More recently, a new family has been identified with a homozygous frameshift mutation in OGR1, resulting in a truncated OGR1 protein, and again only amelogenesis imperfecta is reported [76], and a whole genome sequencing study investigating natural human kos identified an individual who was homozygous for the already reported nonsense variant NM_003485.3:c.1006G > T of OGR1 [82]. Here, GPR68 is linked to amelogenesis imperfecta.