[show abstract][hide abstract] ABSTRACT: Alagille Syndrome (OMIM 118450) is a multisystem developmental disorder inherited in an autosomal dominant pattern with variable expression. It commonly manifests in children with early cholestatic jaundice due to paucity of interlobular biliary ducts. Renal involvement is less common but can take various forms including renovascular disease, renal agenesis or hypoplasia, cystic renal disease, mesangiolipidosis, tubulointerstitial nephritis and renal tubular acidosis. We describe a family of Alagille syndrome with JAG 1 mutation running through at least two generations, affecting four members with variable phenotypic expressions and disease severity. Alagille syndrome should be considered in the differential diagnosis of adults with renovascular disease and children with agenesis/dysgenesis of kidney and reflux nephropathy even in the absence of hepatic disease. Renal transplant can be successful in these patients although living related donation may not be appropriate given the high penetrance and variable expression of this condition. This syndrome may cause symptomatic bradyarrhythmias as described in our series.