TMEM67 and Meckel syndrome, type 1: However, mutations in the TMEM67/MKS3 gene are the most common cause of MKS, accounting for over 15% of all MKS cases in unselected cohorts (Khaddour et al., 2007; Consugar et al., 2007; Szymanska et al., 2012), with mutations in TMEM67 associated frequently with a diagnosis of malformation of the ductal plate in the liver (Khaddour et al., 2007; Consugar et al., 2007; Szymanska et al., 2012).