A familial clustering of autoimmune and monogenic diabetes

Abstract

Background: Monogenic diabetes type 5 or Renal Cysts And Diabetes (RCAD) is a familial syndrome associated with renal disease and diabetes, caused by mutations in the HNF-1B gene. Early recognition is important to plan appropriate treatment and specialist input. Clinical case: We report the overlapping occurrence of type 1 diabetes and renal disease among different members of the same family. The aetiology of diabetes was autoimmune with strong antibody positivity, whilst the renal disease was caused by a mutation in the hepatocyte nuclear factor (HNF-1B) gene. Conclusions: A low threshold of clinical suspicion is important to recognise monogenic forms of diabetes at an early stage. Mild renal impairment is usually asymptomatic in the initial phases and, as such, this mutation is likely to be underdiagnosed. An uncertain aetiology with multiple family members being affected at an early age should prompt the clinician to pursue further investigations.