Objectives: Determine the model of inheritance of non-syndromic cleft palate in humans.
Design: Complex segregation analysis performed in families of consecutive newborns affected with non-syndromic cleft palate.
Setting and sample population: The Latin American Collaborative Study of Congenital Malformations (ECLAMC). Four hundred and seven consecutive newborns affected with non-syndromic cleft palate registered during the period 1967-97.
Outcome measure: Likelihood ratio test and Akaike information criterion (AIC) values.
Results: The single major locus recessive model provided a significantly better explanation of the data. It was the most parsimonious and had the smallest AIC value of the six models tested with approximately the same likelihood as the general model (chi2 = 2.44, p = 0.5).
Conclusions: To have defined a genetic model for non-syndromic cleft palate and provided evidence for a single major locus inheritance suggests that genetic linkage studies could be implemented.