Genetic analysis of a child with 18q Deletion Syndrome and Developmental Dysplasia of Hip

Objective: To analyze genotypes and phenotypes of a child with Developmental Dysplasia of Hip (DDH), developmental delays, recurrent fever, hypothyroidism and cleft palate. Methods: G-banding karyotypeing analysis and Next-generation Sequencing(NGS) were performed on the child. The parents of the child were verified by copy number variations (CNV) and Sanger sequencing to determine the source of variations. Results: The karyotype of the child was 46, XX. A 10.44Mb deletion(chr18:67562936-78005270del) at 18q22.2q23 was found by NGS, as well as HSPG2 variation (chr1: 22206699, c.2244c > A, exon 17, p.h748q; chr1: 22157321–22157321, c.11671 + 154insA, Intron) originated from father and mother, respectively. Conclusion: This is the first 18q deletion syndrome case which accompanied by DDH. Most phenotypes of the child ,such as developmental delays, cleft palate, may be related to 18q22 2q23 deletion, while no variant genes related to DDH were found in this deletion region. DDH may be related to mutation of HSPG2.