Intraflagellar transport 172 (IFT172) is a newly identified member of IFT proteins closely involved in some rare ciliopathies such as Mainzer-Saldino syndrome (MZSDS) and BBS, though the underpinning causal mechanisms remain largely elusive. The gene discussed is IFT172; the disease is short-rib thoracic dysplasia 9 with or without polydactyly.