Distrofia Muscular de Becker na População Pediátrica: Diagnóstico, Variabilidade Genética e Progressão da Doença

Introduction: Becker muscular dystrophy (BMD) is an X-linked neuromuscular disease caused by variants in the DMD gene, leading to progressive muscle weakness, dilated cardiomyopathy, and neurodevelopmental disorders. Objective: To characterize patients with BMD from a pediatric neuromuscular center. Methods: Retrospective and descriptive study of BMD patients diagnosed between January 1995 and May 2024. Demographic and clinical data were analyzed using SPSS®. Results: A total of 22 male cases were identified, with 9/22 reporting a family history (n=9). First symptoms appeared at a median age of 3 years (IQR 4.5). Initial clinical presentation included unstable gait (5/22), fatigue (5/22), myalgias (4/22), asymptomatic elevation of CK (3/22), delayed motor development (3/22), and myoglobinuria (2/22). Average age at diagnosis was 7.7 years (SD 3.9). A deletion involving exon 48 of the DMD gene was the most frequent genetic alteration (8/22). Developmental disorders included: intellectual disability (5/22), attention-deficit/hyperactivity disorder (3/22), autism spectrum disorder (1/22), and specific language impairment (1/22). A case of dilated cardiomyopathy developed during pediatric age. Three patients started corticosteroid therapy due to worsening motor symptoms. The average follow-up time was 8.7 years (SD 1.1). Conclusion: The phenotypic variability of BMD complicates diagnosis, but early recognition is crucial for appropriate monitoring and genetic counselling, and family studies. Our findings highlight the need for multidisciplinary follow-up, particularly due to the significant prevalence of neurodevelopmental disorders.