Renal Involvement in Neuropathy, Ataxia, Retinitis Pigmentosa (NARP) Syndrome: A Case Report

Am J Kidney Dis. 2018 May;71(5):754-757. doi: 10.1053/j.ajkd.2017.09.020. Epub 2017 Dec 8.


We report a case of a patient who had the mitochondrial cytopathy complex of neuropathy, ataxia, and retinitis pigmentosa (NARP) syndrome diagnosed at age 11 years with a biopsy-proven kidney involvement that progressed to end-stage renal disease at age 21 years. Mutations of mitochondrial DNA (mtDNA) are maternally inherited and lead to mitochondrial cytopathies with predominant neurologic manifestations: psychomotor retardation, epilepsy, ataxia, neuropathy, and myopathy. Given the ubiquitous nature of mitochondria, cellular dysfunction can also appear in tissues with high metabolic turnover; thus, there can be cardiac, digestive, ophthalmologic, and kidney complications. Mutations in the MT-ATP6 gene of mtDNA have been shown to cause NARP syndrome without renal involvement. We report a patient who had NARP syndrome diagnosed at age 11 years in whom glomerular proteinuria was present very early after diagnosis. Although neurologic manifestations were stable over time, he developed worsening proteinuria and kidney function. He started dialysis therapy at age 21 years. Kidney biopsy confirmed the mitochondrial cytopathy histologically, with abnormal mitochondria seen on electron microscopy. The MT-ATP6 gene mutation was detected in the kidney biopsy specimen.

Keywords: NARP (neuropathy, ataxia, and retinitis pigmentosa) syndrome; case report; dialysis; end-stage renal disease (ESRD); focal segmental glomerulosclerosis (FSGS); heteroplasmy; mitochondrial cytopathy; proteinuria; reduced kidney function; renal biopsy.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Ataxia / physiopathology
  • Biopsy, Needle
  • Child
  • Disease Progression
  • Follow-Up Studies
  • Genetic Predisposition to Disease*
  • Humans
  • Immunohistochemistry
  • Kearns-Sayre Syndrome / physiopathology
  • Kidney Diseases / pathology*
  • Kidney Diseases / physiopathology
  • Kidney Diseases / therapy*
  • Male
  • Mitochondrial Myopathies / diagnosis*
  • Mitochondrial Myopathies / genetics*
  • Mitochondrial Myopathies / physiopathology
  • Mitochondrial Myopathies / therapy
  • Mitochondrial Proton-Translocating ATPases / genetics*
  • Rare Diseases
  • Renal Dialysis
  • Retinitis Pigmentosa / diagnosis*
  • Retinitis Pigmentosa / genetics*
  • Retinitis Pigmentosa / physiopathology
  • Retinitis Pigmentosa / therapy
  • Treatment Outcome
  • Young Adult


  • MT-ATP6 protein, human
  • Mitochondrial Proton-Translocating ATPases

Supplementary concepts

  • Mitochondrial cytopathy
  • Neuropathy ataxia and retinitis pigmentosa