OTX2 and microtia: 2014). This gene accounts for approximately 3% of bilateral MA, with de novo heterozygous loss‐of‐function mutations being the most common cause (Wyatt et al. 2008). However, several cases of incomplete penetrance have been previously described, and it is estimated that up to 35% of OTX2 patients inherit the mutation from a carrier parent without the condition (Ragge et al. 2005a; Schilter et al. 2011; Gerth‐Kahlert et al. 2013).