Bi-allelic REN Mutations and Undetectable Plasma Renin Activity in a Patient With Progressive CKD

Abstract

Renin is a component of the renin-angiotensin system and plays an important role in the regulation of embryonic kidney development, blood pressure, kidney perfusion, and potassium and acid-base balance. Identification and characterization of renin mutations provide unique insight into the physiology of renin and its organ-specific functionality and regulation. Total loss of renin production because of bi-allelic loss-of-function REN mutations results in autosomal recessive renal tubular dysgenesis and death within the first week of life. Heterozygous REN mutations affecting synthesis and leading to intracellular deposition of mutant renin result in autosomal dominant tubulointerstitial kidney disease, with an age of onset and clinical presentation dependent on protein domain-specific mutations. Here, we describe a patient with bi-allelic REN mutations and loss of systemic renin activity but functional kidney development. This case illustrates that bi-allelic mutations of REN and other renin-angiotensin system genes may present as slowly progressive chronic kidney disease (CKD). Clinical presentation of the patient provides additional insight into REN genetic disorders and renin function in embryonic kidney development.