Department of Pediatrics, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima 7348511, Japan.
Department of Orthopeadic Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 7348551, Japan.
Int J Mol Sci. 2020 Feb 2;21(3):989. doi: 10.3390/ijms21030989.
Morquio A syndrome, mucopolysaccharidosis type IVA (MPS IVA), is a lysosomal storage disorder caused by the deficient activity of N-acetylgalactosamine-6-sulfatase (GalNac6S), due to alterations in the gene. This disorder results in marked abnormalities in bones and connective tissues, and affects multiple organs. Here, we describe the clinical course of a Japanese boy with MPS IVA who began enzyme replacement therapy (ERT) at the age of 24 months.
the patient presented for kyphosis treatment at 22 months of age. An X-ray examination revealed dysostosis multiplex. Uronic acids were elevated in the urine and the keratan sulfate (KS) fraction was predominant. The leukocyte GalNac6S enzyme activity was extremely low. The patient exhibited the c.463G > A (p.Gly155Arg) mutation in . Based on these findings, his disease was diagnosed as classical (severe) Morquio A syndrome. An elosulfase alfa infusion was initiated at the age of 24 months. The patient's body height improved from -2.5 standard deviation (SD) to -2 SD and his physical activity increased during the first 9 months on ERT. However, he gradually developed paralysis in the lower legs with declining growth velocity, which required cervical decompression surgery in the second year of the ERT. The mild mitral regurgitation, serous otitis media, and mild hearing loss did not progress during treatment.
early initiation of the elosulfase alfa to our patient showed good effects on the visceral system and muscle strength, while its effect on bones appeared limited. Careful observation is necessary to ensure timely surgical intervention for skeletal disorders associated with neurological symptoms. Centralized and multidisciplinary management is essential to improve the prognosis of pediatric patients with MPS IVA.
黏多糖贮积症 IVA 型（MPS IVA）又称 Morquio A 综合征，是一种溶酶体贮积病，由 N-乙酰半乳糖胺-6-硫酸酯酶（GalNac6S）活性缺乏引起，该酶的缺乏是由于 基因突变所致。这种疾病导致骨骼和结缔组织明显异常，并影响多个器官。在此，我们描述了一名 24 个月大开始酶替代治疗（ERT）的日本男孩的临床病程。
22 个月大时因脊柱后凸就诊。X 线检查显示多发性骨发育不良。尿液中存在过多的尿嘧啶单糖，硫酸角质素（KS）占主导地位。白细胞 GalNac6S 酶活性极低。患者在 基因中存在 c.463G > A（p.Gly155Arg）突变。根据这些发现，他被诊断为经典（重度）黏多糖贮积症 IVA 型。24 个月大时开始输注艾度硫酸酯酶。ERT 治疗的前 9 个月，患者的身高从-2.5 个标准差（SD）增加到-2 SD，身体活动能力增强。然而，他逐渐出现下肢瘫痪，生长速度下降，ERT 第二年需要进行颈椎减压手术。治疗期间，轻度二尖瓣反流、浆液性中耳炎和轻度听力损失没有进展。
早期开始使用艾度硫酸酯酶治疗我们的患者，对内脏系统和肌肉力量有良好的效果，而对骨骼的效果似乎有限。需要仔细观察，以确保及时进行与神经症状相关的骨骼疾病的手术干预。集中和多学科管理对于改善 MPS IVA 儿科患者的预后至关重要。
