Initial presentation with elevated transaminases and subsequent hematuria in limb-girdle muscular dystrophy type 2B: A case report

Rationale: Limb-girdle muscular dystrophy type 2B (LGMD2B) is a degenerative muscle disorder induced by mutations in the dysferlin gene. Dysferlin is involved in membrane repair and vesicle fusion through its 7 C2 calcium-binding domains, which mediate these calcium-dependent processes. It is currently considered an untreatable neuromuscular condition with a poor prognosis. The estimated incidence of this disease is 1 to 6.5 per 100,000 individuals. The primary clinical features of LGMD2B include proximal muscle weakness and elevated serum creatine kinase (CK) levels; occasionally, patients may present with elevated transaminase and hematuria. It is often misdiagnosed as polymyositis or liver disease. Herein, we report a case of LGMD2B initially presenting with elevated transaminase levels and hematuria. Patient concerns: A 30-year-old woman was found to have elevated transaminases and subsequent hematuria. Diagnoses: The patient was ultimately diagnosed with LGMD2B after muscle biopsy and genetic testing were performed. Interventions: In the patient’s first hospitalization, she was found to have elevated transaminase levels and untested CK levels, and no pathogenic findings were identified after a liver biopsy. Four years later, the patient was admitted to the Nephrology Department with gross hematuria. After hospitalization, serum CK levels were elevated. She was misdiagnosed with polymyositis and treated with oral prednisone; however, her condition did not improve, muscle strength declined, and hematuria persisted. Muscle biopsy and genetic testing were performed, and the patient was ultimately diagnosed with LGMD2B. Supportive therapy with coenzyme Q10, idebenone, and creatine monohydrate was initiated, and she was advised to avoid strenuous physical activity. Outcomes: Currently, the patient exhibits generalized muscle weakness, unstable walking gait, and urine positive (+++) for occult blood. Her muscle strength has gradually declined over the past 13 years. Lessons: LGMD2B initially presents with atypical clinical manifestations. In some cases, elevated transaminase levels can be the first manifestation of the disease; therefore, any unexplained elevated transaminase levels should prompt evaluation of underlying muscle diseases. A 13-year follow-up of a female patient demonstrated progressive muscle atrophy, emphasizing the importance of considering muscle diseases in patients with unexplained elevated serum transaminase levels. Subsequent dark brown urine and hematuria were likely caused by increased myoglobin levels and dysferlin deficiency in podocytes, which may be associated with minimal change nephropathy.