低碱性磷酸酶血症六例临床和基因分析

Clinical follow-up and genetic analysis of six cases with hypophosphatasia

目的:分析低碱性磷酸酶血症(HPP)患儿的临床特点、基因变异类型及随访资料。方法:回顾性总结分析2010年10月至2019年1月北京儿童医院内分泌遗传代谢中心收治的6例HPP患儿的临床资料,并对其中5例患儿及家系进行致病基因测序分析,总结其临床特点和基因变异类型及转归。结果:6例HPP患儿中男5例、女1例,年龄2月龄至6岁4月龄,血碱性磷酸酶均明显降低(2~49 U/L),婴儿型4例、儿童型与牙型各1例。婴儿型患儿均有纳差、体重增长缓慢及高钙血症,儿童型与牙型患儿均有牙齿脱落,儿童型患儿伴有跛行等运动功能改变。5例患儿及其中4个家系发现10个组织非特异性碱性磷酸酶基因变异,7个错义变异,1个插入变异,1个移码变异,1个缺失变异,其中3个为新发变异(p.Y28C、p.268,F>L、p.A176V)。4例婴儿型HPP患儿中3例死亡,1例好转后失访,儿童型和牙型HPP患儿经治疗后好转。结论:HPP各型之间的临床表现变异性大又相互重叠,儿童型及牙型预后较好,婴儿型预后较差,基因检测是明确诊断的主要方法。

ObjectiveTo analyze the clinical, genetic characteristics and follow-up data of Chinese patients with hypophosphatasia (HPP).MethodsA retrospective analysis was conducted on six children with HPP admitted to the Department of Endocrinology, Genetics and Metabolism in Beijing Children′s Hospital from October 2010 to January 2019. Summarized the clinical and follow-up data of all six patients, as well as the pathogenic variants of five children.ResultsThe serum alkaline phosphatase levels of all six children (five males and one female) were significantly reduced (2-49 U/L). The 6 patients aged from 2 months to 6 years and 4 months, 4 infantile HPP, 1 childhood HIP and 1 odonto HPP. The four patients with infantile HPP presented with anorexia, slow weight gain and hypercalcemia, whereas the one patient with childhood HPP and the other patient with odonto HPP had tooth loss. The patient with childhood HPP also manifested with motor dysfunction. Genetic testing was conducted for five patients and 4 unrelated Chinese families and revealed 10 variations in ALPL gene, including 7 missense variation, 1 insertion variation, 1 frameshift variation, 1 deletion variation.Of which 3 were novel (p.Y28C, p.268, F>L, p.A176V).One of the infantile patients lost follow-up and the other three deceased. The clinical conditions were much improved with medical intervention for patients with childhood, orodonto HPP.ConclusionsWhile HPP patients with different ages of onset present with common features, the prognosis differ significantly. The prognosis is good for patients with childhood, orodonto HPP and poor for patients with infantile HPP. Genetic testing is the main method for definitive diagnosis.