Table 1.

Genetics and frequency of extrarenal associations in NPHP

ParameterNPHP Type
123456
Mutated geneNPHP1NPHP2NPHP3NPHP4NPHP5NPHP6AHI1
Encoded proteinNephrocystin-1Nephrocystin-2Nephrocystin-3Nephrocystin-4Nephrocystin-5Nephrocystin-6Jouberin
Frequency of gene mutation (%)b2011221<2
Kidney cysts (%)100100100100100100?
Retinal degeneration (%)710≈4015100100?
Cerebellar vermis aplasia (%)≈1≈90100
Oculomotor apraxia (Cogan) (%)1<1?
  • aNPHP, nephronophthisis.

  • b Percentage of 976 patients from different families with NPHP-associated disorders as evaluated in the authors’ worldwide cohort. Different frequencies have been reported by Saunier et al. (157).