BACKGROUND: Spondyloepiphyseal dysplasia congenita is an autosomal dominant cartilaginous dysplasia characterized by short trunk, abnormal epiphysis, and flattened vertebral body. Skeletal features of SEDC are present at birth and evolve over time. Other features of SEDC include myopia and/or retinal degeneration with retinal detachment and cleft palate. A mutation in the COL2A1 gene located in 12q13.11 is considered as one of the important causes of SEDC. In 2016, Barat-Houari et al. reported a large number of COL2A1 mutations. Among them, a non-synonymous mutation in COL2A1 exon 37, c.2437G>A (p. Gly813Arg), has been reported to cause SEDC in only one patient from France so far.
METHODS: We followed up a patient with SEDC phenotype and his family members. The clinical manifestations, physical examination and imaging examination, including X-ray, CT and MRI, were recorded. The whole-exome sequencing was used to detect the patients\' genes, and the pathogenic genes were screened out by comparing with many databases.
RESULTS: We report a Chinese patient with SEDC phenotype characterized by short trunk, abnormal epiphysis, flattened vertebral body, narrow intervertebral space, dysplasia of the odontoid process, chicken chest, scoliosis, hip and knee dysplasia, and joint hypertrophy. Gene sequencing analysis showed that the patient had a heterozygous mutation (c.2437G>A; p. Gly813Arg) in the COL2A1 gene. No COL2A1 mutation or SEDC phenotype was observed in his family members. This is the first report of SEDC caused by this mutation in an East Asian family.
CONCLUSIONS: This report provides typical clinical, imaging, and genetic evidence for SEDC, confirming that a de novo mutation in the COL2A1 gene, c.2437G>A (p. Gly813Arg), causes SEDC in Chinese population.

To present three identified novel COL2A1 mutations causing spondyloepiphyseal dysplasia congenita (SEDC) in three unrelated Chinese families, and perform analysis regarding the clinical and genetic features of SEDC in the Chinese population through assessment of the literature.
Medical history, physical examination, radiographic and laboratory tests were obtained from three Chinese clinically diagnosed SEDC patients. PCR technique and direct nucleotide sequencing were conducted to identify mutations in the COL2A1 gene. The protein functions of all the missense mutations were predicted by SIFT and Polyphen-2. Contrast analysis of Chinese SEDC cases were performed through the literature retrieval of the HGMD BIOBASE and PubMed database.
Three novel heterozygous missense mutations (Gly537Asp, Gly909Ser, and Gly1149Val) in the COL2A1 gene were detected in this study. Literature review discovered a total of 15 COL2A1 mutations in Chinese SEDC patients. We analyzed the clinical features, mutation characteristics and explored the genotype-phenotype correlation of these Chinese SEDC cases.
Our study contributed to the further expansion of the COL2A1 mutation spectrum and provided more information concerning SEDC in the Chinese population through literature review.