[Clinical and genetic characteristic in patients with disorders of sex development caused by Y chromosome copy number variant].

Objective: To investigate the clinical phenotype and genetic characteristics of disorders of sex development (DSD) caused by Y chromosome copy number variant (CNV). Methods: A retrospective analysis was performed on 3 patients diagnosed with DSD caused by Y chromosome CNV admitted to the First Affiliated Hospital of Zhengzhou University from January, 2018 to September, 2022. Clinical data were collected. Clinical study and genetic test were performed by karyotyping, whole exome sequencing (WES), low coverage whole genome copy number variant sequencing (CNV-seq), fluorescence in situ hybridization (FISH) and gonadal biopsy. Results: The 3 children, aged 12, 9, 9 years, the social gender were all female, presented with short stature, gonadal dysplasia and normal female external genital. No other phenotypic abnormality was found except for case 1 with scoliosis. The karyotype of all cases were identified as 46, XY. No pathogenic vraiants were found by WES. CNV-seq determined that case 1 was 47, XYY,+Y(2.12) and case 2 was 46, XY,+Y(1.6). FISH concluded that the long arm of Y chromosome was broken and recombined near Yq11.2, and then produced a pseudodicentric chromosome idic(Y). The karyotype was reinterpreted as mos 47, X, idic(Y)(q11.23)×2(10)/46, X, idic(Y)(q11.23)(50) in case 1. The karyotype was redefined as 45, XO(6)/46, X, idic(Y)(q11.22)(23)/46, X, del(Y)(q11.22)(1) in case 2. 46, XY, -Y(mos) was found by CNV-seq in case 3, and the karyotype of 45, XO/46, XY was speculated. Conclusions: The clinical manifestations of children with DSD caused by Y chromosome CNV are short stature and gonadal dysgenesis. If there is an increase of Y chromosome CNV detected by CNV-seq, FISH is recommended to classify the structural variation of Y chromosome.目的： 探讨Y染色体拷贝数变异致性发育异常（DSD）患儿的临床表型和遗传学特点。 方法： 回顾性分析郑州大学第一附属医院2018年1月至2022年9月收治的3例Y染色体拷贝数变异致DSD患儿的临床资料，应用染色体核型分析、全外显子测序（WES）、低深度全基因组拷贝数变异测序（CNV-seq），荧光原位杂交（FISH）和性腺组织病理活检技术对患儿进行临床分析和遗传学检测。 结果： 3例患儿就诊年龄分别为12、9、9岁，均表现为身材矮小和性腺发育不良，社会性别均为女。均为正常女童外阴，例1伴脊柱侧弯，余未见明显异常。3例患儿均报告为46，XY核型，WES未发现相关基因变异。CNV-seq确定例1为47，XYY，+Y（2.12），例2为46，XY，+Y（1.6），即Y染色体拷贝数增加。FISH最终确定2例患儿Yq11.2附近断裂后发生重组，为携带拟双着丝粒Y染色体idic（Y）的嵌合体DSD。例1核型重新诠释为mos 47，X，idic（Y）（q11.23）×2［10］/46，X，idic（Y）（q11.23）［50］，例2为45，XO［6］/46，X，idic（Y）（q11.22）［23］/46，X，del（Y）（q11.22）［1］。例3为46，XY，-Y（mos），即Y染色体拷贝数减少，可能为45，XO/46，XY嵌合体。 结论： Y染色体拷贝数变异致DSD的女童表现为身材矮小和性腺发育不良，CNV-seq检测到Y染色体拷贝数增加，可采用FISH明确Y染色体结构变异。.