Genetic analysis of two children with developmental delay and intellectual disability
王凤阳 1祁娜 1高越 1吴东 1张梦汀 1张倩 1杨科 1彭会娟 2雷星星 1廖世秀 1许芯
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作者信息
1. 1河南省人民医院 郑州大学人民医院 河南省医学遗传研究所，郑州 450003
2. 2河南省人民医院超声科，郑州 450003
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摘要
目的 明确2例发育迟缓/智力障碍(DD/ID)患儿的遗传学病因。 方法 选取分别于2021年8月29日以及2019年8月5日就诊于河南省人民医院的2例DD/ID患儿作为研究对象，收集患儿的临床资料，并应用微阵列比较基因组杂交技术(aCGH)对患儿及其父母的外周血样进行染色体拷贝数变异(CNV)分析。 结果 2例患儿分别为2岁10个月和3岁，均具有发育迟缓、智力障碍、头颅MRI异常等表现。aCGH检测患儿1结果为arr[hg19]6q14.2q15(84621837_90815662)×1，提示存在6.19 Mb缺失，所涉及的ZNF292基因的杂合变异可能导致常染色体显性智力发育障碍64。根据美国医学遗传学与基因组学学会(ACMG)相关指南评判为致病性CNV；患儿2的检测结果为arr[hg19]22q13.31q13.33(46294326_51178264)×1，提示存在4.88 Mb缺失，所涉及的SHANK3基因单倍剂量不足可能导致Phelan-McDermid综合征，评判为致病性CNV。2例患儿的父母检测结果均未见异常。 结论 染色体6q14.2q15缺失和22q13.31q13.33缺失可能分别是2例患儿发育迟缓和智力障碍的遗传学病因，ZNF292基因单倍剂量不足可能是导致6q14.2q15缺失患儿临床表型的关键因素。 Objective To explore the genetic etiology of two patients with developmental delay and intellectual disability. Methods Two children who were respectively admitted to Henan Provincial People′s Hospital on August 29, 2021 and August 5, 2019 were selected as the study subjects. Clinical data were collected, and array comparative genomic hybridization (aCGH) was carried out on the children and their parents for the detection of chromosomal microduplication/microdeletions. Results Patient 1 was a 2-year-and-10-month female and patient 2 was a 3-year-old female. Both children had featured developmental delay, intellectual disability, and abnormal findings on cranial MRI. aCGH revealed that patient 1 has harbored arr[hg19]6q14.2q15(84621837_90815662)×1, a 6.19 Mb deletion at 6q14.2q15, which encompassed ZNF292, the pathogenic gene for Autosomal dominant intellectual developmental disorder 64. Patient 2 has harbored arr[hg19] 22q13.31q13.33(46294326_51178264)×1, a 4.88 Mb deletion at 22q13.31q13.33 encompassing the SHANK3 gene, haploinsufficiency of which can lead to Phelan-McDermid syndrome. Both deletions were classified as pathogenic CNVs based on the guidelines of American College of Medical Genetics and Genomics (ACMG) and were not found in their parents. Conclusion The 6q14.2q15 deletion and 22q13.31q13.33 deletion probably underlay the developmental delay and intellectual disability in the two children, respectively. Haploinsufficiency of the ZNF292 gene may account for the key clinical features of the 6q14.2q15 deletion.
Abstract
Objective To explore the genetic etiology of two patients with developmental delay and intellectual disability. Methods Two children who were respectively admitted to Henan Provincial People′s Hospital on August 29, 2021 and August 5, 2019 were selected as the study subjects. Clinical data were collected, and array comparative genomic hybridization (aCGH) was carried out on the children and their parents for the detection of chromosomal microduplication/microdeletions. Results Patient 1 was a 2-year-and-10-month female and patient 2 was a 3-year-old female. Both children had featured developmental delay, intellectual disability, and abnormal findings on cranial MRI. aCGH revealed that patient 1 has harbored arr[hg19]6q14.2q15(84621837_90815662)×1, a 6.19 Mb deletion at 6q14.2q15, which encompassed ZNF292, the pathogenic gene for Autosomal dominant intellectual developmental disorder 64. Patient 2 has harbored arr[hg19] 22q13.31q13.33(46294326_51178264)×1, a 4.88 Mb deletion at 22q13.31q13.33 encompassing the SHANK3 gene, haploinsufficiency of which can lead to Phelan-McDermid syndrome. Both deletions were classified as pathogenic CNVs based on the guidelines of American College of Medical Genetics and Genomics (ACMG) and were not found in their parents. Conclusion The 6q14.2q15 deletion and 22q13.31q13.33 deletion probably underlay the developmental delay and intellectual disability in the two children, respectively. Haploinsufficiency of the ZNF292 gene may account for the key clinical features of the 6q14.2q15 deletion.
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