These findings suggest the possible role of FOXD3 haploinsufficiency in the pathogenesis of the craniosynostosis and MA of our patient but, as this is not supported by other case reports of patients with FOXD3 deletions, we can hypothesise the reduced penetrance of a single gene defect (clinical variability is very frequent when a transcription factor is involved in the pathogenesis of human diseases) [33], or a polygenic or multifactorial origin of the vascular defects. Here, FOXD3 is linked to microtia.