CTNND1 encodes the catenin delta-1 (alias p120ctn), an Armadillo repeat protein that interacts closely with the E-cadherin. The intracellular domain of E-cadherin binds to p120ctn, stabilizing the E-cadherin complex at the membrane and preventing its degradation. The majority of the mutations identified in patients affected with Blepharocheilodontic (BCD) syndrome result in a premature stop codon (5/6). The sole missense variant identified in the condition, p.(Gly532Asp), is assumed to disrupt p120ctn/E-cadherin interactions.
Unlike BCD syndrome, mutations identified in isolated cleft lip/palate (CLP) mostly result in amino-acid substitutions (5/9). These mutations are also assumed to result in disruption of p120ctn/E-cadherin interactions.