Mutations of the MKS1 gene contribute to approximately 7% of all reported MKS cases (Hartill et al., 2017), but only a few mutations in MKS1 have been reported to cause JBTS (Romani et al., 2014; Bachmann-Gagescu et al., 2015; Bader et al., 2016; Irfanullah et al., 2016; Vilboux et al., 2017). This evidence concerns the gene MKS1 and Joubert syndrome.