1. Diagnosis of dysferlinopathy masked by a superimposed hypothyroid myopathy.
- Author
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Benn KW, Bhalala OG, Day TJ, and French CR
- Subjects
- Humans, Female, Adult, Dysferlin genetics, Electromyography, Diagnosis, Differential, Magnetic Resonance Imaging, Thyroxine therapeutic use, Biopsy, Hashimoto Disease complications, Hashimoto Disease diagnosis, Creatine Kinase blood, Muscular Dystrophies, Limb-Girdle diagnosis, Muscular Dystrophies, Limb-Girdle complications, Hypothyroidism complications, Hypothyroidism diagnosis
- Abstract
We report a woman in her 30s with dysferlinopathy whose diagnosis was masked by superimposed hypothyroidism. Laboratory studies revealed Hashimoto's thyroiditis and markedly raised serum creatine kinase (CK of 6255 U/L; reference range 0-170 U/L). Electromyography, nerve conduction studies and MRI of the hip and thigh were consistent with a diagnosis of hypothyroid myopathy, but thyroxine failed to resolve her clinical presentation or normalise the CK level. Immunohistochemical (IHC) staining of right vastus lateralis muscle biopsy revealed the selective absence of dysferlin leading to a diagnosis of limb-girdle muscular dystrophy type IIB. Dysferlinopathy is a challenging diagnosis due to a varied clinical picture and low incidence. Misdiagnosis is common even in uncomplicated presentations, and this case outlines the need for routine inclusion of IHC and a low threshold for genetic testing, in the workup of complex myopathy., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2024
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