新复合杂合突变致婴儿型低磷酸酯酶症1例及其家系分析

Infantile hypophosphatasia caused by a novel compound heterozygous mutation: a case report and pedigree analysis

摘要:

该文对1例婴儿型低磷酸酯酶症（HPP）患儿及其家系进行临床特点分析及碱性磷酸酯酶基因（ALPL）检测。先证者，男，5个月，多发骨骼畸形：胸骨凹陷、双侧桡骨弯曲畸形、双膝外翻畸形，伴喂养困难、体重下降、发育迟滞、反复肺炎并呼衰，血碱性磷酸酶显著降低。患儿父母、姐姐、叔父、姨母（其他家系成员未能配合）中除父母及姨母的碱性磷酸酶略低，姨母可见脊柱侧弯畸形，余均无临床表型及实验室异常。患者ALPL基因检测到来源于母亲的c.228delG突变及来源于父亲的c.407G > A复合杂合突变，其姨母携带c.228delG突变。c.407G > A突变为已报道的HPP致病突变，c.228delG为新的致病性突变。低磷酸酯酶症是由ALPL基因突变所致，ALPL基因检测是有效的诊断方法。该研究拓展了ALPL基因突变谱，为HPP的基因诊断提供了理论依据。

Abstract:

This article reported the clinical features of one child with infantile hypophosphatasia (HPP) and his pedigree information. The proband was a 5-month-old boy with multiple skeletal dysplasia (koilosternia, bending deformity of both radii, and knock-knee deformity of both knees), feeding difficulty, reduction in body weight, developmental delay, recurrent pneumonia and respiratory failure, and a significant reduction in blood alkaline phosphatase. Among his parents, sister, uncle, and aunt (other family members did not cooperate with us in the examination), his parents and aunt had a slight reduction in alkaline phosphatase and his aunt had scoliosis; there were no other clinical phenotypes or abnormal laboratory testing results. His ALPL gene mutation came from c.228delG mutation in his mother and c.407G > A compound heterozygous mutation in his father. His aunt carried c.228delG mutation. The c.407G > A mutation had been reported as the pathogenic mutation of HPP, and c.228delG mutation was a novel pathogenic mutation. Hypophosphatasia is caused by ALPL gene mutation, and ALPL gene detection is an effective diagnostic method. This study expands the mutation spectrum of ALPL gene and provides a theoretical basis for genetic diagnosis of this disease.