MICA Gene Polymorphism Not Associated with Nonsyndromic Cleft Lip with or without Cleft Palate in the Japanese Population?

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is one of the most common birth defects. Despite its frequency, the etiology remains largely unknown. Most likely, both genetic and environmental factors contribute to this malformation. A polymorphic gene family, the major histocompatibility complex class I chain-related gene A (MICA), is located about 40 kb centromeric to the HLA-B gene. In this study, we analyzed the association between MICA gene polymorphisms and NSCLP in Japanese patients. Methods: The (GCT)n polymorphism of the MICA gene was investigated in 94 patients with NSCLP and 180 normal controls using polymerase chain reaction amplification and denaturing polyacrylamide gel electrophoresis. Results: Our results demonstrate that there are no differences in microsatellite allele frequency between NSCLP patients and controls. However, the microsatellite allele frequency of the MICA-A6 (p = 0.045) allele was increased in male patients, as compared with controls. Further, the MICA-A5 (p = 0.359) allele was also increased in female NSCLP patients. Conclusion: These results suggest that the microsatellite allele frequencies of the MICA-A6 allele increased in male NSCLP patients. Although the MICA-A5 allele increased in female NSCLP patients, the increase was not statistically significant. These results suggest that the MICA gene could be one of the candidate genes for NSCLP.