The location of variants in the GLI3 gene is associated with different clinical manifestations: frameshift mutations in the middle third of the gene cause PHS, whereas those in the first or last third of the gene cause a distinct syndrome called Greig cephalopolysyndactyly syndrome (poly- or syndactyly, hypertelorism, macrocephaly), which is not associated with HH. This evidence concerns the gene GLI3 and Pallister-Hall syndrome.