Duchenne and Becker Muscular Dystrophies in Romania: a 10-year Retrospective Study

Abstract

Duchenne muscular dystrophy (DMD) is a rare fatal genetic disorder with a tight correlation between the genotype and the phenotype of the patients. However, the relationship between genotype and phenotype is yet incompletely understood, with some cases manifesting a different phenotype than predicted from their genotype. Since the genetic diagnosis is often targeted to specific gene sections, and the genotype-phenotype correlations guide early treatment decisions, accumulating clinical and epidemiological data for these rare disorders is required to refine local management strategies. This article describes the genotype and phenotype landscape of 239 patients treated in the Pediatric Neurology Clinic of the Clinic Psychiatry Hospital ”Prof. Dr. Alexandru Obregia” in Bucharest, using randomly collected data from a ten-year interval (2012–2022). It revealed a significant improvement in the quality of care, highlighted by a notable reduction in the average age at diagnosis in recent years, although considerable variability remains across counties. The study identified three mutations that were not previously described in the Edystrophin or TREAT-NMD DMD Global Database. The accuracy of the Reading-Frame rule was 88.4 % for deletions. For exceptions from the rule, the involvement of different isoforms, binding domains, structural domains, and the disturbance of the three-dimensional structure of the rod domain were not reliable indicators of the phenotype. 12.9 % of all patients had nonsense mutations with a DMD phenotype that could benefit from Ataluren treatment within the National Treatment Program, and 15 % were eligible for exon-skipping therapies, with exon 51 having the broadest applicability (7.1 %).