Abstract: Objective? To report clinical features and genetic analysis of two cases of 45, X/ 46, X, +mar male children. Methods? Two hospitalized children with short stature were analyzed. The medical history and clinical data were collected, and karyotype analysis of peripheral blood was performed. The second-generation sequencing of sexual development related genes was performed in case one, and the whole genome copy number variation sequencing was performed in case two. Relevant literature was reviewed. Results? Two male children, one was 10 years and 7 months old, and the other was 3 years and 1 month old. Physical examination showed short stature, and complicated with gonadal development delay. Case one also presented with varicocele and partial empty sella revealed by cranial MRI, the karyotype of peripheral blood was 45, X [ 31 ] / 46, X, +mar [ 69 ]. The secondgeneration sequencing showed that the copy number of SRY gene on the short arm of Y chromosome was repeated, and USP9Y gene at long arm was deleted. In case two, the karyotype of the peripheral blood was 45, X [ 5 ] / 46, X, +mar [ 75 ]. The whole genome copy number variation sequencing test showed that the karyotype of 46, XY, AZFb + AZFc region of Y chromosome was completely deleted. Conclusion? Children with short stature should be paid close attention to the morphology and function of their external genitalia. If necessary, karyotype analysis or genetic analysis should be performed to avoid misdiagnosis.

Key words: short stature;? chromosome karyotype analysis;? child