Bethlem myopathy: case report in a 7-year-old patient

*Correspondence: [e-mail].

Eduardo Ferraz Troijo,^1* Pedro Zambusi Naufel,¹ Rafael Guerra Cintra¹

Abstract

Case Presentation: ELS, 7 years old, third child of a non-consanguineous couple, with no relevant gestational or neonatal history, with difficulty walking since walking, with worsening in the last year. Relevant family history of great-uncle with similar condition, without diagnosis. Evaluated by our team, at 7 years of age. At the neurological examination in the first consultation, she presented contracture in the distal portion of the lower limbs, affecting both feet, being more evident on the right. Proximal and distal muscle weakness, with distal predominance and difficulty in performing fine movements with both hands, due to interphalangeal muscle contracture. Positive Gowers maneuver. The patient had laboratory tests with elevated CPK (973- VR:190). During the clinical evolution, muscular atrophy of the limbs and the presence of keloids on both knees were noticed. A diagnostic hypothesis of myopathy was suggested, and genetic investigation was carried out resulting in Muscular Dystrophy associated with the COL6A2 gene - position chr 21:46,125,776, variation G>A.

Discussion: Given the clinical picture presented, the patient has dystrophy related to collagen IV, with genotypes associated with alterations molecular changes in the COL6A1, COL6A2 and COL6A3 genes. These mutations are responsible for varied phenotypes, including Ullrich congenital muscular dystrophy (CUDM) and Bethlem myopathy (MB). Bethlem myopathy tends to have a benign course, with the main characteristic being early contractures of the interphalangeal joints and elbows, joint hypermobility, muscle weakness and formation of keloid scars. However, some reports reveal that Bethlem myopathy can evolve progressively to stop walking. Histopathological findings are usually compatible with dystrophic changes and creatine kinase levels may be normal or mildly elevated, like the patient in question. Ullrich's congenital muscular dystrophy is described as disabling and potentially lethal dystrophy, leading to death mainly due to respiratory complications. Within the phenotype of dystrophies with changes in collagen IV, the patient fits Bethlem's dystrophy, due to its more benign progression and the phenotype presented.

Final Comments: The case presented above demonstrates phenotypic changes compatible with the disease described and due to the population prevalence and early onset of the condition, this case report was chosen

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Artikel online veröffentlicht:
12. Mai 2025