GLI2 mutations are mostly associated with mild midfacial abnormalities, hypopituitarism and polydactyly with genito urinary tract anomalies in some cases rather than patent holoprosencephaly, despite abnormal HH signalling [109], with holoprosencephaly reported in only a minority (about 2%) of patients [110], possibly due to deletion of genes adjacent to GLI2 [111]. This evidence concerns the gene GLI2 and holoprosencephaly.