Fetal genetic risk of isolated cleft lip only versus isolated cleft lip and palate: a subphenotype analysis using two population-based studies of orofacial clefts in Scandinavia.

Background: Cleft lip only (CLO) and cleft lip and palate (CLP) are commonly regarded as variants of the same defect and traditionally combined to form the single group of cleft lip with or without cleft palate (CL/P) prior to analysis. However, recent data have suggested that at least a subgroup of isolated CLO may be etiologically distinct from isolated CLP.

Methods: To explore fetal genetic risk of isolated CLO separately from isolated CLP, we performed a sub-phenotype analysis using two population-based studies of clefts in Scandinavia.

Maternal genes and facial clefts in offspring: a comprehensive search for genetic associations in two population-based cleft studies from Scandinavia.

Background: Fetal conditions can in principle be affected by the mother's genotype working through the prenatal environment.

Methodology/principal Findings: Genotypes for 1536 SNPs in 357 cleft candidate genes were available from a previous analysis in which we focused on fetal gene effects. After data-cleaning, genotypes for 1315 SNPs in 334 autosomal genes were available for the current analysis of maternal gene effects.

Genetic determinants of facial clefting: analysis of 357 candidate genes using two national cleft studies from Scandinavia.

Background: Facial clefts are common birth defects with a strong genetic component. To identify fetal genetic risk factors for clefting, 1536 SNPs in 357 candidate genes were genotyped in two population-based samples from Scandinavia (Norway: 562 case-parent and 592 control-parent triads; Denmark: 235 case-parent triads).

Methodology/principal Findings: We used two complementary statistical methods, TRIMM and HAPLIN, to look for associations across these two national samples.