Abstract：
OBJECTIVE: To explore the genetic etiology of a child featuring global developmental and mental retardation.
METHODS: Chromosome G-banding karyotype analysis, copy number variation sequencing (CNV-seq) and high-resolution chromosome banding were used to screen the genomic variant in the child and his parents.
RESULTS: Both the child and his father were found to have a karyotype of 46,XY,del(18)(q21.1q21.3), whilst his mother was 46,XX. CNV-seq analysis showed that the child was arr[19]18q21.2-q21.32(chr18:48 422 190-58 039 582)×1, with a 10.58 Mb deletion which encompassed the TCF4 gene. The same deletion was found in neither parent. High-resolution banding revealed that the father has a fragment of 18q21.1q21.3 inserted into 5p13.1.
CONCLUSIONS: The child was diagnosed with Pitt-Hopkins syndrome due to the 18q21.2q21.32 deletion. Chromosome karyotyping and CNV-seq can effectively identify submicroscopic chromosome anomalies.
METHODS: Chromosome G-banding karyotype analysis, copy number variation sequencing (CNV-seq) and high-resolution chromosome banding were used to screen the genomic variant in the child and his parents.
RESULTS: Both the child and his father were found to have a karyotype of 46,XY,del(18)(q21.1q21.3), whilst his mother was 46,XX. CNV-seq analysis showed that the child was arr[19]18q21.2-q21.32(chr18:48 422 190-58 039 582)×1, with a 10.58 Mb deletion which encompassed the TCF4 gene. The same deletion was found in neither parent. High-resolution banding revealed that the father has a fragment of 18q21.1q21.3 inserted into 5p13.1.
CONCLUSIONS: The child was diagnosed with Pitt-Hopkins syndrome due to the 18q21.2q21.32 deletion. Chromosome karyotyping and CNV-seq can effectively identify submicroscopic chromosome anomalies.
摘要：
目的：探讨儿童整体发育和智力低下的遗传病因。
方法：染色体G显带核型分析，使用拷贝数变异测序(CNV-seq)和高分辨率染色体条带法筛选儿童及其父母的基因组变异.
结果：发现孩子和他的父亲的核型均为46，XY，德尔（18）（q21.1q21.3），而他的母亲是46，XX。CNV-seq分析表明，该孩子为arr[19]18q21.2-q21.32（chr18：48422190-58039582）×1，缺失10.58Mb，包含TCF4基因。在两个父级中都没有发现相同的删除。高分辨率条带显示父亲在5p13.1中插入了18q21.3的片段。
结论：由于18q21.2q21.32缺失，该儿童被诊断为Pitt-Hopkins综合征。染色体核型分析和CNV-seq可以有效识别亚显微染色体异常。
方法：染色体G显带核型分析，使用拷贝数变异测序(CNV-seq)和高分辨率染色体条带法筛选儿童及其父母的基因组变异.
结果：发现孩子和他的父亲的核型均为46，XY，德尔（18）（q21.1q21.3），而他的母亲是46，XX。CNV-seq分析表明，该孩子为arr[19]18q21.2-q21.32（chr18：48422190-58039582）×1，缺失10.58Mb，包含TCF4基因。在两个父级中都没有发现相同的删除。高分辨率条带显示父亲在5p13.1中插入了18q21.3的片段。
结论：由于18q21.2q21.32缺失，该儿童被诊断为Pitt-Hopkins综合征。染色体核型分析和CNV-seq可以有效识别亚显微染色体异常。
