A mother and her son with autosomal dominant bulbar spinal muscular atrophy

We reported a 49-year-old mother and her 28-year-old son with autosomal dominantly inherited bulbar spinal muscular atrophy (AD-BSMA). They showed progressive bulbar paresis, muscle wasting and weakness dominant in the proximal groups of limb muscles, and finger tremor. Onset of illness was in adult life. In laboratory examinations, elevated creatine kinase in serum and neurogenic changes either in EMG or muscle biopsy were noted. The son had neither gynecomastia nor abnormal sexual hormone levels which were observed in the sex-linked recessive bulbar spinal muscular atrophy (SR-BSMA). Elongation due to the CAG repeats at the androgen receptor gene of the X chromosome in SR-BSMA was not detected. In conclusion, it is clear that AD-BSMA is different from SR-BSMA on the basis of clinical and genetical aspects.