[Application of log-linear model in the case-parent triad study].

We were introducing a log-linear model for case-parent triad study. Data from a previous study of the association between MTHFR C677T and cleft lip with or without cleft palate (CL/P) was analyzed, in order to investigate the maternal effect, fetal effect and their interaction, using a series of log-linear models. Our results showed that mothers who were carrying two copies of MTHFR C677T variant alleles appeared to have reduced the risk of CL/P in offspring, comparing to those with homozygous of wild-type allele. With S2=0.43 (95%CI: 0.19-0.95). No significant association was found for fetal genotype and maternal-fetal interaction with CL/P. Log-linear model method seemed to be useful in the estimation of maternal effect, fetal effect and maternal-fetal interaction, in the case-parent triad study design. This approach showed specific benefit in studies that related to genetic effects on complex diseases such as pregnancy complications and diseases originated from fetus.