Homozygous defects of HOXA3 actually seem to cause lethal cardiovascular dysfunctions, loss and malformations of throat cartilages and jaw bones, disorganization of the throat musculature, absent thymus and parathyroids, and thyroid hypoplasia [16,17], while heterozygous defects are associated to ectopic thymus and/or parathyroids [18] so haploinsufficiency of this gene has been suggested [5] as the cause of these anomalies. Here, HOXA3 is linked to thyroid gland disorder.