目的:明确1例生长发育迟缓患者的遗传学病因。方法:收集患者的症状、体征等临床资料，常规应用G和C显带分析患者及父母外周血染色体，然后采用单核苷酸微阵列(single nucleotide polymorphisms array, SNP-array)技术进一步确诊，并采用荧光定量PCR(fluorescence quantitative polymerase chain reaction，qPCR)验证。结果:患者染色体核型为46, XX, r(15)(p11.2q26.3)[92]/45, XX，-15[9]/46, XX, dic r(15)(p11.2q26.3；p11.2q26.3)[4]；SNP-array提示arr[hy19]15q26.3(98 957 555-102 429 040)×1，考虑染色体15q26.3区存在约3.4 Mb的杂合性缺失，缺失片段中包含致病性明确的n IGF1R等7个Morbid基因；qPCR验证结果为15号染色体n IGF1R基因第3、10和20外显子引物扩增区存在缺失，考虑系包含了n IGF1R基因的片段杂合性缺失所致。患者父母核型正常。n 结论:15q26.3区域的微缺失导致n IGF1R等基因单倍剂量不足以及环状染色体的不稳定，这可能与患者生长发育迟缓等临床特征相关，细胞分子水平的检查为病因学诊断提供了依据。n “,”Objective:To explore the genetic basis for a patient featuring developmental delay.Methods:The patient and her parents were subjected to G- and C-banded chromosomal karyotyping analysis. The proband was also analyzed by single nucleotide polymorphism microarray (SNP-array). The result was verified by using fluorescence quantitative PCR (qPCR).Results:The proband’s karyotype was ascertained as 46, XX, r(15)(p11.2q26.3)[92]/45, XX, -15[9]/46, XX, dic r(15)(p11.2q26.3; p11.2q26.3)[4]. SNP-array revealed that she has carried an de novo deletion at 15q26.3 (98 957 555-102 429 040) spanning approximately 3.4 Mb, which encompassed the n IGF1R gene. qPCR has confirmed haploinsufficiency of exons 3, 10 and 20 of the n IGF1R gene. Both of her parents had a normal karyotype.n Conclusion:The abnormal phenotype of the proband may be attributed to the microdeletion at 15q26.3, in particular haploinsuffiency of the n IGF1R gene and instability of the ring chromosome. Cytogenetic method combined with SNP-array and qPCR can efficiently delineate chromosomal aberrations and provide accurate information for clinical diagnosis and genetic counseling.n