A phenotypically less severe ARS mutant (without tooth anomalies), PITX2 R84W, has a similar DNA binding specificity compared to wild-type PITX2 and transactivates the Dlx2 promoter.
Direct sequencing of FKHL7 detected a C67T mutation that segregated with the ARS phenotype in this family, but was not detected in over 80 control chromosomes.