Case report and literature review: Fabry disease misdiagnosing as polymyalgia rheumatica.

Rationale: The clinical manifestations of Fabry disease affect the nerves, kidneys, heart, skin, gastrointestinal tract and eyes. Our aim is to familiarize people with the FD diagnostic process by reporting this case.

Patient Concerns: A 79-year-old-male patient presented with muscle pain and weakness in the extremities, also with an increasing erythrocyte sedimentation rate and C-reactive protein. Further examinations revealed that multiple organ involvement, such as rash, myocardial hypertrophy, peripheral neuropathy.

Diagnoses: Cardiac MR demonstrated hypertrophic cardiomyopathy, myocardial fibrosis and low myocardial T1 value. The patient was eventually diagnosed with Fabry disease through proteomics and genetic testing.

Interventions: The treatment is enzyme replacement therapy (ERT). But this patient could not afford ERT and was given only general symptomatic treatment, pregabalin, and a gradual reduction in glucocorticoid.

Outcomes: The patient's symptoms of joint pain and muscle weakness reduced significantly, and ESR and CRP had decreased to normal.

Lessons: FD is a rare disease and difficult to diagnose, but rare does not mean invisible. FD may present with signs and symptoms of rheumatic diseases. Rheumatologists should be aware and concerned about this disease.