Nephronophthisis and ulcerative colitis in siblings: a new association.

Nephronophthisis (NPH) is a chronic tubulointerstitial nephritis leading to terminal renal insufficiency. The disease is heterogeneous, but usually the inheritance pattern is autosomal recessive. In 80% of cases, the disease is caused by a homozygous deletion in NPHP1 gene in chromosome 2q13. Ulcerative colitis is an inflammatory bowel disease with chronic diarrhea, rectal bleeding and characteristic histological findings. Its etiology is suggested to be multifactorial, consisting of genetic susceptibility and unknown exogenous factors. We present two siblings with NPH and ulcerative colitis. As NPH in this family is not linked to 2q13, this association may represent a new, syndromic form of NPH.