Objective: To study the clinical features and gene mutation spectrum of children with sideroblastic anemia (SA) and the clinical value of targeted next-generation sequencing in the molecular diagnosis of children with SA.
Methods: Clinical data were collected from 36 children with SA. Targeted next-generation sequencing was used to detect mutations in SA-related pathogenic genes and genes associated with heme synthesis and mitochondrial iron metabolism. The association between genotype and clinical phenotype was analyzed.
Results: Of the 36 patients, 32 had congenital sideroblastic anemia (CSA) and 4 had myelodysplastic syndrome with ring sideroblasts (MDS-RS). Mutations in CSA-related genes were detected in 19 children (19/36, 53%), among whom 9 (47%) had ALAS2 mutation, 4 (21%) had SLC25A38 mutation, and 6 (32%) had mitochondrial fragment deletion. No pathogenic gene mutation was detected in 4 children with MDS-RS. Among the 19 mutations, 89% (17/19) were known mutations and 11% (2/19) were novel mutations. The novel mutation of the ALAS2 gene c.1153A>T(p.I385F) was rated as "possibly pathogenic" and the novel mutation of the SLC25A38 gene c.175C>T(p.Q59X) was rated as "pathogenic".
Conclusions: ALAS2 and SLC25A38 gene mutations are commonly seen in children with CSA, but mitochondrial gene fragment deletion also accounts for a relatively high proportion. For children with hypoplastic anemia occurring in infancy, mitochondrial disease should be considered.
目的: 对铁粒幼红细胞贫血（SA）患儿的临床特征和基因突变谱进行分析，探讨目的基因捕获二代测序技术在SA患儿分子诊断中的临床应用价值，提高对SA的早期诊断和临床干预水平。
方法: 收集36例诊断为SA患儿的临床资料，采用目的基因捕获二代测序方法进行SA相关致病基因、与血红素合成及线粒体铁代谢有关的基因检测，分析基因型与临床表型的关系。
结果: 36例患儿中，32例为遗传性铁粒幼红细胞贫血（CSA），4例为骨髓增生异常综合征伴环形铁粒幼红细胞（MDS-RS）。共53%（19/36）患儿检测到CSA相关基因突变，其中ALAS2基因突变占47%（9/19），SLC25A38基因突变占21%（4/19），线粒体片段缺失占32%（6/19）。所有MDS-RS患儿均未检测到致病/可能致病性基因突变。89%（17/19）为已知致病突变，11%（2/19）为新变异。ALAS2基因新变异c.1153A > T（p.I385F）评级为"可能致病的"及SLC25A38基因新变异c.175C > T（p.Q59X）评级为"致病的"。
结论: 儿童CSA以ALAS2及SLC25A38基因突变为主，但线粒体基因片段缺失亦占有相当比例，对于婴儿期即出现的低增生性贫血，需考虑线粒体病的可能。