HOXA1 and microtia: Microtia-affected piglets in our study manifest many symptoms that are present in humans with HOXA1 truncating mutations (Bosley et al., 2008, , 2007; Tischfield et al., 2005) or seen in Hoxa1-null mice (Chisaka et al., 1992; Lufkin et al., 1991), including abnormally shaped outer and middle ears, deafness, eyelid defects and, at least in affected humans, hypoventilation, swallowing dysfunction mainly due to cleft palate and mental retardation.