Characteristics of MSX1 gene in Korean nonsyndromic cleft lip and palate individuals

Objective: This study was performed to identify the characteristics of the MSX1 gene (locus chromosome 4p16) in Korean nonsyndromic cleft lip and palate (CUP), which is assumed to be a major candidate gene acting as a causal factor in nonsyndromic CUP and missing teeth. Methods: The 36 individuals (23 males and 13 females) who had visited the department of orthodontics at from 1998 to 2002 and who had nonsyndromic CUP were included in the study. Using a PCR-based assay, the MSX1 gene was amplified, sequenced, and searched for inferred protein products (Reference: Homo sapiens MSX1, accession number AF426432 and NP_002439). The common single nucleotide polymorphisms were observed. Results: In exon 1, nucleotide "A" of the 253 basepair (bp) region was substituted for "G", and in the 255 bp region, nucleotide "G" was inserted. In exon 2, nucleoticle "C" of the 11 bp region was substituted for "A", and "T" or "G" was inserted into the 351 bp region whereas "T" or "A" was inserted into the 352 bp region. In protein analysis, "Thr85Ala" missense mutation was found. The "Thr85Ala" missense mutation in this study is different from those of studies using subjects of other races. Conclusions: The results suggest that there is specific mutation of MSX1 in Korean and it plays an important role in Korean nonsyndromic CUP. However, any distinct genetic polymorphisms between CUP with missing teeth in the cleft region and CUP without missing teeth could not be found.