Department of Nephrology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China.
Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China.
Orphanet J Rare Dis. 2023 Jul 21;18(1):199. doi: 10.1186/s13023-023-02806-2.
BACKGROUND & AIMS: Fabry disease (FD) is a rare X-linked metabolic storage disorder due to the deficiency of lysosomal α-galactosidase A which causes the accumulation of glycosphingolipids throughout the body. Underweight and low BMI have been occasionally reported in FD patients previously. Whether underweight is common in the early stage of FD and body composition analysis to determine the cause have not been reported.
Children who were diagnosed with FD in the Children's Hospital of Zhejiang University School of Medicine from July 2014 to December 2022 were enrolled. Clinical data were obtained from medical records. Whole body dual energy X-ray absorptiometry scans (DXA) were used to assess body composition (fat mass, FM; fat free mass, FFM and bone mass) according to the International Society of Clinical Densitometry's standard operating method. Whole body muscle mass was calculated as fat-free mass minus bone mass. Appendicular skeletal muscle mass (ASM) was calculated as the sum of the arm and the leg muscle mass. The FM, FFM, ULSM and LLSM indices were calculated by dividing the total FM, FFM, and upper and lower limb skeletal muscle mass (ULSM and LLSM) by the height squared.
A total of eighteen children (14 boys and 4 girls) were enrolled. Thirteen boys had the classical phenotype, and five children (1 boy with the N215S mutation and 4 girls) had the late-onset phenotype. Seven children with the classical phenotype (53.8%) and two of the five children (40%) with the late-onset phenotype had abnormal BMIs. Sixteen of the eighteen children (88.9%) had a height in the normal range, suggesting that low BMI was mainly due to underweight. By DXA body composition analysis, the FMI was abnormal in 3 children (2 boys and 1 girl), and the FFMI was abnormal in 12 children (9 boys and 3 girls). For the classical phenotype, 2 of the 13 children (15.4%) had abnormal FMI values, while 10 (76.9%) had abnormal FFMI values. Eight patients (61.5%) with the classical phenotype had a significant reduction in muscle mass index, ASM index and LLSM index values compared with age- and sex- matched Chinese controls. Late-onset patients also had mild low skeletal muscle mass compared to controls. The results suggested that low skeletal muscle mass is common in early FD.
This is the first study to examine body composition and muscle mass in early Fabry disease patients. Low skeletal muscle mass is a common early symptom in children with Fabry disease, suggesting that skeletal muscle is significantly affected in the early stages of FD.
法布里病（FD）是一种罕见的 X 连锁代谢贮积病，由于溶酶体α-半乳糖苷酶 A 的缺乏，导致糖脂在全身积累。此前，FD 患者偶尔会出现体重过轻和低 BMI。体重过轻是否在 FD 的早期阶段很常见，以及是否进行过身体成分分析以确定原因，这些尚未有报道。
本研究纳入了 2014 年 7 月至 2022 年 12 月期间在浙江大学医学院附属儿童医院被诊断为 FD 的患儿。研究从病历中获取临床数据。根据国际临床密度测定协会的标准操作方法，使用全身双能 X 射线吸收仪（DXA）评估身体成分（脂肪量，FM；去脂体重，FFM 和骨量）。全身肌肉量计算为去脂体重减去骨量。四肢骨骼肌量（ASM）计算为手臂和腿部肌肉量的总和。通过将总 FM、FFM 和上下肢骨骼肌质量（ASM 和 LLSM）除以身高平方来计算 FM、FFM、ULSM 和 LLSM 指数。
共纳入 18 名儿童（14 名男孩和 4 名女孩）。13 名男孩为经典表型，5 名儿童（1 名男孩携带 N215S 突变，4 名女孩）为晚发型表型。7 名经典表型男孩（53.8%）和 5 名晚发型表型儿童中的 2 名（40%）BMI 异常。18 名儿童中的 16 名（88.9%）身高处于正常范围，提示低 BMI 主要是由于体重过轻。通过 DXA 身体成分分析，3 名儿童（2 名男孩和 1 名女孩）存在 FMI 异常，12 名儿童（9 名男孩和 3 名女孩）存在 FFMI 异常。对于经典表型，13 名儿童中有 2 名（15.4%）FMI 值异常，10 名（76.9%）FFMI 值异常。8 名（61.5%）经典表型患儿的肌肉质量指数、ASM 指数和 LLSM 指数值与年龄和性别匹配的中国对照组相比显著降低。晚发型患者的骨骼肌质量也比对照组低。结果表明，低骨骼肌质量在早期 FD 中很常见。
这是第一项研究早期法布里病患者身体成分和肌肉质量的研究。在患有法布里病的儿童中，低骨骼肌质量是一种常见的早期症状，这表明在 FD 的早期阶段，骨骼肌受到了显著影响。
