[A case of Congenital disorder of glycosylation due to SSR4 gene deletion].

To explore the clinical and molecular characteristics of a child with Congenital disorders of glycosylation (CDG). A 4-month-old boy who had presented at the Children's Hospital Affiliated to Zhejiang University Medical School on December 31, 2019 due to feeding difficulties after birth was selected as the study subject. High-throughput sequencing was carried out for the patient, and real-time qPCR was used for validating the suspected deletion fragments and the carrier status of other members of his family. High-throughput sequencing revealed that the child had lost the capture signal for chrX: 153 045 645-153 095 809 (approximately 50 kb), which has involved 4 OMIM genes including SRPK3, IDH3G, SSR4 and PDZD4. qPCR verified that the copy number in this region was zero, while that of his elder brother and parents was all normal. The deletion of the fragment containing the SSR4 gene in the Xq28 region probably underlay the SSR4-CDG in this child.