Although intra-familial variability in ADPKD is much lower than inter-familial variability and some genotype-phenotype correlations have been reported in the development of ICAs in ADPKD patients, the finding that not all ADPKD individuals of high-risk families develop ICAs indicates that other genetic variants may be involved besides the PKD1 or PKD2 mutations14, 15, 45. The gene discussed is PKD2; the disease is familial isolated congenital asplenia.