At present, causative mutations in 13 genes have been associated with JSRD (JBTS1/INPP5E, JBTS2/TMEM216, JBTS3/AHI1, JBTS4/NPHP1, JBTS5/CEP290, JBTS6/TMEM67, JBTS7/RPGRIP1L, JBTS8/ARL13B, JBTS9/CC2D2A, JBTS10/OFD1, JBTS12/KIF7, JBTS13/TCTN1 and the TCTN2 gene) [4,10-12]. Here, INPP5E is linked to Joubert syndrome and related disorders.