RPGRIP1L and Ataxia: For example, mutations in RPGRIP1L (NPHP8/MKS5) can cause an NPHP phenotype, but also Meckel-Grüber syndrome (MKS), a pre- or perinatal lethal condition due to neural tube closure and heart defects, or Joubert syndrome (JBTS) that has cystic kidneys, mental retardation, cerebellar hypoplasia, ataxia, and developmental abnormalities [5, 6].