Mutations in COL1A1 of type I collagen genes in Chinese patients with osteogenesis imperfecta.

BACKGROUND

Osteogenesis imperfecta (OI) is an inherited bone disease caused by mutations in collagen genes. Because these mutations occur at a wide variety of sites in the genes and differ among populations, we studied the COL1A1 gene in Chinese with OI and compared the results with findings form other populations.

METHODS

COL1A1 gene mutations were detected by polymerase chain reaction and sequencing from 3 unrelated families and 1 sporadic case in Chinese.

RESULTS

Four COL1A1 mutations that were novel were found. The patients' clinical characteristics were variable, even within the same family. Notably, some of the novel COL1A1 variants were at the same nucleotide positions as previously described but with different nucleotide changes. In addition, we also found 1 patient with OI with 2 mutations in the same haplotypes.

CONCLUSIONS

We discuss the differences in phenotype related to the specific mutation sites. Although there have been many reports on mutations of COL1A1 and COL1A2, few cases have been reported in Chinese. Our data showed that the COL1A1 gene mutation might also play an important role in OI among Chinese. The Han Chinese represent a quarter of the world's population, and we believe that our new data contributes to fill in the type I collagen mutation map. We thought that the patient with OI could have 2 mutations in the same haplotypes, without limit to 1 mutation.