- A gene for familial juvenile nephronophthisis (recessive medullary cystic kidney disease) maps to chromosome 2p. Antignac, C., Arduy, C.H., Beckmann, J.S., Benessy, F., Gros, F., Medhioub, M., Hildebrandt, F., Dufier, J.L., Kleinknecht, C., Broyer, M. Nat. Genet. (1993)