Although we cannot rule out the possibility that abrogated MRDS1/OFCC1/Mrds1/Ofcc1 is insufficient to cause craniofacial abnormalities, the simplest explanation for the current observation is that MRDS1/OFCC1 is not a causal gene for orofacial cleft seen in subjects with a chromosomal break at 6p24. Here, OFCC1 is linked to orofacial cleft.