Limb-Girdle Muscular Dystrophy Type 2B and Morbihan Disease: A Case Report With an Atypical Presentation

This case report presents a 38-year-old man with no significant medical history who was referred to the Internal Medicine Department due to dermatosis and muscle weakness. A multidisciplinary diagnostic approach was initiated, including laboratory, imaging, and even histopathological studies. No definitive diagnosis was obtained. During the diagnostic process, the patient's clinical course was torturous, with evidence of increasing muscle weakness and inability to walk. Due to the lack of a definitive diagnosis, empirical treatment with systemic steroids was initiated, with no clinical evidence of improvement. After ruling out a neoplastic or autoimmune cause, a molecular panel for muscular dystrophies was performed, which identified NM_003494 (DYSF_v001): c.1382T>C; p.(Ile461Thr), a clinically pathogenic and heterozygous variant. This led to the diagnosis of limb-girdle muscle dystrophy type 2B with no evidence of association with dermatosis, consistent with Morbihan disease. Molecular diagnosis was crucial for an accurate diagnosis and thus enabled the implementation of therapeutic strategies aimed at improving the patient's quality of life. Muscular dystrophy type 2B is a disease that still lacks specific treatment and can progress to the point of disability. The patient was fully informed about the progression and prognosis of muscular dystrophy and was referred for physical rehabilitation with the goal of delaying permanent disability. Regarding Morbihan disease, the patient received the prescribed treatment for eight months, with notable improvement in edema and dermatological lesions.