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目的:探讨1例由KMT2D基因嵌合移码变异所致的Kabuki综合征1型患儿的基因型与表型的对应关系。方法:采用全外显子测序对家系进行检测，并应用Sanger测序对可疑变异位点进行验证。结果:先证者为3岁2个月的女性患儿，表现为特殊面容、认知障碍、轻度发育迟缓、皮纹异常、轻度骨骼异常、室间隔缺损、自闭症等。家系全外显子测序发现患儿KMT2D基因发生了新发嵌合移码变异(NM_003482.3)c.13058delG (p.Pro4353Argfs*31)(GRCh37/hg19)，嵌合比例约为21%。该变异在既往文献和数据库中未见报道，为新变异。Sanger测序进一步证实了该变异。此外染色体微阵列未检测到致病或可能致病性拷贝数变异。通过与既往报道的Kabuki综合征1型临床表型进行比较，发现患儿行为异常如自闭症、焦虑和睡眠障碍等表型罕有报道。结论:本例嵌合新变异的检出扩展了KMT2D基因变异谱，也丰富了Kabuki综合征1型临床表型谱，为其家系的遗传咨询提供了依据。“,”Objective:To explore the genotype-phenotype correlation in a child with Kabuki syndrome type 1 (KS1) caused by a mosaic frameshift variant of KMT2D gene.Methods:Trio-based whole-exome sequencing (WES) was carried for the patient and her parents.Candidate variant was verified by Sanger sequencing.Results:The proband, a 3-year-and-2-month-old Chinese girl, presented with distinctive facial features, cognitive impairment, mild developmental delay, dermatoglyphic abnormalities, minor skeletal anomalies, ventricular septal defect, and autistic behavior. Trio-based WES revealed that the proband has carried a n de novo mosaic frameshit variant of the KMT2D gene, namely NM_003482.3: c.13058delG (p.Pro4353Argfs*31)(GRCh37/hg19), for which the mosaicism rate was close to 21%. The variant was unreported previously and was confirmed by Sanger sequencing. Chromosomal microarray analysis (CMA) has revealed no pathogenic or likely pathogenic copy number variants. Compared with previously reported cases, our patient has presented obvious behavior anomalies including autism, anxiety and sleep problems, which were rarely reported.n Conclusion:This study has expanded the spectrum of KMT2D gene variants, enriched the clinical phenotypes of KS1, and facilitated genetic counseling for the family.