Joubert Syndrome (JS) is a phenotypically and genetically heterogeneous autosomal disorder. Major clinical manifestations include hypotonia, developmental delay, abnormal eye movements, and breathing abnormalities, which are caused by a complex of hindbrain malformations. These malformations lead to the “molar tooth sign” on MRI of the brain, which is the hallmark clinical feature of JS. Other organs that are variably involved in JS include retina, digits, liver, and kidney. It is an autosomal recessive disorder caused by mutations in the TMEM216 gene. It occurs more frequently in the Ashkenazi Jewish population, where the carrier rate is 1 in 92.  Recently, a founder mutation within the Ashkenazi Jewish population was identified in the TMEM216 gene as a new cause of JS. Ashkenazi Jewish individuals with a negative family history who test negative for the p.R12L mutation in TMEM216 have a revised carrier risk of 1 in 9,100.