摘要目的: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。

abstractsObjective: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.