Clinical Reasoning: Progressive Proximal Weakness in a 61-Year-Old Male.

A 61-year-old man presents with painless progressive weakness and was found to have myopathy both clinically and on diagnostic workup.The etiology of his myopathy is the first reported case of anti-SRP myopathy and sarcoidosis overlap syndrome. The high titer anti-SRP antibody and phenotype support the diagnosis of an overlap syndrome, defined as multiple distinct autoimmune diseases occurring together.This case highlights the wide differential for myopathies and the different testing and components to consider when approaching a diagnosis.