Patient 2 was a 36-yr-old man presenting with progressive limb muscle weakness, which developed at the age of 20. Initially, he began to have a difficulty in raising his arm above his head and climbing stairs. The weakness was slowly progressive. His mother was noted to have similar symptoms (). His 34-yr-old brother and 39-yr-old sister were not affected clinically. The neurological examination was remarkable for moderate facial weakness; mild (MRC grade 4) and minimal weakness of proximal and distal extremity muscles, respectively; and humeral and quadriceps atrophy. Other remarkable findings included winged scapulae, anterior axillary folds, waddling gait, and hypoactive deep tendon reflexes. The serum creatinine kinase (CK) was 610 IU/L. The forced vital capacity (FVC) was 3.2 L (71% of predicted). Electrocardiogram, echocardiogram, audiogram, and nerve conduction studies were normal. Needle electromyography demonstrated chronic myopathic changes.
Patient 4 was a 46-yr-old man presenting with progressive limb muscle weakness developed in his early twenties. He first noticed a difficulty in raising his arm above his head. There was no known family history of neuromuscular disease in his parents, five sibs, and two daughters (). The neurological examination was remarkable for mild (MRC grade 4) weakness of proximal upper limb muscles and humeral atrophy. Other remarkable findings included anterior axillary folds, asymmetric winged scapulae, trapezius hump sign, Beever's sign, and hypoactive deep tendon reflexes. There was no facial weakness. The serum CK was 170 IU/L. The FVC was 4.19 L (87% of predicted). Electrocardiogram, echocardiogram, and nerve conduction studies were normal. Needle electromyography showed chronic myopathic changes.