Initial laboratory studies revealed normal thyroid function, a creatine kinase (CK) level of 83 U/L (reference range, 30-135 U/L) (to convert to microkatals per liter, multiply by 0.0167), and a serum angiotensin-converting enzyme (ACE) level of 58 U/L (reference range, 8-53 U/L) (to convert to nanokatals per liter, multiply by 16.667). Renal parameters were consistent with end-stage renal failure, with a serum creatinine level of 5.6 mg/dL (reference range, 0.60-1.20 mg/dL) (to convert to micromoles per liter, multiply by 88.4) and a glomerular filtration rate of 12 mL/min/1.73 m2. Results of routine cerebrospinal fluid (CSF) studies, including CSF ACE level, were unremarkable. Other laboratory test findings, including vitamin B12 level, human immunodeficiency virus serology, antinuclear antibody, serum protein electrophoresis with immunofixation, acetylcholine receptor and muscle-specific kinase antibodies, and paraneoplastic antibody titers, were nonrevealing. Pulmonary function test findings revealed a severe restrictive pattern deficit consistent with neuromuscular weakness. Chest computed tomographic scan revealed evidence of chronic granulomatous disease.