Disease Directory NARP Syndrome
Mitochondrial

NARP Syndrome

Also known as: neurogenic weakness ataxia retinitis pigmentosa, MT-ATP6 T8993G

Prevalence

Rare; exact prevalence unknown, fewer than 1 in 500,000 estimated

Onset

Childhood to early adulthood

Type

Rare mitochondrial disease

Gene

MT-ATP6 (mtDNA)

About NARP Syndrome

NARP syndrome is a maternally inherited mitochondrial disorder caused by pathogenic variants, most commonly m.8993T>G or m.8993T>C, in the MT-ATP6 gene encoding subunit 6 of mitochondrial ATP synthase. Clinical features include neurogenic muscle weakness, ataxia, and retinitis pigmentosa, and the severity of the phenotype correlates with the level of heteroplasmy. High heteroplasmy levels (above ~90%) typically result in the more severe Leigh syndrome phenotype, while lower levels produce the NARP phenotype.

Common Clinical Features

Retinitis pigmentosa and visual deterioration Cerebellar ataxia Neurogenic muscle weakness Sensory neuropathy Seizures Cognitive impairment Sensorineural hearing loss

Clinical Trial Eligibility Tips

What to know before applying to NARP Syndrome trials.

Heteroplasmy level at m.8993 directly correlates with disease severity and is a critical eligibility variable; request quantitative next-generation sequencing in blood and if possible urine.

Ophthalmological assessment confirming retinitis pigmentosa is often required for enrolment; ensure a recent ERG and fundus examination are documented.

NARP and Leigh syndrome share the same genetic locus; confirm phenotypic classification with your neurologist to ensure application to the appropriate trial.

Patient Resources

Patient Organization

United Mitochondrial Disease Foundation

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Natural History Registry

North American Mitochondrial Disease Consortium (NAMDC) Registry

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Orphanet

European reference resource for rare diseases (ORPHA:644)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

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Find recruiting NARP Syndrome trials

Search 500,000+ studies from ClinicalTrials.gov, filtered for NARP Syndrome. Updated daily.

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