PKD2 and normal pressure hydrocephalus: Interestingly, NEK8/NPHP9 was shown to positively regulate polycystin-2 expression and ciliary localization (Smith L. A. et al., 2006; Sohara et al., 2008; Manning et al., 2013), in agreement with the cystic kidneys observed in infantile NPH linked to mutations in InvsC genes.