The aim of this prospective multicentric study was to document disease progression in young boys affected by Duchenne muscular dystrophy (DMD) between age 3 and 6 years (±3 months) using the North Star Ambulatory Assessment scale. One hundred fifty-three DMD boys (573 assessments) younger than 6 years (mean: 4.68, SD: 0.84) with a genetically proven DMD diagnoses were included. Our results showed North Star Ambulatory Assessment scores progressively increased with age. The largest increase was observed between age 3 and 4 years but further increase was steadily observed until age of 6 years. Using a multiple linear regression analysis, we found that both the use of corticosteroids and the site of mutation significantly contributed to the North Star Ambulatory Assessment changes (p < 0.001). At each age point, boys on corticosteroid treatment had higher scores than corticosteroid naïve ones (p < 0.001). Similarly, patients with mutations downstream exon 44, had lower baseline scores and lower magnitude of changes compared to those with mutations located at the 5' end of the gene (p < 0,001). Very few boys achieved the age appropriate maximum score. These results provide useful information for the assessment and counselling of young DMD boys and for the design of clinical trials in this age group.

中文翻译：

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杜氏肌营养不良症年轻男孩的纵向自然病程

这项前瞻性多中心研究的目的是使用北极星动态评估量表记录 3 至 6 岁（±3 个月）受杜氏肌营养不良症 (DMD) 影响的年轻男孩的疾病进展。153 名 6 岁以下的 DMD 男孩（573 次评估）（平均值：4.68，标准差：0.84）被纳入经基因证实的 DMD 诊断。我们的结果显示北极星动态评估分数随着年龄的增长而逐渐增加。最大的增加出现在 3 到 4 岁之间，但在 6 岁之前稳定地观察到进一步增加。使用多元线性回归分析，我们发现皮质类固醇的使用和突变位点都对北极星动态评估的变化有显着影响（p < 0.001）。在每个年龄段，接受皮质类固醇治疗的男孩比未使用皮质类固醇的男孩得分更高（p < 0.001）。同样，与位于基因 5' 端突变的患者相比，外显子 44 下游突变的患者基线评分较低，变化幅度较小（p < 0,001）。很少有男孩达到与年龄相符的最高分。这些结果为年轻 DMD 男孩的评估和咨询以及该年龄组的临床试验设计提供了有用的信息。