Dissecting the genetic influence of the orofacial complex

Abstract

Disorders of the orofacial complex are among the most common congenital defects. Studies of these disorders have been confounded by a high level of genetic heterogeneity with single gene defects producing a variety of dysmorphisms or, conversely, by a variety of gene defects independently producing a similar phenotype. The identification of normal phenotypic variation, and their genetic basis, is critical to understanding the epidemiology of craniofacial anomalies.To identify the genetic architecture influencing normal orofacial variation, we examined 15 quantitative traits describing the form of the upper and lower arcades taken from whole mouth dental casts of 447 healthy participants in the Jiri Dental Study from eastern Nepal. A variance components‐based linkage analysis method (SOLAR) was used to obtain estimates of heritability and multipoint LOD scores. All traits are significantly heritable with between 18% and 55% of the variation attributable to genetic factors. A measure of palate length (urmh) has an unambiguous significant linkage to chromosome 17 with a LOD score of 3.11. Interesting signals above 2 were found for seven other traits. Supported by DE018497, NIDCR.