Moreover, whereas Six1 <sup>-/-</sup> mice exhibited partial transformation of maxillary zygomatic bone into a mandibular condyle-like structure, Six1 <sup>-/-</sup>Six2 <sup>+/-</sup> mice exhibit significantly increased penetrance of the maxillary malformation.
We suggest SIX2 haploinsufficiency as a potential congenital factor could be attributed to developmental malformation of the middle ear ossicles and upper eyelid.
Here, we aimed at confirming the role and the prevalence of SIX2 mutations in a large cohort of 125 individuals with various congenital abnormalities of kidneys and urinary tract.