Furthermore, heterozygous loss-of-function variants of histone acetyltransferase KAT6B causes two different genetic disorders, Genitopatellar syndrome and SBBYSS syndrome (23), both of which are characterized by patellar hypoplasia, and a variety of growth phenotype that may include microcephaly and postnatal growth retardation, which has been proposed to be mediated by regulation of RUNX2 expression by KAT6B (24). The gene discussed is KAT6B; the disease is microcephaly.