HNF-1β mutation affects PKD2 and SOCS3 expression causing renal cysts and diabetes in MODY5 kindred.

BACKGROUND

Maturity onset diabetes of young (MODY) type 5 is a form of non-insulin-dependent diabetes mellitus associated with renal cysts. It is an autosomal dominant disorder caused by mutations in the gene encoding hepatocyte nuclear factor-1β (HNF-1β).

METHODS

We performed molecular screening of HNF-1β in a 13-year-old patient and his affected father, and analyzed polycystic kidney disease 2 (PKD2) gene and suppressor of cytokine signaling 3 (SOCS3) expression in lymphoblastoid cell lines and lymphocytes from both patients.

RESULTS

We found a novel HNF-1β frameshift mutation (c.C1304del) that results in a truncated protein (p.I434IfsX1). The genetic change is localized in the transactivated protein domain.

CONCLUSIONS

We demonstrated that this novel HNF-1β mutation strongly influences the expression of both PKD2, responsible for the formation of the renal cysts, and SOCS3, which is associated with early diabetes onset.