一例15q11.2微重复患儿的临床及遗传学分析

目的明确1例发育迟缓、智力低下患儿遗传学病因及其来源,并对该家系下一胎行产前诊断。方法采集患儿及其父母外周血进行常规G显带核型分析及单核苷酸多态性微阵列芯片(single nucleotide polymorphism array,SNP array)检测;并对该孕妇行产前诊断,进行羊水细胞染色体核型分析及SNP array检测。结果患儿及其父母染色体核型未见异常。SNP array检测结果显示患儿15号染色体15q11.2区段存在855.3 kb重复,该重复遗传至表型正常的母亲,父亲检测结果未见异常。孕妇羊水细胞染色体核型及SNP array检测结果均未见异常。结论15q11.2微重复可能与体格/智力发育障碍相关,CYFIP1可能是其候选基因,但该重复仅可增加其发病风险,外显率较低,在临床咨询中应引起重视。

Clinical and genetic study of a child with 15q11.2 microduplication

Objective To explore the genetic basis of a child with developmental delay and intellectual disability.Methods Peripheral blood samples of the child and his parents were collected for routine G-band karyotyping analysis and single nucleotide polymorphism array(SNP array)assay.Amniotic fluid sample was collected during the next pregnancy for prenatal diagnosis.Results No karyotypic abnormality was found in the child and his parents.SNP array showed that the child has carried a 855.3 kb microduplication in 15q11.2.His mother carried the same duplication but had no phenotypic anomaly.No microdeletion/microduplication was found in his father.Upon prenatal diagnosis,no abnormalities was found with the chromosomal karyotype and SNP array result of the fetus.Conclusion 15q11.2 microduplication may result in developmental delay and intellectual disability,for which CYFIP1 may be a candidate gene.However,the duplication may increase the risk but with a low penetrance.This should attract attention during clinical consultation.