Abstract:

[Abstract] Objective To investigate COL1A1gene mutation by PCR-high resolution melting (PCR-HRM) and an? alyze the correlation between genotype and clinical phenotype in a child (proband) with osteogenesis imperfecta (OI).Meth? ods The family history of OI pedigree along with the clinical data was collected. Blood samples from the proband and his family members, as well as 50normal controls, were collected. The mutation of COL1A1gene was screened using PCR HRM and validated by the gene sequence.Results The detection of PCR-HRM showed the abnormal result of COL1A1 17exon in proband with a lower melting temperature (Tm) value than that of normal controls by0.4℃. There were signifi? cant differences in the standardization melting curve and the different melting curve between the proband and the normal controls. The sequencing result was c.1138G>A, which meant that cDNA of1138base G mutation into A. The mutations transformed the amino acid glycine into a serine at amino acid380（P. Gly380Ser), which resulted in missense mutations. The proband’s father and grandmother had the same mutation of COL1A1gene. The mutation was not found in the proband’s mother and normal controls. There was no report for such mutation in Chinese population. Pedigree analysis showed the fami? ly genetic characteristics of autosomal dominant inheritance. The proband was clinically diagnosed as OI type Ⅳwith more severe clinical phenotype.Conclusion PCR-HRManalysis is a new effective method for genetic screening of OI. COL1A1 mutation of c.1138G>A is a newly discovered mutation in Chinese population. Gly replaced inαhelical domain may lead to a more severe clinical phenotype.

Key words: Osteogenesis imperfecta, COL1A1 gene, Gene mutation, Genetic diagnosis, High-resolution melting