Data on the natural history of facioscapulohumeral dystrophy (FSHD) in childhood are limited and critical for improved patient care and clinical trial readiness. Our objective was to describe the disease course of FSHD in children.

We performed a nationwide, single-center, prospective cohort study of FSHD in childhood assessing muscle functioning, imaging, and quality of life over 2 years of follow-up.

We included 20 children with genetically confirmed FSHD who were 2 to 17 years of age. Overall, symptoms were slowly progressive, and the mean FSHD clinical score increased from 2.1 to 2.8 (p = 0.003). The rate of progression was highly variable. At baseline, 16 of 20 symptomatic children had facial weakness; after 2 years, facial weakness was observed in 19 of 20 children. Muscle strength did not change between baseline and follow-up. The most frequently and most severely affected muscles were the trapezius and deltoid. The functional exercise capacity, measured with the 6-minute walk test, improved. Systemic features were infrequent and nonprogressive. Weakness-associated complications such as lumbar hyperlordosis and dysarthria were common, and their prevalence increased during follow-up. Pain and fatigue were frequent complaints in children, and their prevalence also increased during follow-up. Muscle ultrasonography revealed a progressive increase in echogenicity.

FSHD in childhood has a slowly progressive but variable course over 2 years of follow-up. The most promising outcome measures to detect progression were the FSHD clinical score and muscle ultrasonography. Despite this disease progression, an improvement on functional capacity may still occur as the child grows up. Pain, fatigue, and a decreased quality of life were common symptoms and need to be addressed in the management of childhood FSHD. Our data can be used to counsel patients and as baseline measures for treatment trials in childhood FSHD.

儿童期面肩肱型营养不良 (FSHD) 自然史的数据有限，对于改善患者护理和临床试验准备工作至关重要。我们的目标是描述儿童 FSHD 的病程。

我们对儿童期 FSHD 进行了一项全国性、单中心、前瞻性队列研究，评估了 2 年随访期间的肌肉功能、影像学和生活质量。

我们纳入了 20 名 2 至 17 岁经基因证实为 FSHD 的儿童。总体而言，症状进展缓慢，平均 FSHD 临床评分从 2.1 增加到 2.8（p= 0.003)。进展速度是高度可变的。基线时，20 名有症状的儿童中有 16 名出现面部无力；2 年后，20 名儿童中有 19 名出现面部无力。肌肉力量在基线和随访之间没有变化。最常见和最严重受影响的肌肉是斜方肌和三角肌。通过 6 分钟步行测试测量的功能性运动能力有所提高。全身特征不常见且无进展。腰椎过度前凸和构音障碍等与虚弱相关的并发症很常见，并且在随访期间其患病率有所增加。疼痛和疲劳是儿童常见的主诉，并且在随访期间其患病率也有所增加。肌肉超声检查显示回声逐渐增加。

儿童 FSHD 在 2 年的随访中具有缓慢进展但变化的过程。检测进展最有希望的结果指标是 FSHD 临床评分和肌肉超声检查。尽管有这种疾病进展，但随着孩子的成长，功能能力仍可能会有所改善。疼痛、疲劳和生活质量下降是常见症状，需要在儿童 FSHD 的管理中加以解决。我们的数据可用于为患者提供咨询，并作为儿童 FSHD 治疗试验的基线测量。