MRCP2-3153

MRCP2-3153

A 40-year-old man presents with weakness in raising his arms and some drooping of the eyelids. He also has pronounced shoulder blades. He mentions that his symptoms are mild and he may not have noticed them if his father had not experienced similar symptoms that have worsened over time. The patient has no significant medical history and is not taking any regular medications. Upon examination, there is mild evidence of scapula winging, proximal weakness in both upper limbs, ptosis, and difficulty whistling. However, there is normal power in his lower limbs, and his reflexes and sensation are intact throughout.

The patient’s creatine kinase level is 220 units/L. A muscle biopsy has been taken but is still pending. What is the most likely diagnosis?