PolyA disorders include the following diseases: cleidocranial dysplasia (CCD), holoprosencephaly type 5 (HPE5), oculopharyngeal muscular dystrophy (OPMD), ARX mutation-associated syndromes, blepharophimosis-ptosis-epicanthus inversus syndactyly, mental retardation with growth hormone deficiency, congenital central hypoventilation (Haddad syndrome), hand–foot–genital syndrome, and synpolydactyly [72]. The gene discussed is ARX; the disease is Down syndrome.