation motor potentials in all cases. The muscle biopsy in one case showed neurogenic atrophy. The number of （CAG） n repeat in AR gene was 50-62 in the, remarkably from that of 13 normal controls （19-20） without overlapping. Conclusion SBMA affects the middle age males, shows a slowly progressing muscular atrophy in spinal and bulbar muscles. The different number of （CAG） n repeat of AR gene between the SBMA patients and the normal controls may be an important identification to differentiate SBMA from other motor neuron diseases.