NARP syndrome is a maternally inherited mitochondrial disease caused most often by pathogenic MT-ATP6 variants. The syndrome is characterized by impaired oxidative phosphorylation with prominent neurologic and retinal vulnerability, classically manifesting with neuropathy, ataxia, and retinitis pigmentosa. Clinical severity varies with heteroplasmy and may overlap with Leigh syndrome.
Conditions with similar clinical presentations that must be differentiated from NARP syndrome:
This report is retrieval-only and is generated directly from Asta results.
search_papers_by_relevance with snippet_search.name: NARP syndrome
creation_date: '2026-04-13T04:00:00Z'
updated_date: '2026-04-13T23:45:00Z'
description: >-
NARP syndrome is a maternally inherited mitochondrial disease caused most
often by pathogenic MT-ATP6 variants. The syndrome is characterized by
impaired oxidative phosphorylation with prominent neurologic and retinal
vulnerability, classically manifesting with neuropathy, ataxia, and retinitis
pigmentosa. Clinical severity varies with heteroplasmy and may overlap with
Leigh syndrome.
category: Mendelian
parents:
- hereditary disease
- mitochondrial disease
disease_term:
preferred_term: NARP syndrome
term:
id: MONDO:0010794
label: NARP syndrome
pathophysiology:
- name: MT-ATP6 ATP synthase dysfunction
description: >-
Pathogenic MT-ATP6 variants impair the proton-translocating membrane sector
of mitochondrial ATP synthase.
genes:
- preferred_term: MT-ATP6
term:
id: hgnc:7414
label: MT-ATP6
biological_processes:
- preferred_term: proton motive force-driven ATP synthesis
modifier: ABNORMAL
term:
id: GO:0015986
label: proton motive force-driven ATP synthesis
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Pathogenic mutations in MT-ATP6 are associated with the Leigh syndrome, the syndrome of neuropathy, ataxia, and retinitis pigmentosa (NARP), as well as with non-classical phenotypes, while MT-ATP8 is less frequently mutated in patients with mitochondrial disease.
explanation: This directly supports MT-ATP6 dysfunction as the canonical initiating lesion in NARP-spectrum mitochondrial disease.
downstream:
- target: Reduced mitochondrial ATP production
description: Defective ATP synthase coupling decreases efficient ATP generation.
- name: Reduced mitochondrial ATP production
description: >-
Inefficient oxidative phosphorylation limits ATP availability in tissues
with high metabolic demand.
biological_processes:
- preferred_term: oxidative phosphorylation
modifier: ABNORMAL
term:
id: GO:0006119
label: oxidative phosphorylation
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
Furthermore, intracellular ATP concentration was lower in patient myoblasts indicating defective energy production.
explanation: Patient-derived myoblast data directly supports reduced ATP production downstream of MT-ATP6/8 dysfunction.
downstream:
- target: Neuroretinal energy failure
description: Neurons, peripheral nerves, and retinal cells are especially vulnerable.
- name: Neuroretinal energy failure
description: >-
Energy failure in the nervous system and retina drives the core neurologic
and ophthalmologic phenotype.
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We suggest that the m.8561C>G mutation in MT-ATP6/8 is pathogenic, leads biochemically to impaired assembly and decreased ATP production of complex V, and results clinically in a phenotype with the core features of cerebellar ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
explanation: This links impaired complex V energy production to the characteristic multisystem neurologic phenotype.
downstream:
- target: Cerebellar dysfunction
description: Cerebellar energy failure contributes to gait instability.
- target: Peripheral nerve dysfunction
description: Peripheral nerve energy failure produces sensory and motor neuropathy.
- target: Retinal degeneration
description: Retinal energy failure leads to pigmentary retinopathy and vision loss.
- name: Cerebellar dysfunction
description: >-
Energetic failure within cerebellar systems produces impaired coordination
and gait instability.
- name: Peripheral nerve dysfunction
description: >-
Mitochondrial failure in peripheral nerves contributes to sensory and motor
neuropathy.
- name: Retinal degeneration
description: >-
Retinal energetic vulnerability contributes to pigmentary retinopathy and
progressive visual dysfunction.
phenotypes:
- name: Ataxia
category: Neurologic
description: Progressive gait and coordination impairment is a core clinical feature.
phenotype_term:
preferred_term: Ataxia
term:
id: HP:0001251
label: Ataxia
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We investigated two adult siblings presenting with features of cerebellar ataxia, peripheral neuropathy, diabetes mellitus, sensorineural hearing impairment, and hypergonadotropic hypogonadism.
explanation: This directly documents ataxia in MT-ATP6/8-related NARP-spectrum disease.
- name: Peripheral neuropathy
category: Neurologic
description: Peripheral neuropathy contributes to sensory loss, weakness, and areflexia.
phenotype_term:
preferred_term: Peripheral neuropathy
term:
id: HP:0009830
label: Peripheral neuropathy
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We investigated two adult siblings presenting with features of cerebellar ataxia, peripheral neuropathy, diabetes mellitus, sensorineural hearing impairment, and hypergonadotropic hypogonadism.
explanation: This directly documents peripheral neuropathy as a core NARP-spectrum manifestation.
- name: Retinitis pigmentosa
category: Ophthalmologic
description: Pigmentary retinal degeneration causes progressive visual impairment.
phenotype_term:
preferred_term: Retinitis pigmentosa
term:
id: HP:0000510
label: Rod-cone dystrophy
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Pathogenic mutations in MT-ATP6 are associated with the Leigh syndrome, the syndrome of neuropathy, ataxia, and retinitis pigmentosa (NARP), as well as with non-classical phenotypes, while MT-ATP8 is less frequently mutated in patients with mitochondrial disease.
explanation: This directly names retinitis pigmentosa within the canonical NARP phenotype.
- name: Sensorineural hearing impairment
category: Otolaryngologic
description: Sensorineural hearing impairment is part of the broader MT-ATP6-associated neurologic phenotype.
phenotype_term:
preferred_term: Sensorineural hearing impairment
term:
id: HP:0000407
label: Sensorineural hearing impairment
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We investigated two adult siblings presenting with features of cerebellar ataxia, peripheral neuropathy, diabetes mellitus, sensorineural hearing impairment, and hypergonadotropic hypogonadism.
explanation: This directly documents sensorineural hearing impairment in an MT-ATP6/8 NARP-overlap phenotype.
- name: Diabetes mellitus
category: Endocrine
description: Diabetes mellitus can occur in NARP-spectrum mitochondrial disease with MT-ATP6/8 dysfunction.
phenotype_term:
preferred_term: Diabetes mellitus
term:
id: HP:0000819
label: Diabetes mellitus
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We investigated two adult siblings presenting with features of cerebellar ataxia, peripheral neuropathy, diabetes mellitus, sensorineural hearing impairment, and hypergonadotropic hypogonadism.
explanation: This directly documents diabetes mellitus in an MT-ATP6/8 NARP-overlap phenotype.
biochemical: []
genetic:
- name: MT-ATP6
gene_term:
preferred_term: MT-ATP6
term:
id: hgnc:7414
label: MT-ATP6
association: Causal pathogenic mitochondrial DNA variant with heteroplasmy-dependent severity
inheritance:
- name: Mitochondrial inheritance
inheritance_term:
preferred_term: Mitochondrial inheritance
term:
id: HP:0001427
label: Mitochondrial inheritance
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Mutation heteroplasmy correlated with the disease phenotype in five family members.
explanation: Maternal mitochondrial inheritance with heteroplasmy-dependent expression is directly supported by family-based genotype-phenotype correlation.
evidence:
- reference: PMID:27502083
reference_title: A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Pathogenic mutations in MT-ATP6 are associated with the Leigh syndrome, the syndrome of neuropathy, ataxia, and retinitis pigmentosa (NARP), as well as with non-classical phenotypes, while MT-ATP8 is less frequently mutated in patients with mitochondrial disease.
explanation: This directly supports MT-ATP6 as the established causal gene for NARP-spectrum disease.
environmental: []
treatments:
- name: Supportive mitochondrial disease management
treatment_term:
preferred_term: supportive care
term:
id: MAXO:0000950
label: supportive care
description: >-
Management is supportive and includes symptom-based neurologic,
ophthalmologic, and rehabilitation care.
target_phenotypes:
- preferred_term: Ataxia
term:
id: HP:0001251
label: Ataxia
- name: Physical therapy
treatment_term:
preferred_term: physical therapy
term:
id: MAXO:0000011
label: physical therapy
description: >-
Rehabilitation is used to preserve mobility, balance, and function in
progressive neuromuscular disease.
target_phenotypes:
- preferred_term: Ataxia
term:
id: HP:0001251
label: Ataxia
diagnosis:
- name: Mitochondrial DNA testing
diagnosis_term:
preferred_term: genetic testing
term:
id: MAXO:0000127
label: genetic testing
description: >-
Molecular diagnosis is established by identification of a pathogenic
MT-ATP6 variant and heteroplasmy assessment.
results: Pathogenic MT-ATP6 variant supports the diagnosis of NARP syndrome.
- name: Ophthalmologic evaluation
diagnosis_term:
preferred_term: clinical assessment
term:
id: MAXO:0000487
label: clinical assessment
description: >-
Retinal examination helps document pigmentary retinopathy and disease
severity.
results: Pigmentary retinopathy supports the syndromic diagnosis.
differential_diagnoses:
- name: Leigh syndrome
disease_term:
preferred_term: Leigh syndrome
term:
id: MONDO:0009723
label: Leigh syndrome
description: >-
Higher mutant heteroplasmy in MT-ATP6-related disease can produce Leigh
syndrome rather than the NARP phenotype.
- name: MELAS syndrome
disease_term:
preferred_term: MELAS syndrome
term:
id: MONDO:0010789
label: MELAS syndrome
description: >-
Other mitochondrial DNA disorders can overlap with neurologic impairment and
ophthalmologic findings.
clinical_trials: []
datasets: []