Department of Endocrinology, Affiliated Children's Hospital of Capital Institute of Pediatrics, No.2, Yabao Road, Chaoyang District, Beijing, 100020, China.
Department of Medical Genetics, Capital Institute of Pediatrics, Room 616, No.2, Yabao Road, Chaoyang District, Beijing, 100020, China.
BMC Pediatr. 2023 Mar 4;23(1):104. doi: 10.1186/s12887-023-03872-y.
Isodicentric Y chromosome (idic(Y)) is the most commonly reported aberration of the human Y chromosome, which is an important cause of abnormal sexual development. The breakpoints of isodicentric Y chromosome mostly occurred in Yq11.2 and Yp11.3, however, the breakpoints in Yq12 are relatively rare.
We described a 10-year-old boy presenting hypospadias, micropenis and short stature, as well as unilateral cryptorchidism without normal testicular seminiferous tubules structure by biopsy. Whole exome sequencing didn't find any pathogenic/likely pathogenic variants related to phenotypes of this patient. Copy number variation sequencing showed the duplication of whole Y chromosome. Subsequently, karyotyping and FISH analyses demonstrated his genetic diagnosis was mosaic 45,X[8]/46,X,psu idic(Y)(q12)[32], with the breakpoint in Yq12.
Our case proved that it would be beneficial to integrate high-throughput sequencing with cytogenetic technique for precise diagnosis, treatment and genetic counselling.
等臂染色体 Y（idic(Y)）是人类 Y 染色体最常见的异常，是导致性发育异常的重要原因。等臂染色体 Y 的断裂点大多发生在 Yq11.2 和 Yp11.3，但 Yq12 中的断裂点相对较少。
我们描述了一名 10 岁男孩，表现为尿道下裂、小阴茎和身材矮小，单侧隐睾，活检未见正常睾丸生精小管结构。全外显子组测序未发现任何与该患者表型相关的致病性/可能致病性变异。拷贝数变异测序显示整条 Y 染色体重复。随后，核型分析和 FISH 分析显示他的遗传诊断为嵌合体 45,X[8]/46,X,psu idic(Y)(q12)[32]，断裂点位于 Yq12。
本病例证明，将高通量测序与细胞遗传学技术相结合，对于精确诊断、治疗和遗传咨询是有益的。
