目的 表皮松解性痣（EN）是表皮松解性角化过度型鱼鳞病（EI）镶嵌型的表型，该研究报道了1例由KRT10基因嵌合突变导致的罕见EN，并探讨该病基因型和表型。方法 收集1例于2024年11月在皮肤病诊治中心就诊的EN患儿的临床资料。分别采集患儿及其父母外周静脉血样本，同时获取患儿皮损处皮肤组织标本提取全基因组DNA，采用二代测序检测先证者及其父母的基因变异，并进行Sanger测序验证。同时提取100名无血缘关系的健康个体外周血基因组DNA，作为对照样本。结果 患儿，女，1岁7月龄，因“躯干、四肢条索状红斑1年余”在皮肤病诊治中心就诊。基因检测结果提示，患儿皮损组织中具有KRT10基因c.466C>T：p.Arg156Cys杂合变异（变异比例为10.18%），而血液中患儿及其父母均无该变异，提示其为新发的嵌合变异；美国医学遗传学与基因组学学会（ACMG）指南提示该位点突变为致病性变异。100名健康对照者均未见相同变异。结论 本研究明确KRT10基因c.466C>T:p.Arg156Cys为该例EN的致病性变异，其通过影响蛋白构象、破坏角蛋白中间丝组装与稳定性致病；患儿皮损病变组织呈低比例杂合变异、外周血为野生型，提示该变异为胚胎发育后期体细胞嵌合变异，多系统受累风险低，但需警惕生殖腺嵌合可能。

Objective Epidermolytic nevus (EN) is a mosaic phenotype of epidermolytic ichthyosis (EI). This study reported a rare case of EN caused by mosaic mutation of KRT10 gene, and explored the genotype and phenotype of this disease. Methods Clinical data of a child with EN who was admitted to the Dermatology Diagnosis and Treatment Center in November 2024 were collected. Peripheral venous blood samples of the child and her parents were collected respectively, and skin tissue samples from the child's lesional site were obtained to extract whole-genome DNA. Next-generation sequencing was used to detect gene variations in the proband and her parents, which was verified by Sanger sequencing. Meanwhile, peripheral blood genomic DNA of 100 unrelated healthy individuals was extracted as control samples. Results The child, a 1-year-and-7-month-old female, was admitted to the Dermatology Diagnosis and Treatment Center due to "striate erythema on the trunk and limbs for more than 1 year". Genetic testing results showed that the child had a heterozygous variation of KRT10 gene c.466C>T: p.Arg156Cys in the lesional tissue (variation ratio 10.18%), while the child and her parents had no such variation in the blood, suggesting it was a de novo mosaic mutation; the guidelines of the American College of Medical Genetics and Genomics (ACMG) indicated that this locus mutation was pathogenic. No identical variation was found in 100 healthy controls. Conclusions This study confirms that KRT10 gene c.466C>T (p.Arg156Cys) is the pathogenic mutation of this case of EN, which causes the disease by affecting protein conformation and disrupting the assembly and stability of keratin intermediate filaments; the low proportion of heterozygous mutation in the child's lesional tissue and wild type in the peripheral blood suggest that the mutation is a somatic mosaic variation occurring in the late stage of embryonic development, with a low risk of multi-system involvement, but the possibility of germline mosaicismshould be vigilant.