PET100-Related COX Deficiency

Mendelian MONDO:0033646 Pathograph 21 Show in embeddings browser Mitochondrial Disease Inborn Error of Metabolism

PET100-related COX deficiency (mitochondrial complex IV deficiency nuclear type 12, MC4DN12) is a rare autosomal recessive nuclear form of isolated cytochrome c oxidase (COX, Complex IV) deficiency caused by biallelic variants in PET100 (formerly C19orf79). PET100 is a small mitochondrial inner-membrane chaperone that acts at an intermediate stage of Complex IV biogenesis, promoting incorporation of the COX subunits into the maturing holoenzyme. Loss of PET100 leaves the COX subunits unstable and blocks assembly of fully assembled Complex IV, producing an isolated Complex IV deficiency. The clinical spectrum spans a Lebanese founder mutation presenting as complex IV-deficient Leigh syndrome with prominent seizures, through a fatal neonatal-onset isolated COX deficiency with severe lactic acidosis and multiorgan involvement reported outside the Lebanese population. It conforms to the conserved Complex IV assembly-deficiency mechanism, with the lesion localized to failed holoenzyme assembly.

Ask OpenScientist

Ask a research question about PET100-Related COX Deficiency. OpenScientist will conduct autonomous deep research using the Disorder Mechanisms Knowledge Base and PubMed literature (typically 10-30 minutes).

Submitting...

Do not include personal health information in your question. Questions and results are cached in your browser's local storage.

⚙

Pathophysiology

PET100 Loss and Failed Complex IV Assembly

Biallelic PET100 variants cause loss of a small mitochondrial inner-membrane Complex IV biogenesis factor. PET100 forms a subcomplex with Complex IV subunits and is required for their incorporation into the maturing holoenzyme; in its absence the COX subunits are destabilized and the holoenzyme fails to assemble, yielding isolated Complex IV biogenesis failure.

mitochondrial respiratory chain complex IV assembly GO:0033617 ↓ DECREASED

Downstream

Impaired Terminal Electron Transfer and ATP Synthesis Failure to assemble Complex IV yields a catalytically deficient holoenzyme.

Show evidence (4 references)

PMID:24462369 SUPPORT Human Clinical

"C19orf79 was recently renamed PET100 and predicted to encode a complex IV biogenesis factor."

Establishes PET100 (formerly C19orf79) as a Complex IV biogenesis factor whose loss causes isolated Complex IV deficiency.

PMID:24462369 SUPPORT In Vitro

"We showed that it is located in the mitochondrial inner membrane and forms a ∼300 kDa subcomplex with complex IV subunits."

Localizes PET100 to the mitochondrial inner membrane where it forms a subcomplex with Complex IV subunits, consistent with an assembly-factor role.

PMID:25293719 SUPPORT Human Clinical

"Exome sequencing revealed a homozygous truncating variant (c.142C>T, p.(Gln48*)) in the PET100 gene that results in a complete loss of enzyme activity and assembly of the holocomplex."

A truncating PET100 variant abolishes Complex IV enzyme activity and holocomplex assembly, defining the molecular lesion.

+ 1 more reference

Impaired Terminal Electron Transfer and ATP Synthesis

Deficient Complex IV blocks electron transfer from cytochrome c to oxygen and proton pumping, collapsing oxidative ATP synthesis and preferentially injuring high-energy tissue (brain, skeletal muscle).

neuron CL:0000540

mitochondrial electron transport, cytochrome c to oxygen GO:0006123 ↓ DECREASED ATP synthesis coupled electron transport GO:0042775 ↓ DECREASED

Downstream

Lactic Acidosis and Metabolic Decompensation Loss of oxidative ATP synthesis forces anaerobic glycolysis and lactate accumulation.

Neurodevelopmental Leigh Spectrum Injury High-energy CNS tissues are vulnerable to complex IV failure, producing the Leigh-spectrum neurodevelopmental phenotype.

Neonatal Multiorgan Energy Failure Profound complex IV failure disrupts energy homeostasis across neonatal liver, muscle, kidney, and brain.

Bilateral basal ganglia lesions Bioenergetic failure in deep gray matter produces the bilateral brainstem/basal ganglia lesions of Leigh syndrome.

Show evidence (2 references)

PMID:25293719 SUPPORT Human Clinical

"demonstrated a severe and isolated deficiency of complex IV in muscle homogenates"

Patient muscle shows severe isolated Complex IV deficiency, the biochemical basis for impaired terminal electron transfer and ATP synthesis.

PMID:25293719 SUPPORT In Vitro

"The analysis of the steady-state levels of OXPHOS complex components confirmed a marked decrease in COXI and COXII in patient compared with control fibroblasts"

Reduced steady-state Complex IV subunits in patient fibroblasts confirm loss of functional terminal oxidase.

Lactic Acidosis and Metabolic Decompensation

With oxidative phosphorylation blocked, pyruvate is shunted to lactate, elevating blood lactate; in PET100-related disease this can present as a severe, treatment-refractory neonatal lactic acidosis.

lactate biosynthetic process GO:0019249 ↑ INCREASED

Downstream

Lactic acidosis Lactate overproduction manifests clinically as lactic acidosis.

Neonatal Multiorgan Energy Failure Severe lactic acidosis is part of the neonatal metabolic decompensation that accompanies multiorgan energy failure.

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"At a few hours of age, she developed a severe lactic acidosis."

The neonatal patient developed a severe lactic acidosis, the metabolic consequence of failed oxidative ATP synthesis.

Neurodevelopmental Leigh Spectrum Injury

PET100-related complex IV deficiency injures high-energy neural tissues, producing Leigh syndrome with seizures and later neurodevelopmental, motor, respiratory, and growth phenotypes.

neuron CL:0000540

mitochondrial ATP synthesis coupled electron transport GO:0042775 ↓ DECREASED

Downstream

Leigh syndrome CNS energy failure manifests as Leigh-spectrum neurodegeneration.

Seizures Leigh-spectrum CNS injury manifests clinically as seizures.

Global developmental delay Chronic neurodevelopmental injury manifests as global developmental delay.

Muscular hypotonia Motor-system involvement manifests as hypotonia.

Failure to thrive Severe neurodevelopmental and metabolic disease contributes to failure to thrive.

Respiratory insufficiency Severe neurologic and metabolic involvement contributes to respiratory insufficiency.

Show evidence (2 references)

PMID:24462369 SUPPORT Human Clinical

"Leigh syndrome (LS) is a severe neurodegenerative disorder with characteristic bilateral lesions, typically in the brainstem and basal ganglia."

This establishes the neurodegenerative Leigh-spectrum phenotype downstream of PET100-related complex IV deficiency.

PMID:31406627 SUPPORT Human Clinical

"a history of global developmental delay, failure to thrive, muscular hypotonia, seizures, developmental regression, respiratory insufficiency, and lactic acidosis"

Additional founder-allele families support the broader neurodevelopmental and motor phenotype downstream of the Leigh-spectrum branch.

Neonatal Multiorgan Energy Failure

In severe truncating PET100 disease, neonatal complex IV failure disrupts energy homeostasis across multiple organs, with hypoglycemia, renal tubular aminoaciduria, hepatic synthetic dysfunction, skeletal muscle involvement, and prenatal brain-growth effects.

mitochondrial ATP synthesis coupled electron transport GO:0042775 ↓ DECREASED

Downstream

Intrauterine growth retardation Prenatal energy failure contributes to antenatal growth restriction.

Microcephaly Prenatal brain energy failure manifests as severe microcephaly.

Neonatal hypoglycemia Energy-metabolism failure manifests as neonatal hypoglycemia.

Generalized aminoaciduria Renal tubular energy failure manifests as generalized aminoaciduria.

Decreased liver function Hepatic energy failure manifests as decreased liver function.

Prolonged prothrombin time Hepatic synthetic dysfunction manifests as prolonged prothrombin time.

Hypoalbuminemia Hepatic synthetic dysfunction manifests as hypoalbuminemia.

Elevated circulating creatine kinase concentration Skeletal muscle energy failure manifests as elevated creatine kinase.

Show evidence (2 references)

PMID:25293719 SUPPORT Human Clinical

"fatal, neonatal-onset isolated complex IV deficiency associated with multiorgan involvement"

The truncating-variant report defines the severe neonatal multiorgan presentation.

PMID:25293719 SUPPORT Human Clinical

"Further differences in our patient's clinical presentation were marked hypoglycaemia, severely impaired liver function and raised creatine kinase reflecting profound disruption of metabolic energy homeostasis."

This directly links hypoglycemia, liver dysfunction, and elevated CK to profound metabolic energy disruption.

⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

●

Phenotypes

Digestive 1

Decreased liver function Decreased liver function HP:0001410

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"severely impaired liver function"

Severely impaired liver function is highlighted as a distinguishing feature of the truncating-variant neonatal presentation.

Head and Neck 1

Microcephaly Microcephaly HP:0000252

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"head circumference of 26.7 cm, considerably below the 0.4th centile"

The neonatal-onset patient was microcephalic, with a head circumference far below the 0.4th centile that the authors attribute to severe in utero brain development problems.

Metabolism 3

Lactic acidosis Lactic acidosis HP:0003128

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"At a few hours of age, she developed a severe lactic acidosis."

Severe neonatal lactic acidosis is documented in the PET100 truncating-variant patient.

Hypoalbuminemia Hypoalbuminemia HP:0003073

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"a very low plasma albumin of 7 g/l (normal 35–50 g/l)"

Markedly low plasma albumin documents hepatic synthetic failure in the neonatal-onset patient.

Elevated circulating creatine kinase concentration Elevated circulating creatine kinase concentration HP:0003236

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"a raised creatine kinase of 2700 U/l (normal <300 U/l)"

Elevated serum creatine kinase indicates skeletal muscle involvement in the neonatal-onset presentation.

Musculoskeletal 1

Muscular hypotonia Hypotonia HP:0001252

Show evidence (1 reference)

PMID:31406627 SUPPORT Human Clinical

"muscular hypotonia, seizures, developmental regression, respiratory insufficiency, and lactic acidosis"

Muscular hypotonia is documented in affected siblings carrying the Lebanese founder allele.

Nervous System 2

Seizures Seizure HP:0001250

Show evidence (2 references)

PMID:24462369 SUPPORT Human Clinical

"They differed from individuals with SURF1 mutations in having seizures as a prominent feature."

Seizures are a prominent and distinguishing feature of PET100-related Leigh syndrome.

PMID:25293719 SUPPORT Human Clinical

"She started having seizures at ∼48 h of age."

The neonatal-onset patient also developed seizures.

Global developmental delay Global developmental delay HP:0001263

Show evidence (2 references)

PMID:25293719 SUPPORT Human Clinical

"associated with Leigh syndrome, seizures, developmental delay and elevated blood lactate levels"

Developmental delay is reported as a core feature of the Lebanese founder-variant cohort.

PMID:31406627 SUPPORT Human Clinical

"a history of global developmental delay, failure to thrive, muscular hypotonia, seizures, developmental regression, respiratory insufficiency, and lactic acidosis"

Global developmental delay is directly documented in affected siblings carrying the Lebanese founder allele.

Respiratory 1

Respiratory insufficiency Respiratory insufficiency HP:0002093

Show evidence (1 reference)

PMID:31406627 SUPPORT Human Clinical

"developmental regression, respiratory insufficiency, and lactic acidosis"

Respiratory insufficiency is documented in the more severely affected founder-allele siblings.

Growth 2

Intrauterine growth retardation Intrauterine growth retardation HP:0001511

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"Antenatal scans showed that she was small for her gestation, weighing 1.19 kg at birth"

Antenatal growth restriction (small for gestational age) is documented in the neonatal-onset patient.

Failure to thrive Failure to thrive HP:0001508

Show evidence (1 reference)

PMID:31406627 SUPPORT Human Clinical

"global developmental delay, failure to thrive, muscular hypotonia"

Failure to thrive is documented in affected siblings carrying the Lebanese founder allele.

Other 5

Leigh syndrome Neurodegeneration HP:0002180

Show evidence (1 reference)

PMID:24462369 SUPPORT Human Clinical

"Leigh syndrome (LS) is a severe neurodegenerative disorder with characteristic bilateral lesions, typically in the brainstem and basal ganglia."

Defines the Leigh syndrome neurodegenerative phenotype that the PET100 founder mutation produces.

Bilateral basal ganglia lesions Bilateral basal ganglia lesions HP:0007146

Show evidence (1 reference)

PMID:24462369 SUPPORT Human Clinical

"Leigh syndrome (LS) is a severe neurodegenerative disorder with characteristic bilateral lesions, typically in the brainstem and basal ganglia."

The bilateral brainstem/basal ganglia lesions are the defining imaging feature of the PET100-related Leigh phenotype.

Neonatal hypoglycemia Neonatal hypoglycemia HP:0001998

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"She also developed hypoglycaemia within hours of birth"

Neonatal hypoglycemia is documented in the PET100 truncating-variant patient.

Generalized aminoaciduria Generalized aminoaciduria HP:0002909

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"There was gross generalised aminoaciduria."

Generalized aminoaciduria indicates renal tubular involvement in the multiorgan neonatal presentation.

Prolonged prothrombin time Prolonged prothrombin time HP:0008151

Show evidence (1 reference)

PMID:25293719 SUPPORT Human Clinical

"severe coagulopathy with an extended prothrombin time of 47.7 s (normal 12.3–16.6 s)"

Severe coagulopathy with a markedly prolonged prothrombin time documents the hepatic synthetic dysfunction of the neonatal presentation.

🧬

Genetic Associations

PET100 pathogenic variants causing MC4DN12

Gene: PET100 hgnc:40038

Autosomal recessive

Show evidence (3 references)

PMID:24462369 SUPPORT Human Clinical

"We studied eight complex IV-deficient LS individuals from six families of Lebanese origin."

Establishes PET100 as the causal gene across multiple Lebanese Leigh syndrome families sharing a founder mutation.

PMID:25293719 SUPPORT Human Clinical

"Our report confirms PET100 mutation as an important cause of isolated complex IV deficiency outside of the Lebanese population, extending the phenotypic spectrum associated with abnormalities within this gene."

Confirms PET100 as a cause of isolated complex IV deficiency beyond the founder population and broadens the associated phenotype.

PMID:31406627 SUPPORT Human Clinical

"Here, we report two families, of which one is consanguineous, with two affected siblings each."

Two additional Lebanese families with four affected siblings carry the same c.3G>C (p.Met1?) founder allele, confirming its recurrence and importance in the Lebanese population.

💊

Medical Actions

Supportive and Metabolic Care

Action: supportive care MAXO:0000950

No curative therapy exists; management is supportive, addressing seizures, the neurodegenerative course, and metabolic (lactic) acidosis, including bicarbonate buffering of acute decompensation and developmental support.

{ }

Source YAML

click to show

name: PET100-Related COX Deficiency
category: Mendelian
creation_date: "2026-06-16T00:00:00Z"
synonyms:
- PET100 deficiency
- Mitochondrial complex IV deficiency, nuclear type 12
- MC4DN12
- PET100-related cytochrome c oxidase deficiency
- C19orf79-related complex IV deficiency
description: >
  PET100-related COX deficiency (mitochondrial complex IV deficiency nuclear
  type 12, MC4DN12) is a rare autosomal recessive nuclear form of isolated
  cytochrome c oxidase (COX, Complex IV) deficiency caused by biallelic variants
  in PET100 (formerly C19orf79). PET100 is a small mitochondrial inner-membrane
  chaperone that acts at an intermediate stage of Complex IV biogenesis,
  promoting incorporation of the COX subunits into the maturing holoenzyme. Loss
  of PET100 leaves the COX subunits unstable and blocks assembly of fully
  assembled Complex IV, producing an isolated Complex IV deficiency. The
  clinical spectrum spans a Lebanese founder mutation presenting as
  complex IV-deficient Leigh syndrome with prominent seizures, through a fatal
  neonatal-onset isolated COX deficiency with severe lactic acidosis and
  multiorgan involvement reported outside the Lebanese population. It conforms to
  the conserved Complex IV assembly-deficiency mechanism, with the lesion
  localized to failed holoenzyme assembly.
disease_term:
  preferred_term: PET100-related COX deficiency (MC4DN12)
  term:
    id: MONDO:0033646
    label: mitochondrial complex IV deficiency, nuclear type 12
parents:
- Mitochondrial Disease
- Inborn Error of Metabolism
references:
- reference: PMID:26425749
  title: "Nuclear Gene-Encoded Leigh Syndrome Spectrum Overview."
  tags:
  - GeneReviews
pathophysiology:
- name: PET100 Loss and Failed Complex IV Assembly
  conforms_to: "complex_iv_assembly_deficiency#Complex IV Biogenesis Failure"
  description: >
    Biallelic PET100 variants cause loss of a small mitochondrial inner-membrane
    Complex IV biogenesis factor. PET100 forms a subcomplex with Complex IV
    subunits and is required for their incorporation into the maturing
    holoenzyme; in its absence the COX subunits are destabilized and the
    holoenzyme fails to assemble, yielding isolated Complex IV biogenesis
    failure.
  biological_processes:
  - preferred_term: mitochondrial respiratory chain complex IV assembly
    term:
      id: GO:0033617
      label: mitochondrial respiratory chain complex IV assembly
    modifier: DECREASED
  evidence:
  - reference: PMID:24462369
    reference_title: "A founder mutation in PET100 causes isolated complex IV deficiency in Lebanese individuals with Leigh syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: C19orf79 was recently renamed PET100 and predicted to encode a complex IV biogenesis factor.
    explanation: Establishes PET100 (formerly C19orf79) as a Complex IV biogenesis factor whose loss causes isolated Complex IV deficiency.
  - reference: PMID:24462369
    reference_title: "A founder mutation in PET100 causes isolated complex IV deficiency in Lebanese individuals with Leigh syndrome."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: We showed that it is located in the mitochondrial inner membrane and forms a ∼300 kDa subcomplex with complex IV subunits.
    explanation: Localizes PET100 to the mitochondrial inner membrane where it forms a subcomplex with Complex IV subunits, consistent with an assembly-factor role.
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Exome sequencing revealed a homozygous truncating variant (c.142C>T, p.(Gln48*)) in the PET100 gene that results in a complete loss of enzyme activity and assembly of the holocomplex.
    explanation: A truncating PET100 variant abolishes Complex IV enzyme activity and holocomplex assembly, defining the molecular lesion.
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: BN-PAGE analysis revealed significantly decreased amounts of fully assembled complex IV in patient cells compared with age-matched controls
    explanation: Patient fibroblasts show a profound defect in assembly of fully formed Complex IV, demonstrating failed biogenesis.
  downstream:
  - target: Impaired Terminal Electron Transfer and ATP Synthesis
    causal_link_type: DIRECT
    description: Failure to assemble Complex IV yields a catalytically deficient holoenzyme.
- name: Impaired Terminal Electron Transfer and ATP Synthesis
  conforms_to: "complex_iv_assembly_deficiency#Impaired Terminal Electron Transfer and ATP Synthesis"
  description: >
    Deficient Complex IV blocks electron transfer from cytochrome c to oxygen
    and proton pumping, collapsing oxidative ATP synthesis and preferentially
    injuring high-energy tissue (brain, skeletal muscle).
  cell_types:
  - preferred_term: neuron
    term:
      id: CL:0000540
      label: neuron
  biological_processes:
  - preferred_term: mitochondrial electron transport, cytochrome c to oxygen
    term:
      id: GO:0006123
      label: mitochondrial electron transport, cytochrome c to oxygen
    modifier: DECREASED
  - preferred_term: ATP synthesis coupled electron transport
    term:
      id: GO:0042775
      label: mitochondrial ATP synthesis coupled electron transport
    modifier: DECREASED
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: demonstrated a severe and isolated deficiency of complex IV in muscle homogenates
    explanation: Patient muscle shows severe isolated Complex IV deficiency, the biochemical basis for impaired terminal electron transfer and ATP synthesis.
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: The analysis of the steady-state levels of OXPHOS complex components confirmed a marked decrease in COXI and COXII in patient compared with control fibroblasts
    explanation: Reduced steady-state Complex IV subunits in patient fibroblasts confirm loss of functional terminal oxidase.
  downstream:
  - target: Lactic Acidosis and Metabolic Decompensation
    causal_link_type: DIRECT
    description: Loss of oxidative ATP synthesis forces anaerobic glycolysis and lactate accumulation.
  - target: Neurodevelopmental Leigh Spectrum Injury
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      High-energy CNS tissues are vulnerable to complex IV failure, producing
      the Leigh-spectrum neurodevelopmental phenotype.
  - target: Neonatal Multiorgan Energy Failure
    causal_link_type: DIRECT
    description: >-
      Profound complex IV failure disrupts energy homeostasis across neonatal
      liver, muscle, kidney, and brain.
  - target: Bilateral basal ganglia lesions
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: Bioenergetic failure in deep gray matter produces the bilateral brainstem/basal ganglia lesions of Leigh syndrome.
- name: Lactic Acidosis and Metabolic Decompensation
  conforms_to: "complex_iv_assembly_deficiency#Lactic Acidosis and Metabolic Decompensation"
  description: >
    With oxidative phosphorylation blocked, pyruvate is shunted to lactate,
    elevating blood lactate; in PET100-related disease this can present as a
    severe, treatment-refractory neonatal lactic acidosis.
  biological_processes:
  - preferred_term: lactate biosynthetic process
    term:
      id: GO:0019249
      label: lactate biosynthetic process
    modifier: INCREASED
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: At a few hours of age, she developed a severe lactic acidosis.
    explanation: The neonatal patient developed a severe lactic acidosis, the metabolic consequence of failed oxidative ATP synthesis.
  downstream:
  - target: Lactic acidosis
    causal_link_type: DIRECT
    description: Lactate overproduction manifests clinically as lactic acidosis.
  - target: Neonatal Multiorgan Energy Failure
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Severe lactic acidosis is part of the neonatal metabolic decompensation
      that accompanies multiorgan energy failure.
- name: Neurodevelopmental Leigh Spectrum Injury
  description: >
    PET100-related complex IV deficiency injures high-energy neural tissues,
    producing Leigh syndrome with seizures and later neurodevelopmental,
    motor, respiratory, and growth phenotypes.
  cell_types:
  - preferred_term: neuron
    term:
      id: CL:0000540
      label: neuron
  biological_processes:
  - preferred_term: mitochondrial ATP synthesis coupled electron transport
    term:
      id: GO:0042775
      label: mitochondrial ATP synthesis coupled electron transport
    modifier: DECREASED
  evidence:
  - reference: PMID:24462369
    reference_title: "A founder mutation in PET100 causes isolated complex IV deficiency in Lebanese individuals with Leigh syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Leigh syndrome (LS) is a severe neurodegenerative disorder with characteristic bilateral lesions, typically in the brainstem and basal ganglia.
    explanation: >
      This establishes the neurodegenerative Leigh-spectrum phenotype
      downstream of PET100-related complex IV deficiency.
  - reference: PMID:31406627
    reference_title: "The Lebanese Allele in the PET100 Gene: Report on Two New Families with Cytochrome c Oxidase Deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: a history of global developmental delay, failure to thrive, muscular hypotonia, seizures, developmental regression, respiratory insufficiency, and lactic acidosis
    explanation: >
      Additional founder-allele families support the broader
      neurodevelopmental and motor phenotype downstream of the Leigh-spectrum
      branch.
  downstream:
  - target: Leigh syndrome
    causal_link_type: DIRECT
    description: CNS energy failure manifests as Leigh-spectrum neurodegeneration.
  - target: Seizures
    causal_link_type: DIRECT
    description: Leigh-spectrum CNS injury manifests clinically as seizures.
  - target: Global developmental delay
    causal_link_type: DIRECT
    description: Chronic neurodevelopmental injury manifests as global developmental delay.
  - target: Muscular hypotonia
    causal_link_type: DIRECT
    description: Motor-system involvement manifests as hypotonia.
  - target: Failure to thrive
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: Severe neurodevelopmental and metabolic disease contributes to failure to thrive.
  - target: Respiratory insufficiency
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: Severe neurologic and metabolic involvement contributes to respiratory insufficiency.
- name: Neonatal Multiorgan Energy Failure
  description: >
    In severe truncating PET100 disease, neonatal complex IV failure disrupts
    energy homeostasis across multiple organs, with hypoglycemia, renal tubular
    aminoaciduria, hepatic synthetic dysfunction, skeletal muscle involvement,
    and prenatal brain-growth effects.
  biological_processes:
  - preferred_term: mitochondrial ATP synthesis coupled electron transport
    term:
      id: GO:0042775
      label: mitochondrial ATP synthesis coupled electron transport
    modifier: DECREASED
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: fatal, neonatal-onset isolated complex IV deficiency associated with multiorgan involvement
    explanation: >
      The truncating-variant report defines the severe neonatal multiorgan
      presentation.
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Further differences in our patient's clinical presentation were marked hypoglycaemia, severely impaired liver function and raised creatine kinase reflecting profound disruption of metabolic energy homeostasis.
    explanation: >
      This directly links hypoglycemia, liver dysfunction, and elevated CK to
      profound metabolic energy disruption.
  downstream:
  - target: Intrauterine growth retardation
    causal_link_type: DIRECT
    description: Prenatal energy failure contributes to antenatal growth restriction.
  - target: Microcephaly
    causal_link_type: DIRECT
    description: Prenatal brain energy failure manifests as severe microcephaly.
  - target: Neonatal hypoglycemia
    causal_link_type: DIRECT
    description: Energy-metabolism failure manifests as neonatal hypoglycemia.
  - target: Generalized aminoaciduria
    causal_link_type: DIRECT
    description: Renal tubular energy failure manifests as generalized aminoaciduria.
  - target: Decreased liver function
    causal_link_type: DIRECT
    description: Hepatic energy failure manifests as decreased liver function.
  - target: Prolonged prothrombin time
    causal_link_type: DIRECT
    description: Hepatic synthetic dysfunction manifests as prolonged prothrombin time.
  - target: Hypoalbuminemia
    causal_link_type: DIRECT
    description: Hepatic synthetic dysfunction manifests as hypoalbuminemia.
  - target: Elevated circulating creatine kinase concentration
    causal_link_type: DIRECT
    description: Skeletal muscle energy failure manifests as elevated creatine kinase.
phenotypes:
- name: Leigh syndrome
  description: >
    Complex IV-deficient Leigh syndrome, a severe infantile-onset
    neurodegenerative disorder, is the presentation of the Lebanese PET100
    founder mutation.
  phenotype_term:
    preferred_term: Neurodegeneration
    term:
      id: HP:0002180
      label: Neurodegeneration
  evidence:
  - reference: PMID:24462369
    reference_title: "A founder mutation in PET100 causes isolated complex IV deficiency in Lebanese individuals with Leigh syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Leigh syndrome (LS) is a severe neurodegenerative disorder with characteristic bilateral lesions, typically in the brainstem and basal ganglia.
    explanation: Defines the Leigh syndrome neurodegenerative phenotype that the PET100 founder mutation produces.
- name: Bilateral basal ganglia lesions
  description: >
    Characteristic bilateral lesions of the brainstem and basal ganglia, the
    neuroradiological hallmark of Leigh syndrome.
  phenotype_term:
    preferred_term: Bilateral basal ganglia lesions
    term:
      id: HP:0007146
      label: Bilateral basal ganglia lesions
  evidence:
  - reference: PMID:24462369
    reference_title: "A founder mutation in PET100 causes isolated complex IV deficiency in Lebanese individuals with Leigh syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Leigh syndrome (LS) is a severe neurodegenerative disorder with characteristic bilateral lesions, typically in the brainstem and basal ganglia.
    explanation: The bilateral brainstem/basal ganglia lesions are the defining imaging feature of the PET100-related Leigh phenotype.
- name: Seizures
  description: >
    Seizures are a prominent feature distinguishing PET100-related Leigh
    syndrome from SURF1-related disease, and were also seen in the fatal
    neonatal presentation.
  phenotype_term:
    preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
  evidence:
  - reference: PMID:24462369
    reference_title: "A founder mutation in PET100 causes isolated complex IV deficiency in Lebanese individuals with Leigh syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: They differed from individuals with SURF1 mutations in having seizures as a prominent feature.
    explanation: Seizures are a prominent and distinguishing feature of PET100-related Leigh syndrome.
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: She started having seizures at ∼48 h of age.
    explanation: The neonatal-onset patient also developed seizures.
- name: Lactic acidosis
  description: >
    Severe, often treatment-refractory lactic acidosis, prominent in the
    neonatal-onset presentation.
  phenotype_term:
    preferred_term: Lactic acidosis
    term:
      id: HP:0003128
      label: Lactic acidosis
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: At a few hours of age, she developed a severe lactic acidosis.
    explanation: Severe neonatal lactic acidosis is documented in the PET100 truncating-variant patient.
- name: Intrauterine growth retardation
  description: >
    Antenatal growth restriction, reported in the fatal neonatal-onset
    presentation.
  phenotype_term:
    preferred_term: Intrauterine growth retardation
    term:
      id: HP:0001511
      label: Intrauterine growth retardation
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Antenatal scans showed that she was small for her gestation, weighing 1.19 kg at birth
    explanation: Antenatal growth restriction (small for gestational age) is documented in the neonatal-onset patient.
- name: Neonatal hypoglycemia
  description: >
    Hypoglycemia developing within hours of birth in the neonatal-onset
    presentation.
  phenotype_term:
    preferred_term: Neonatal hypoglycemia
    term:
      id: HP:0001998
      label: Neonatal hypoglycemia
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: She also developed hypoglycaemia within hours of birth
    explanation: Neonatal hypoglycemia is documented in the PET100 truncating-variant patient.
- name: Generalized aminoaciduria
  description: >
    Gross generalized aminoaciduria, reflecting renal tubular involvement in the
    neonatal-onset multiorgan presentation.
  phenotype_term:
    preferred_term: Generalized aminoaciduria
    term:
      id: HP:0002909
      label: Generalized aminoaciduria
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: There was gross generalised aminoaciduria.
    explanation: Generalized aminoaciduria indicates renal tubular involvement in the multiorgan neonatal presentation.
- name: Microcephaly
  description: >
    Severe microcephaly with antenatal onset, reflecting disrupted in utero
    brain development in the fatal neonatal-onset (truncating-variant)
    presentation.
  phenotype_term:
    preferred_term: Microcephaly
    term:
      id: HP:0000252
      label: Microcephaly
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: head circumference of 26.7 cm, considerably below the 0.4th centile
    explanation: The neonatal-onset patient was microcephalic, with a head circumference far below the 0.4th centile that the authors attribute to severe in utero brain development problems.
- name: Decreased liver function
  description: >
    Severely impaired liver function in the neonatal-onset multiorgan
    presentation, part of the profound disruption of metabolic energy
    homeostasis.
  phenotype_term:
    preferred_term: Decreased liver function
    term:
      id: HP:0001410
      label: Decreased liver function
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: severely impaired liver function
    explanation: Severely impaired liver function is highlighted as a distinguishing feature of the truncating-variant neonatal presentation.
- name: Prolonged prothrombin time
  description: >
    Severe coagulopathy with markedly prolonged prothrombin time, reflecting
    hepatic synthetic dysfunction in the neonatal-onset presentation.
  phenotype_term:
    preferred_term: Prolonged prothrombin time
    term:
      id: HP:0008151
      label: Prolonged prothrombin time
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: severe coagulopathy with an extended prothrombin time of 47.7 s (normal 12.3–16.6 s)
    explanation: Severe coagulopathy with a markedly prolonged prothrombin time documents the hepatic synthetic dysfunction of the neonatal presentation.
- name: Hypoalbuminemia
  description: >
    Very low plasma albumin in the neonatal-onset presentation, reflecting
    hepatic synthetic failure.
  phenotype_term:
    preferred_term: Hypoalbuminemia
    term:
      id: HP:0003073
      label: Hypoalbuminemia
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: a very low plasma albumin of 7 g/l (normal 35–50 g/l)
    explanation: Markedly low plasma albumin documents hepatic synthetic failure in the neonatal-onset patient.
- name: Elevated circulating creatine kinase concentration
  description: >
    Raised serum creatine kinase indicating skeletal muscle involvement in the
    neonatal-onset multiorgan presentation.
  phenotype_term:
    preferred_term: Elevated circulating creatine kinase concentration
    term:
      id: HP:0003236
      label: Elevated circulating creatine kinase concentration
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: a raised creatine kinase of 2700 U/l (normal <300 U/l)
    explanation: Elevated serum creatine kinase indicates skeletal muscle involvement in the neonatal-onset presentation.
- name: Global developmental delay
  description: >
    Developmental delay was a feature of the infantile-onset Lebanese founder
    cohort, alongside Leigh syndrome and seizures.
  phenotype_term:
    preferred_term: Global developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: associated with Leigh syndrome, seizures, developmental delay and elevated blood lactate levels
    explanation: Developmental delay is reported as a core feature of the Lebanese founder-variant cohort.
  - reference: PMID:31406627
    reference_title: "The Lebanese Allele in the PET100 Gene: Report on Two New Families with Cytochrome c Oxidase Deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: a history of global developmental delay, failure to thrive, muscular hypotonia, seizures, developmental regression, respiratory insufficiency, and lactic acidosis
    explanation: Global developmental delay is directly documented in affected siblings carrying the Lebanese founder allele.
- name: Muscular hypotonia
  description: >
    Muscular hypotonia, reported in affected siblings of the Lebanese
    founder-allele families.
  phenotype_term:
    preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia
  evidence:
  - reference: PMID:31406627
    reference_title: "The Lebanese Allele in the PET100 Gene: Report on Two New Families with Cytochrome c Oxidase Deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: muscular hypotonia, seizures, developmental regression, respiratory insufficiency, and lactic acidosis
    explanation: Muscular hypotonia is documented in affected siblings carrying the Lebanese founder allele.
- name: Failure to thrive
  description: >
    Failure to thrive, reported in affected siblings of the Lebanese
    founder-allele families.
  phenotype_term:
    preferred_term: Failure to thrive
    term:
      id: HP:0001508
      label: Failure to thrive
  evidence:
  - reference: PMID:31406627
    reference_title: "The Lebanese Allele in the PET100 Gene: Report on Two New Families with Cytochrome c Oxidase Deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: global developmental delay, failure to thrive, muscular hypotonia
    explanation: Failure to thrive is documented in affected siblings carrying the Lebanese founder allele.
- name: Respiratory insufficiency
  description: >
    Respiratory insufficiency in the more severe Lebanese founder-allele
    presentation, contributing to early death.
  phenotype_term:
    preferred_term: Respiratory insufficiency
    term:
      id: HP:0002093
      label: Respiratory insufficiency
  evidence:
  - reference: PMID:31406627
    reference_title: "The Lebanese Allele in the PET100 Gene: Report on Two New Families with Cytochrome c Oxidase Deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: developmental regression, respiratory insufficiency, and lactic acidosis
    explanation: Respiratory insufficiency is documented in the more severely affected founder-allele siblings.
genetic:
- name: PET100 pathogenic variants causing MC4DN12
  gene_term:
    preferred_term: PET100
    term:
      id: hgnc:40038
      label: PET100
  inheritance:
  - name: Autosomal recessive
    evidence:
    - reference: PMID:24462369
      reference_title: "A founder mutation in PET100 causes isolated complex IV deficiency in Lebanese individuals with Leigh syndrome."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: a homozygous c.3G>C (p.Met1?) mutation in C19orf79
      explanation: A homozygous PET100 (C19orf79) mutation segregating in consanguineous Lebanese families establishes autosomal recessive inheritance.
  features: >
    Biallelic PET100 variants cause MC4DN12. A homozygous initiation-codon
    variant (c.3G>C, p.Met1?) is a Lebanese founder mutation underlying
    complex IV-deficient Leigh syndrome, and a homozygous truncating variant
    (c.142C>T, p.(Gln48*)) was identified in a non-Lebanese patient with fatal
    neonatal lactic acidosis, extending the phenotypic spectrum.
  evidence:
  - reference: PMID:24462369
    reference_title: "A founder mutation in PET100 causes isolated complex IV deficiency in Lebanese individuals with Leigh syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: We studied eight complex IV-deficient LS individuals from six families of Lebanese origin.
    explanation: Establishes PET100 as the causal gene across multiple Lebanese Leigh syndrome families sharing a founder mutation.
  - reference: PMID:25293719
    reference_title: "A truncating PET100 variant causing fatal infantile lactic acidosis and isolated cytochrome c oxidase deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Our report confirms PET100 mutation as an important cause of isolated complex IV deficiency outside of the Lebanese population, extending the phenotypic spectrum associated with abnormalities within this gene.
    explanation: Confirms PET100 as a cause of isolated complex IV deficiency beyond the founder population and broadens the associated phenotype.
  - reference: PMID:31406627
    reference_title: "The Lebanese Allele in the PET100 Gene: Report on Two New Families with Cytochrome c Oxidase Deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Here, we report two families, of which one is consanguineous, with two affected siblings each."
    explanation: Two additional Lebanese families with four affected siblings carry the same c.3G>C (p.Met1?) founder allele, confirming its recurrence and importance in the Lebanese population.
treatments:
- name: Supportive and Metabolic Care
  description: >
    No curative therapy exists; management is supportive, addressing seizures,
    the neurodegenerative course, and metabolic (lactic) acidosis, including
    bicarbonate buffering of acute decompensation and developmental support.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care

📚

References & Deep Research

References

PMID:26425749

Nuclear Gene-Encoded Leigh Syndrome Spectrum Overview.

No top-level findings curated for this source.

Deep Research

Claude Deep Research ▸

PET100-Related Cytochrome c Oxidase (Complex IV) Deficiency — Deep Research Report

claude-opus-4-8

PET100-Related Cytochrome c Oxidase (Complex IV) Deficiency — Deep Research Report

Disease: PET100-Related COX Deficiency (mitochondrial complex IV deficiency, nuclear type 12; MC4DN12) MONDO: MONDO:0033646 | OMIM phenotype: 619055 | Gene: PET100 (HGNC:40038; formerly C19orf79) | Inheritance: autosomal recessive

Executive Summary

PET100-related Complex IV (cytochrome c oxidase, COX) deficiency is an ultra-rare autosomal recessive mitochondrial disorder caused by biallelic loss-of-function variants in the small nuclear-encoded inner-mitochondrial-membrane Complex IV biogenesis factor PET100 (formerly C19orf79). PET100 forms a ~300 kDa subcomplex with COX subunits and is required for their incorporation into the maturing holoenzyme; its loss produces an isolated Complex IV biogenesis defect.

The primary human literature is small and, after this sweep, considered essentially complete. It comprises three primary reports:

Lim et al., 2014 (PMID:24462369, Am J Hum Genet) — the founder report: eight Complex IV-deficient Leigh syndrome individuals from six Lebanese families homozygous for the initiation-codon allele c.3G>C (p.Met1?); seizures prominent (distinguishing them from SURF1 disease). PET100 localized to the inner membrane forming a ~300 kDa subcomplex with COX subunits.
Oláhová et al., 2015 (PMID:25293719, Eur J Hum Genet) — a single non-Lebanese (British Pakistani) neonate homozygous for the truncating allele c.142C>T (p.Gln48*) with fatal neonatal-onset multiorgan disease: severe lactic acidosis, microcephaly, hypoglycemia, generalized aminoaciduria, coagulopathy/hypoalbuminemia ("severely impaired liver function"), and raised creatine kinase. This extended the phenotype beyond the founder population.
Mansour et al., 2019 (PMID:31406627, J Pediatr Genet) — newly surfaced by this sweep; was NOT cited in the original entry. Two further Lebanese families (one consanguineous), four affected siblings total, again carrying the founder c.3G>C (p.Met1?) allele, with developmental delay, seizures, lactic acidosis, abnormal brain MRI, low (~30%) muscle Complex IV activity, and in the more severe sibship failure to thrive, muscular hypotonia, developmental regression, and respiratory insufficiency.

A GeneReviews overview, Nuclear Gene-Encoded Leigh Syndrome Spectrum Overview (PMID:26425749), provides authoritative baseline context for the Leigh syndrome spectrum to which PET100 disease belongs and has been added as a tagged top-level reference.

No curative therapy exists; management is supportive (seizure control, buffering of metabolic acidosis, developmental support).

1. Literature Completeness Check (the point of this sweep)

Reference	Year	Cohort	Allele	Status in entry
PMID:24462369 (Lim)	2014	8 individuals / 6 Lebanese families	c.3G>C (p.Met1?)	cited
PMID:25293719 (Oláhová)	2015	1 neonate (British Pakistani)	c.142C>T (p.Gln48*)	cited
PMID:31406627 (Mansour)	2019	4 siblings / 2 Lebanese families	c.3G>C (p.Met1?)	added in this PR
PMID:26425749 (GeneReviews)	overview	—	—	added in this PR (tag)

Two independent WebSearch queries (gene/disorder synonyms; recent-cohort framing 2020–2025) returned no additional primary clinical reports beyond the three above. The 2020–2025 sweep surfaced only secondary resources (GeneCards, OMIM #619055, GTR, PreventionGenetics test pages) — no new patient cohorts — supporting the conclusion that the primary literature is near-complete and dominated by the Lebanese founder allele.

2. Gene and Protein Function

PET100 (formerly C19orf79) encodes a small (~9 kDa) Complex IV biogenesis factor localized to the mitochondrial inner membrane, exposed to the intermembrane space. It forms a ~300 kDa subcomplex with COX subunits and acts at an intermediate stage of holoenzyme assembly (PMID:24462369). In yeast the homolog acts late in COX assembly; human PET100 appears required earlier, for assembly of mtDNA-encoded COX subunits (PMID:25293719 discussion).
Loss of PET100 destabilizes COX subunits and blocks assembly of fully formed Complex IV, yielding isolated Complex IV deficiency (other OXPHOS complexes intact on BN-PAGE).

3. Genotype–Phenotype Notes

c.3G>C (p.Met1?) — Lebanese founder allele; infantile-onset Leigh / Leigh-like syndrome with prominent seizures, developmental delay, variable lactic acidosis, basal ganglia lesions; residual muscle COX activity ~30%. Recurs across Lebanese families (PMID:24462369, PMID:31406627).
c.142C>T (p.Gln48*) — single truncating allele; far more severe, prenatal-onset with neonatal death, extreme lactic acidosis (peak 63 mmol/l), microcephaly, multiorgan involvement (hepatic, renal, skeletal muscle) not seen with the founder allele (PMID:25293719).

4. Treatment

No disease-modifying therapy. Supportive/metabolic care only (bicarbonate/THAM buffering of acute acidosis, anticonvulsants, developmental support) — consistent across all reports.

Caveats

This was a focused completeness sweep, not the full multi-angle adversarial harness; it was scoped to the literature-gap question the reviewer raised. All clinical claims used as evidence in the YAML are independently snippet-validated against just fetch-reference-cached primary sources via just validate-references.
The primary literature is dominated by a single founder allele in one population; generalization of genotype–phenotype correlations is limited by small N (~13 reported individuals total across three papers).

Ask OpenScientist

OpenScientist Report

Pathophysiology

Pathograph

Phenotypes

Genetic Associations

Medical Actions

Source YAML

References & Deep Research

References

Deep Research

PET100-Related Cytochrome c Oxidase (Complex IV) Deficiency — Deep Research Report

Executive Summary

1. Literature Completeness Check (the point of this sweep)

2. Gene and Protein Function

3. Genotype–Phenotype Notes

4. Treatment

Caveats