Mitochondrial Trifunctional Protein Deficiency

Mendelian MONDO:0012172 Pathograph 36 Fatty Acid Oxidation Disorder Inborn Error of Metabolism

Mitochondrial trifunctional protein (MTP) deficiency is a rare autosomal recessive disorder of mitochondrial long-chain fatty acid beta-oxidation caused by biallelic pathogenic variants in HADHA (encoding the alpha subunit) or HADHB (encoding the beta subunit) of the heterooctameric mitochondrial trifunctional protein complex. MTP harbors three enzymatic activities: long-chain enoyl-CoA hydratase, long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD), and long-chain 3-ketoacyl-CoA thiolase (LCKAT). Complete deficiency of all three activities results in MTP deficiency, which is clinically heterogeneous, ranging from severe neonatal presentations with cardiomyopathy, hypoglycemia, and early death, to milder later-onset forms with peripheral neuropathy and episodic rhabdomyolysis. The mortality is high, reported as 57.9% in a large retrospective analysis. HADHB mutations are more frequent in Asian populations and are associated with atypical presentations. Maternal HELLP syndrome and acute fatty liver of pregnancy may be associated with pregnancies carrying affected fetuses.

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Mappings

Definitions

Inheritance

Histopathology

Differentials

Datasets

Trials

Models

References

Deep Research

🏷

Classifications

Harrison's Chapter

Mechanistic Nosology

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Subtypes

Severe neonatal form

Presents in the first days to weeks of life with cardiomyopathy, hypoglycemia, hepatic dysfunction, and multiorgan failure. High mortality. Generally characterized by multiorgan involvement.

Infantile hepatic form

Presents in infancy with hypoketotic hypoglycemia, hepatomegaly, and hepatic dysfunction. May include cardiomyopathy.

Late-onset myopathic form

Presents in childhood or adulthood with progressive peripheral neuropathy, episodic rhabdomyolysis, exercise intolerance, and possible retinopathy. More commonly associated with HADHB mutations.

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Pathophysiology

HADHA/HADHB molecular function deficiency in mitochondrial trifunctional protein

Biallelic pathogenic variants in HADHA or HADHB reduce catalytic activities of the mitochondrial trifunctional protein complex.

HADHA link HADHB link

fatty acid beta-oxidation link ↓ DECREASED

enoyl-CoA hydratase activity link ↓ DECREASED long-chain 3-hydroxyacyl-CoA dehydrogenase activity link ↓ DECREASED 3-ketoacyl-CoA thiolase activity link ↓ DECREASED

mitochondrial inner membrane link

Downstream

Impaired mitochondrial long-chain fatty acid beta-oxidation Reduced TFP catalytic function limits sequential long-chain FAO reactions.

Show evidence (1 reference)

PMID:34543737 SUPPORT Human Clinical

"Mitochondrial trifunctional protein (TFP) deficiency is an autosomal recessive disorder that causes a clinical spectrum of diseases ranging from severe infantile cardiomyopathy to mild chronic progressive neuromyopathy"

Supports proximal molecular dysfunction of TFP encoded by HADHA/HADHB.

Impaired mitochondrial long-chain fatty acid beta-oxidation

The mitochondrial trifunctional protein is a heterooctamer (alpha4-beta4) on the inner mitochondrial membrane that catalyzes three sequential steps of long-chain fatty acid beta-oxidation. Deficiency impairs long-chain FAO, causing stress-dependent energy failure and accumulation of toxic long-chain acylcarnitine intermediates.

hepatocyte link cardiac muscle cell link skeletal muscle fiber link

fatty acid beta-oxidation link ↓ DECREASED long-chain fatty acid metabolic process link ↓ DECREASED

mitochondrial inner membrane link

Downstream

Uncoupling of cardiac oxidative phosphorylation by long-chain 3-hydroxy fatty acids Blocked long-chain FAO causes accumulation of long-chain 3-hydroxy fatty acids that impair mitochondrial oxidative phosphorylation.

Impaired energy production during catabolic stress Loss of long-chain FAO limits ATP production when tissues rely on fatty acids during fasting, illness, or sustained exercise.

Long-chain 3-hydroxyacylcarnitines (C16-OH, C18:1-OH) Impaired TFP-dependent oxidation produces elevated long-chain hydroxyacylcarnitines used in newborn screening and biochemical diagnosis.

Long-chain acylcarnitines Impaired long-chain FAO leads to elevated long-chain acylcarnitines on tandem mass spectrometry.

Hepatic lipid accumulation Failure to oxidize fatty acids causes lipid accumulation in liver and heart.

Long-chain 3-hydroxy fatty acids Incomplete long-chain fatty acid beta-oxidation causes accumulation of hydroxylated long-chain fatty acids.

Hypoparathyroidism Complete TFP deficiency can include atypical parathyroid involvement, although the intervening mechanism is not defined.

Show evidence (2 references)

PMID:29502916 SUPPORT Other

"The subsequent 3 steps for long-chain substrates are catalyzed by trifunctional protein (TFP), a heterooctomer encompassing all 3 remaining enzymatic activities."

Supports TFP as the enzyme complex required for long-chain fatty acid beta-oxidation.

PMID:34543737 SUPPORT Human Clinical

Supports impaired long-chain FAO and downstream tissue injury in MTP deficiency.

Uncoupling of cardiac oxidative phosphorylation by long-chain 3-hydroxy fatty acids

Long-chain 3-hydroxy fatty acids that accumulate in MTP deficiency (3-hydroxytetradecanoic acid, 3-hydroxypalmitic acid) act as potent uncouplers of oxidative phosphorylation in heart mitochondria. They increase resting respiration, diminish the respiratory control ratio, decrease mitochondrial membrane potential, and can induce mitochondrial permeability transition pore opening in calcium-loaded organelles. This mechanism contributes to the cardiomyopathy and energy failure seen in MTP deficiency.

cardiac muscle cell link

oxidative phosphorylation link ↓ DECREASED

heart link

Downstream

Impaired energy production during catabolic stress Uncoupling of oxidative phosphorylation worsens ATP shortage during catabolic stress.

Cardiomyopathy Long-chain 3-hydroxy fatty acids uncouple cardiac mitochondrial oxidative phosphorylation, contributing to cardiomyopathy.

Neurotoxicity from long-chain fatty acid metabolite accumulation Chronic accumulation of long-chain fatty-acid intermediates is linked to later neuromuscular complications.

Retinopathy Chronic TFP/LCHAD-related fatty acid oxidation toxicity is associated with pigmentary retinopathy and retinal degeneration.

Show evidence (1 reference)

PMID:23065309 SUPPORT In Vitro

"3 HTA and 3 HPA increased resting respiration and diminished the respiratory control and ADP/O ratios using glutamate/malate or succinate as substrates."

Confirms uncoupling effects of specific 3-hydroxy fatty acids on mitochondrial respiration.

Impaired energy production during catabolic stress

During fasting, illness, or prolonged exercise, the body relies heavily on long-chain fatty acid oxidation for energy. In MTP deficiency, this metabolic pathway is blocked, leading to hypoketotic hypoglycemia because both hepatic gluconeogenesis and ketogenesis are impaired. The inability to generate adequate ketone bodies as an alternative fuel for brain and heart during fasting contributes to metabolic decompensation, which can be life-threatening.

hepatocyte link cardiac muscle cell link skeletal muscle fiber link

ketone body biosynthetic process link ↓ DECREASED gluconeogenesis link ↓ DECREASED

Downstream

Hypoketotic hypoglycemia Impaired FAO limits ketogenesis and fasting fuel supply, causing hypoketotic hypoglycemia.

Hepatic involvement Hepatic energy failure and lipid handling defects contribute to hepatopathy in severe infantile MTP deficiency.

Cardiomyopathy Cardiac reliance on long-chain fatty acid oxidation makes energetic insufficiency during stress a contributor to cardiomyopathy.

Rhabdomyolysis Skeletal-muscle energy deficit during exercise or illness predisposes to rhabdomyolysis.

Myalgia Stress-related muscle energy failure manifests as muscle pain in later-onset MTP deficiency.

Hypotonia Impaired mitochondrial energy production contributes to the myopathic spectrum that includes hypotonia.

Creatine kinase Rhabdomyolysis and myopathic crises elevate CK and CK-MB.

Respiratory failure Severe and intermediate MTP deficiency can progress to respiratory failure during systemic energy decompensation.

Lactic acidosis Severe neonatal MTP deficiency can present with lactic acidosis during systemic metabolic decompensation.

Sudden death Severe neonatal or infectious-triggered metabolic crises can be fatal.

Show evidence (1 reference)

PMID:29502916 SUPPORT Other

"Enzymatic defects in FAO and the carnitine shuttling pathway are associated with impaired energy production during times of increased demand."

Review evidence supports energy failure during fasting, illness, and physiologic stress.

Neurotoxicity from long-chain fatty acid metabolite accumulation

Peripheral neuropathy is a hallmark of MTP deficiency, particularly in later-onset forms. The neuromuscular system is the most commonly involved organ system. Axonal polyneuropathy, including sensory neuronopathy (ganglionopathy), is characteristic. In adult patients, sensory ataxia from sensory neuronopathy can be the predominant neurological feature. The neuropathy is thought to result from toxic effects of accumulated long-chain acyl-CoA and 3-hydroxy fatty acid intermediates on peripheral nerves.

fatty acid beta-oxidation link

Downstream

Peripheral neuropathy Toxic long-chain fatty-acid metabolite accumulation is associated with axonal neuropathy and sensory neuronopathy.

Distal muscle weakness Axonal polyneuropathy from HADHB-associated MTP deficiency manifests with distal weakness, areflexia, and foot deformities.

Show evidence (2 references)

PMID:34543737 SUPPORT Human Clinical

"Neuromuscular system is more vulnerable involved."

Confirms neuromuscular system as the most commonly affected organ system.

PMID:32253025 SUPPORT Human Clinical

"Peripheral nerve involvement manifesting as sensory ataxia appeared later, during adolescence or adulthood. In all cases, electroneuromyogram showed no length-dependent sensory potentials decrease characteristic of sensory neuronopathy"

Demonstrates sensory neuronopathy as a major adult neurological feature.

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Pathograph

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

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Phenotypes

Cardiovascular 1

Cardiomyopathy FREQUENT Cardiomyopathy (HP:0001638)

Show evidence (2 references)

PMID:31730477 SUPPORT Human Clinical

"Included studies suggested fewer heart and liver problems in screen-detected patients, but inconsistent results for mortality."

Supports cardiomyopathy as a significant MTP complication mitigated by early screening.

PMID:34543737 SUPPORT Human Clinical

"Severe form is generally characterized by multiorgan involvement."

Cardiomyopathy is part of the multiorgan involvement in severe MTP deficiency.

Endocrine 1

Hypoparathyroidism OCCASIONAL Hypoparathyroidism (HP:0000829)

Show evidence (1 reference)

PMID:34543737 SUPPORT Human Clinical

"Our case is a complete TFP deficiency patient dominated presented with hypoparathyroidism, neutropenia and nephrotic syndrome"

Supports hypoparathyroidism as a reported atypical presentation.

Eye 1

Retinopathy OCCASIONAL Pigmentary retinopathy (HP:0000580)

Show evidence (1 reference)

PMID:32253025 SUPPORT Human Clinical

"MTPD should be screened for by performing plasma acylcarnitines in patients with chronic sensory neuronopathy and additional suggestive features such as exercise intolerance or retinopathy."

Lists retinopathy among suggestive features of MTP deficiency.

Metabolism 2

Hypoketotic hypoglycemia FREQUENT Hypoketotic hypoglycemia (HP:0001985)

Show evidence (2 references)

PMID:35677112 SUPPORT Human Clinical

"many features including initial report of cardiomyopathy and hypoglycemia presented across a wide age spectrum."

Confirms hypoglycemia as a feature presenting across the age spectrum.

PMID:24314034 SUPPORT Human Clinical

"hepatic form with recurrent hypoketotic hypoglycemia"

Identifies hypoketotic hypoglycemia as a classical MTP/HADHB phenotype.

Lactic acidosis OCCASIONAL Lactic acidosis (HP:0003128)

Show evidence (1 reference)

PMID:19880769 SUPPORT Human Clinical

"Here, we report the case of a Korean male newborn who presented with severe lactic acidosis, seizures, and heart failure."

Case evidence supports lactic acidosis as a severe neonatal MTPD presentation.

Musculoskeletal 3

Rhabdomyolysis FREQUENT Rhabdomyolysis (HP:0003201)

Show evidence (1 reference)

PMID:32253025 SUPPORT Human Clinical

"Onset of the disease was characterized in all patients by rhabdomyolysis episodes occurring during childhood preceded by severe hypoglycemic episodes in three patients."

Characterizes rhabdomyolysis episodes occurring during childhood as the initial disease presentation in this cohort.

Hypotonia FREQUENT Hypotonia (HP:0001252)

Show evidence (1 reference)

PMID:35023662 SUPPORT Human Clinical

"Signs and symptoms of MTPD may present during infancy or later in life; those that begin after infancy include hypotonia, muscle pain, rhabdomyolysis, and peripheral neuropathy."

Directly lists hypotonia as a presenting symptom of MTP deficiency.

Distal muscle weakness FREQUENT Distal muscle weakness (HP:0002460)

Show evidence (2 references)

PMID:29956646 SUPPORT Human Clinical

"Both had delayed motor development and slowly-progressing distal muscle weakness with areflexia and foot deformities."

Directly describes distal muscle weakness as a presenting feature.

PMID:28132977 SUPPORT Human Clinical

"A 45-year-old man presented to us due to slowly progressive muscle weakness and sensory disturbances in his lower limbs since his 40's."

Confirms slowly progressive weakness in adult-onset MTP deficiency.

Nervous System 1

Peripheral neuropathy FREQUENT Peripheral neuropathy (HP:0009830)

Show evidence (2 references)

PMID:32253025 SUPPORT Human Clinical

"Peripheral nerve involvement manifesting as sensory ataxia appeared later, during adolescence or adulthood."

Characterizes peripheral neuropathy timing in adult MTP patients.

PMID:35023662 SUPPORT Human Clinical

"Electroneuromyography (ENMG) analysis showed moderate symmetric distal sensorimotor and axonal neuropathy."

Confirms electrophysiological pattern of axonal neuropathy in MTP deficiency.

Respiratory 1

Respiratory failure OCCASIONAL Respiratory failure (HP:0002878)

Show evidence (1 reference)

PMID:34543737 SUPPORT Human Clinical

"A notable feature of severe and intermediate form is respiratory failure."

Directly identifies respiratory failure as a notable feature of MTP deficiency.

Constitutional 2

Myalgia FREQUENT Myalgia (HP:0003326)

Show evidence (1 reference)

PMID:28132977 SUPPORT Human Clinical

"He reported multiple episodes of exercise-induced severe muscle fatigue and brown urine in his childhood"

Supports exercise-induced myopathy in MTP deficiency.

Sudden death OCCASIONAL Sudden death (HP:0001699)

Show evidence (2 references)

PMID:34543737 SUPPORT Human Clinical

"The mortality of the present study is as high as 57.9%, which is linked with the onset age, phenotype, mutation type and muscular histology."

Confirms high mortality rate in MTP deficiency from multiple causes including metabolic crises.

PMID:34878152 SUPPORT Human Clinical

"The two patients with MTPD experienced metabolic crises and died following an infectious disease."

Supports lethal metabolic crises in MTP deficiency.

Other 1

Hepatic involvement FREQUENT Abnormality of the liver (HP:0001392)

Show evidence (2 references)

PMID:29502916 SUPPORT Other

"Neonates and infants many present with sudden death, hepatopathy (Reye-like disease), hypoketotic hypoglycemia, rhabdomyolysis, myopathy, cardiomyopathy, and pulmonary edema."

Review evidence directly lists hepatopathy in neonatal and infant TFP deficiency.

PMID:31730477 SUPPORT Human Clinical

"Included studies suggested fewer heart and liver problems in screen-detected patients"

Clinical systematic-review evidence supports liver involvement as an MTP/LCHAD complication.

🧬

Genetic Associations

HADHA pathogenic variants causing MTP deficiency

Autosomal recessive

Show evidence (2 references)

PMID:34878152 SUPPORT Human Clinical

"metabolic disease of fatty acid oxidation. MTPD is an autosomal recessive disorder caused by mutations in the HADHA gene, encoding the α‑subunit of a trifunctional protease, or in the HADHB gene, encoding the β‑subunit of a trifunctional protease."

Directly supports HADHA mutations as one molecular cause of mitochondrial trifunctional protein deficiency.

PMID:34878152 SUPPORT Computational

"Molecular mechanistic analysis indicated that the two variants affected the conformation of the α‑subunit of the MTP enzyme complex, and consequently affected the stability and function of the enzyme complex."

Protein-structure modeling supports disruption of MTP complex stability and function by HADHA variants.

HADHB pathogenic variants causing MTP deficiency (Pathogenic Variants)

Autosomal recessive

Show evidence (4 references)

PMID:34878152 SUPPORT Human Clinical

Directly supports HADHB mutations as one molecular cause of mitochondrial trifunctional protein deficiency.

PMID:34543737 SUPPORT Human Clinical

"presentations. The type of mutation, rather than residual enzyme activity seem to be more related to the phenotype and prognosis."

Supports mutation type as a predictor of clinical phenotype.

PMID:34543737 SUPPORT Human Clinical

"mutation type and muscular histology. Mutations in HADHB are more frequent in Asian descent with complete TFP deficiency and usually presented with atypical presentations."

Supports the HADHB-associated molecular and clinical pattern in complete TFP deficiency.

+ 1 more reference

💊

Treatments

Dietary fat modification with MCT supplementation

Action: dietary intervention MAXO:0000088

The cornerstone of MTP deficiency management is restriction of long-chain dietary fat intake and supplementation with medium-chain triglycerides (MCT) which bypass the MTP-dependent step of beta-oxidation. Pre-symptomatic dietary management following newborn screening may be associated with a lower incidence of some complications.

Mechanism Target:

BYPASSES HADHA/HADHB molecular function deficiency in mitochondrial trifunctional protein — Medium-chain triglyceride supplementation supplies fatty acids that bypass the blocked long-chain MTP-dependent beta-oxidation steps.

Show evidence (1 reference)

PMID:29502916 SUPPORT Other

"Diet should be modified to decrease long-chain fat intake along with supplementation of the diet with MCT oil and essential fatty acids."

Review guidance supports reducing long-chain fat and supplementing MCT oil in TFP deficiency.

MODULATES Impaired energy production during catabolic stress — Lowering long-chain fat burden and using MCT oil reduces reliance on the impaired pathway during stress.

Show evidence (1 reference)

PMID:29502916 SUPPORT Other

"Diet should be modified to decrease long-chain fat intake along with supplementation of the diet with MCT oil and essential fatty acids."

Dietary modification is recommended to reduce metabolic stress from impaired long-chain FAO.

Show evidence (2 references)

PMID:31730477 SUPPORT Human Clinical

"There is some evidence that dietary management following screen-detection might be associated with a lower incidence of some LCHAD and MTP deficiency-related complications."

Supports dietary management as the primary treatment modality.

PMID:31730477 SUPPORT Human Clinical

"Without dietary management the conditions are life-threatening."

Emphasizes that dietary management is essential for survival.

Triheptanoin therapy

Action: nutritional supplementation MAXO:0000106

Agent: triheptanoin

Triheptanoin is an odd-chain triglyceride nutritional therapy for long-chain fatty acid oxidation disorders. It provides anaplerotic substrate while bypassing the impaired long-chain fatty acid oxidation pathway and is supported by LC-FAOD trial and cohort evidence.

Mechanism Target:

BYPASSES Impaired mitochondrial long-chain fatty acid beta-oxidation — Triheptanoin supplies medium odd-chain fatty acid calories that can support energy metabolism without relying on the blocked long-chain TFP-dependent beta-oxidation steps.

Show evidence (1 reference)

PMID:32840329 SUPPORT Other

"In recent years, the use of medium, odd-chain fatty acids, such as triheptanoin, have been studied as a treatment of LC-FAODs due to its anaplerotic properties."

Review evidence supports triheptanoin as an anaplerotic treatment strategy for long-chain fatty acid oxidation disorders.

MODULATES Impaired energy production during catabolic stress — Triheptanoin is intended to reduce catabolic decompensation episodes and support energy production in LC-FAOD.

Show evidence (1 reference)

DOI:10.1186/s13052-024-01782-y SUPPORT Human Clinical

"Triheptanoin was well tolerated and decreased the number of intercurrent catabolic episodes, metabolic decompensation episodes requiring hospitalisation, and the annualised rate and duration of hospitalisations."

Retrospective human cohort data support fewer catabolic and metabolic decompensation episodes during triheptanoin treatment.

Target Phenotypes: Cardiomyopathy ↗ Rhabdomyolysis ↗ Myalgia ↗

Show evidence (5 references)

PMID:32840329 SUPPORT Other

"Due to favorable safety and efficacy data from clinical trials, this novel agent has the potential to transform the treatment of LC-FAODs and improve patient outcomes in this patient population."

Clinical review evidence supports triheptanoin as a therapeutic option with favorable trial data in LC-FAOD.

clinicaltrials:NCT01379625 SUPPORT Human Clinical

"This study will determine if a new experimental oil called Triheptanoin can decrease the muscle pain and increase the heart function and the amount of energy in patients with long-chain fatty acid oxidation disorders."

Phase 2 trial record supports triheptanoin evaluation for muscle pain, cardiac function, and energy outcomes in LC-FAOD.

clinicaltrials:NCT01886378 SUPPORT Human Clinical

"The primary objective of the study was to evaluate the impact of UX007 on acute clinical pathophysiology associated with LC-FAOD following 24 weeks of treatment."

Phase 2 trial record supports UX007/triheptanoin evaluation against acute LC-FAOD clinical pathophysiology.

+ 2 more references

Avoidance of fasting and catabolic stress

Action: supportive care MAXO:0000950

Preventing prolonged fasting is critical. Frequent meals, cornstarch supplementation at night, and emergency protocols with IV glucose during illness help prevent metabolic decompensation.

Mechanism Target:

MODULATES Impaired energy production during catabolic stress — Avoiding fasting and illness-triggered catabolism reduces episodes when impaired FAO cannot meet energy demand.

Show evidence (1 reference)

PMID:29502916 SUPPORT Other

"Therapy is similar to VLCAD deficiency and includes avoiding the physiologic triggers of fasting and illness."

Review guidance supports avoiding fasting and illness triggers to reduce catabolic energy stress.

Show evidence (1 reference)

PMID:35023662 SUPPORT Human Clinical

"acute relapsing episodes triggered by fasting or illnesses"

Confirms fasting and illness as triggers for metabolic crises, supporting avoidance strategy.

Carnitine supplementation

Action: carnitine supplementation MAXO:0010006

Agent: carnitine ↗

Low-dose L-carnitine is a controversial supportive option in MTP deficiency, and high-dose intravenous carnitine during decompensation is not recommended.

Mechanism Target:

MODULATES Impaired mitochondrial long-chain fatty acid beta-oxidation — Low-dose carnitine is a conditional supportive intervention rather than correction of the TFP enzyme block.

Show evidence (1 reference)

PMID:29502916 SUPPORT Other

"Carnitine supplementation remains controversial, but low doses do not cause harm."

Review guidance supports only a cautious, low-dose role for carnitine in TFP deficiency.

Show evidence (1 reference)

PMID:29502916 SUPPORT Other

"Carnitine supplementation remains controversial, but low doses do not cause harm. Intravenous supplementation of carnitine in high doses during decompensation is not recommended."

Supports a cautious carnitine entry while preventing overstatement of routine high-dose use.

Bezafibrate therapy

Action: pharmacotherapy MAXO:0000058

Agent: bezafibrate ↗

Bezafibrate, a PPAR-alpha agonist, has been shown to upregulate MTP expression in control fibroblasts and improve fatty acid oxidation capacities in a subset (23%) of MTP-deficient patient cell lines, particularly those heterozygous for the common c.1528G>C mutation.

Mechanism Target:

MODULATES HADHA/HADHB molecular function deficiency in mitochondrial trifunctional protein — Bezafibrate can upregulate HADHA/HADHB expression and residual MTP activity in responsive fibroblast genotypes.

Show evidence (1 reference)

PMID:26109258 SUPPORT In Vitro

"activities of LCHAD and LCKAT, and stimulated FAO capacities, clearly indicating that MTP is pharmacologically up-regulated by bezafibrate in human fibroblasts."

Human fibroblast evidence supports bezafibrate as a pharmacologic modulator of residual MTP function.

Show evidence (1 reference)

PMID:26109258 SUPPORT In Vitro

"MTP is pharmacologically up-regulated by bezafibrate in human fibroblasts."

Confirms pharmacological upregulation of MTP by bezafibrate.

Newborn screening

Action: disease screening MAXO:0000124

MTP deficiency can be detected by newborn screening using tandem mass spectrometry to identify elevated long-chain 3-hydroxyacylcarnitines. Screen detection may be associated with fewer cardiac and hepatic complications, though mitigated phenotypes can be missed by screening.

Target Phenotypes: Cardiomyopathy ↗ Hepatic involvement ↗

Show evidence (2 references)

PMID:31730477 SUPPORT Human Clinical

"Included studies suggested fewer heart and liver problems in screen-detected patients, but inconsistent results for mortality."

Supports newborn screening benefit for reducing cardiac and hepatic complications.

PMID:30682426 SUPPORT Human Clinical

"The mitigated phenotypes of this treatable disease were missed by the newborn screening, highlighting the importance of phenotype-based NGS analysis"

Notes that milder MTP phenotypes may be missed by standard newborn screening.

Genetic counseling

Action: genetic counseling MAXO:0000079

Genetic counseling for affected families including discussion of autosomal recessive inheritance, 25% recurrence risk, carrier testing, and prenatal diagnosis options. Maternal complications including HELLP syndrome and acute fatty liver of pregnancy may occur in pregnancies carrying affected fetuses.

Mechanism Target:

MODULATES HADHA/HADHB molecular function deficiency in mitochondrial trifunctional protein — Counseling addresses the autosomal recessive HADHA/HADHB molecular cause, recurrence risk, carrier testing, and prenatal diagnosis rather than directly changing metabolism.

Show evidence (1 reference)

PMID:34878152 SUPPORT Human Clinical

Human family evidence supports genetics-informed counseling around the biallelic HADHA/HADHB cause.

Show evidence (2 references)

PMID:28515471 SUPPORT Human Clinical

"Maternal hemolysis, elevated liver enzymes and low platelet count syndrome and acute fatty liver of pregnancy were noted in two and one mothers, respectively."

Maternal complications necessitate genetic counseling and pregnancy monitoring.

PMID:34878152 SUPPORT Human Clinical

"Using amniotic fluid prenatal diagnostic testing, the unborn child was confirmed to carry only c.2107G>A (p.G703R)."

Demonstrates availability and utility of prenatal diagnosis for MTP deficiency.

Acute crisis management

Action: supportive care MAXO:0000950

Emergency management of metabolic decompensation episodes includes intravenous glucose to suppress catabolism, correction of metabolic acidosis, monitoring for cardiac arrhythmias, and management of rhabdomyolysis with aggressive hydration.

Mechanism Target:

MODULATES Impaired energy production during catabolic stress — Acute glucose support suppresses catabolism and provides carbohydrate fuel when long-chain FAO cannot meet energy demand.

Show evidence (1 reference)

PMID:39203843 SUPPORT Other

"The main measure in emergency hospital treatment is the administration of IV glucose."

FAOD nutritional guidance supports IV glucose as the emergency measure to suppress catabolism.

Show evidence (1 reference)

PMID:34878152 SUPPORT Human Clinical

"The two patients with MTPD experienced metabolic crises and died following an infectious disease."

Metabolic crises during infectious illness underscore need for aggressive crisis management.

Physical therapy and rehabilitation

Action: physical therapy MAXO:0000011

Physical therapy for patients with peripheral neuropathy and myopathy to maintain mobility, prevent contractures, and manage distal muscle weakness and foot deformities.

Target Phenotypes: Peripheral neuropathy ↗ Distal muscle weakness ↗

Show evidence (2 references)

PMID:29956646 SUPPORT Human Clinical

"Both had delayed motor development and slowly-progressing distal muscle weakness with areflexia and foot deformities."

Distal weakness and foot deformities support need for physical therapy and rehabilitation.

PMID:29956646 SUPPORT Human Clinical

"The electrophysiology findings were compatible with axonal polyneuropathy in both patients."

Axonal polyneuropathy supports rehabilitation-focused management of neuropathic functional impairment.

🌍

Environmental Factors

Fasting

Prolonged fasting is a major trigger for metabolic decompensation in MTP deficiency, as the body cannot effectively oxidize long-chain fatty acids for energy during periods of caloric deprivation.

Show evidence (1 reference)

PMID:35023662 SUPPORT Human Clinical

"acute relapsing episodes triggered by fasting or illnesses"

Confirms fasting as a trigger for acute episodes.

Intercurrent illness

Febrile illness and infections increase metabolic demands and promote catabolism, triggering decompensation episodes including rhabdomyolysis and hypoglycemia.

Show evidence (1 reference)

PMID:34878152 SUPPORT Human Clinical

"The two patients with MTPD experienced metabolic crises and died following an infectious disease."

Directly demonstrates infectious disease as a fatal trigger.

Prolonged exercise

Intense or prolonged physical exercise can precipitate rhabdomyolysis and muscle breakdown in MTP deficiency due to reliance on fatty acid oxidation for sustained muscle energy.

Show evidence (1 reference)

PMID:28132977 SUPPORT Human Clinical

"He reported multiple episodes of exercise-induced severe muscle fatigue and brown urine in his childhood"

Confirms exercise as a trigger for myoglobinuria episodes.

🔬

Biochemical Markers

Long-chain 3-hydroxyacylcarnitines (C16-OH, C18:1-OH) (INCREASED)

Context: Elevated long-chain 3-hydroxyacylcarnitines, particularly C16-OH and C18:1-OH, are the most common biochemical finding in MTP deficiency and serve as the primary diagnostic markers on newborn screening and acylcarnitine profiling.

Pathograph Readouts

Readout Of Impaired mitochondrial long-chain fatty acid beta-oxidation Positive Diagnostic

Elevated C16-OH and C18:1-OH report the blocked long-chain TFP-dependent beta-oxidation steps.

Show evidence (1 reference)

PMID:34543737 SUPPORT Human Clinical

"Increased long-chain 3-OH-acylcarnitines (C16-OH, C18:1-OH) are the most common biochemical finding."

Directly identifies elevated C16-OH and C18:1-OH acylcarnitines as the most common biochemical finding.

Long-chain acylcarnitines (INCREASED)

Context: Broadly elevated long-chain acylcarnitines are detectable by tandem mass spectrometry in blood samples from MTP-deficient patients. This includes multiple species reflecting impaired beta-oxidation of long-chain fatty acids.

Pathograph Readouts

Readout Of Impaired mitochondrial long-chain fatty acid beta-oxidation Positive Diagnostic

Elevated long-chain acylcarnitines report impaired long-chain fatty acid oxidation flux.

Show evidence (2 references)

PMID:32253025 SUPPORT Human Clinical

"MTPD should be screened for by performing plasma acylcarnitines in patients with chronic sensory neuronopathy"

Supports acylcarnitine profiling as a diagnostic tool for MTP deficiency.

PMID:34878152 SUPPORT Human Clinical

"Tandem mass spectrometry revealed that long‑chain acyl‑carnitine was markedly elevated in blood samples from the patients with MTPD."

Patient data directly support elevation of long-chain acylcarnitines.

Creatine kinase (INCREASED)

Context: Creatine kinase (CK) and CK-MB are elevated during rhabdomyolysis episodes and may be chronically elevated in patients with myopathic involvement.

Pathograph Readouts

Readout Of Rhabdomyolysis Positive Monitoring

Increased CK reports muscle breakdown during rhabdomyolysis or myopathic crises.

Show evidence (1 reference)

PMID:34878152 SUPPORT Human Clinical

"Lactate dehydrogenase, creatine kinase (CK), CK‑MB and liver enzyme abnormalities were observed in routine examinations."

Patient data support elevated CK and CK-MB in MTP deficiency.

Hepatic lipid accumulation (PRESENT)

Context: Fat accumulation in the liver and heart can be demonstrated on autopsy or biopsy, reflecting impaired fatty acid oxidation and lipid storage.

Pathograph Readouts

Readout Of Impaired mitochondrial long-chain fatty acid beta-oxidation Present Absent Diagnostic

Tissue lipid accumulation reports failure to oxidize fatty acids in affected organs.

Show evidence (1 reference)

PMID:34878152 SUPPORT Human Clinical

"The autopsy results for one child revealed fat accumulation in the liver and heart."

Directly demonstrates hepatic and cardiac lipid accumulation on autopsy.

Long-chain 3-hydroxy fatty acids (INCREASED)

Context: Long-chain 3-hydroxy fatty acids accumulate when MTP/LCHAD-dependent beta-oxidation steps are blocked, and these intermediates can uncouple cardiac oxidative phosphorylation.

Pathograph Readouts

Readout Of Uncoupling of cardiac oxidative phosphorylation by long-chain 3-hydroxy fatty acids Positive Diagnostic

Accumulated long-chain 3-hydroxy fatty acids report the toxic intermediary pool implicated in oxidative-phosphorylation uncoupling.

Show evidence (1 reference)

PMID:23065309 SUPPORT In Vitro

"The present data indicate that major 3-hydroxylated fatty acids accumulating in MTP and LCHAD deficiencies behave as strong uncouplers of oxidative phosphorylation potentially impairing heart energy homeostasis."

In vitro heart mitochondria data support accumulation and toxicity of long-chain 3-hydroxy fatty acids.

{ }

Source YAML

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name: Mitochondrial Trifunctional Protein Deficiency
category: Mendelian
creation_date: '2026-02-23T00:00:00Z'
updated_date: '2026-05-18T19:59:26Z'
synonyms:
- MTP deficiency
- MTPD
- Trifunctional protein deficiency
- TFP deficiency
- Complete TFP deficiency
description: 'Mitochondrial trifunctional protein (MTP) deficiency is a rare autosomal recessive disorder of mitochondrial long-chain fatty acid beta-oxidation caused by biallelic pathogenic variants in HADHA (encoding the alpha subunit) or HADHB (encoding the beta subunit) of the heterooctameric mitochondrial trifunctional protein complex. MTP harbors three enzymatic activities: long-chain enoyl-CoA hydratase, long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD), and long-chain 3-ketoacyl-CoA thiolase (LCKAT). Complete deficiency of all three activities results in MTP deficiency, which is clinically heterogeneous, ranging from severe neonatal presentations with cardiomyopathy, hypoglycemia, and early death, to milder later-onset forms with peripheral neuropathy and episodic rhabdomyolysis. The mortality is high, reported as 57.9% in a large retrospective analysis. HADHB mutations are more frequent in Asian populations and are associated with atypical presentations. Maternal HELLP syndrome and acute fatty liver of pregnancy may be associated with pregnancies carrying affected fetuses.

  '
disease_term:
  preferred_term: mitochondrial trifunctional protein deficiency
  term:
    id: MONDO:0012172
    label: mitochondrial trifunctional protein deficiency
classifications:
  harrisons_chapter:
  - classification_value: hereditary disease
  - classification_value: cardiovascular disorder
  mechanistic_category:
  - classification_value: mitochondrial disease
parents:
- Fatty Acid Oxidation Disorder
- Inborn Error of Metabolism
prevalence:
- notes: 'MTP deficiency is extremely rare. In a systematic review, only 18 patients with confirmed MTP deficiency and 174 with LCHAD deficiency were identified across 13 published studies.

    '
  evidence:
  - reference: PMID:31730477
    reference_title: "Evaluation of earlier versus later dietary management in long-chain 3-hydroxyacyl-CoA dehydrogenase or mitochondrial trifunctional protein deficiency: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: including 174 people with LCHAD deficiency, 18 people with MTP deficiency and 12 people with undifferentiated LCHAD/MTP deficiency.
    explanation: Quantifies the rarity of confirmed MTP deficiency in published literature.
progression:
- notes: 'Disease progression varies by clinical subtype. Severe neonatal-onset forms present within the first days to weeks of life with multiorgan failure and high mortality. Intermediate forms present in infancy or early childhood with hepatic and cardiac involvement. Late-onset or mild forms manifest in childhood or adulthood with progressive peripheral neuropathy and episodic rhabdomyolysis. Retinopathy, rhabdomyolysis, and peripheral neuropathy tend to present later in childhood, while cardiomyopathy and hypoglycemia can present across a wide age spectrum.

    '
  evidence:
  - reference: PMID:35677112
    reference_title: "Outcomes and genotype correlations in patients with mitochondrial trifunctional protein or isolated long chain 3-hydroxyacyl-CoA dehydrogenase deficiency enrolled in the IBEM-IS database."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: retinopathy, rhabdomyolysis and peripheral neuropathy tended to present later in childhood, many features including initial report of cardiomyopathy and hypoglycemia presented across a wide age spectrum.
    explanation: Supports age-dependent progression pattern of different complications.
has_subtypes:
- name: Severe neonatal form
  description: 'Presents in the first days to weeks of life with cardiomyopathy, hypoglycemia, hepatic dysfunction, and multiorgan failure. High mortality. Generally characterized by multiorgan involvement.

    '
- name: Infantile hepatic form
  description: 'Presents in infancy with hypoketotic hypoglycemia, hepatomegaly, and hepatic dysfunction. May include cardiomyopathy.

    '
- name: Late-onset myopathic form
  description: 'Presents in childhood or adulthood with progressive peripheral neuropathy, episodic rhabdomyolysis, exercise intolerance, and possible retinopathy. More commonly associated with HADHB mutations.

    '
pathophysiology:
- name: HADHA/HADHB molecular function deficiency in mitochondrial trifunctional protein
  description: 'Biallelic pathogenic variants in HADHA or HADHB reduce catalytic activities of the mitochondrial trifunctional protein complex.

    '
  genes:
  - preferred_term: HADHA
    term:
      id: hgnc:4801
      label: HADHA
  - preferred_term: HADHB
    term:
      id: hgnc:4803
      label: HADHB
  molecular_functions:
  - preferred_term: enoyl-CoA hydratase activity
    term:
      id: GO:0004300
      label: enoyl-CoA hydratase activity
    modifier: DECREASED
  - preferred_term: long-chain 3-hydroxyacyl-CoA dehydrogenase activity
    term:
      id: GO:0003857
      label: (3S)-3-hydroxyacyl-CoA dehydrogenase (NAD+) activity
    modifier: DECREASED
  - preferred_term: 3-ketoacyl-CoA thiolase activity
    term:
      id: GO:0003988
      label: acetyl-CoA C-acyltransferase activity
    modifier: DECREASED
  biological_processes:
  - preferred_term: fatty acid beta-oxidation
    term:
      id: GO:0006635
      label: fatty acid beta-oxidation
    modifier: DECREASED
  locations:
  - preferred_term: mitochondrial inner membrane
    term:
      id: GO:0005743
      label: mitochondrial inner membrane
  evidence:
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Mitochondrial trifunctional protein (TFP) deficiency is an autosomal recessive disorder that causes a clinical spectrum of diseases ranging from severe infantile cardiomyopathy to mild chronic progressive neuromyopathy
    explanation: Supports proximal molecular dysfunction of TFP encoded by HADHA/HADHB.
  downstream:
  - target: Impaired mitochondrial long-chain fatty acid beta-oxidation
    description: Reduced TFP catalytic function limits sequential long-chain FAO reactions.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "TFP enzyme activities include 2-enoyl-CoA hydratase, LCHAD, and 3-ketoacyl-CoA thiolase."
      explanation: Review evidence identifies the three TFP enzyme activities whose deficiency blocks long-chain fatty acid oxidation.
- name: Impaired mitochondrial long-chain fatty acid beta-oxidation
  description: 'The mitochondrial trifunctional protein is a heterooctamer (alpha4-beta4) on the inner mitochondrial membrane that catalyzes three sequential steps of long-chain fatty acid beta-oxidation. Deficiency impairs long-chain FAO, causing stress-dependent energy failure and accumulation of toxic long-chain acylcarnitine intermediates.

    '
  biological_processes:
  - preferred_term: fatty acid beta-oxidation
    term:
      id: GO:0006635
      label: fatty acid beta-oxidation
    modifier: DECREASED
  - preferred_term: long-chain fatty acid metabolic process
    term:
      id: GO:0001676
      label: long-chain fatty acid metabolic process
    modifier: DECREASED
  locations:
  - preferred_term: mitochondrial inner membrane
    term:
      id: GO:0005743
      label: mitochondrial inner membrane
  cell_types:
  - preferred_term: hepatocyte
    term:
      id: CL:0000182
      label: hepatocyte
  - preferred_term: cardiac muscle cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  - preferred_term: skeletal muscle fiber
    term:
      id: CL:0008002
      label: skeletal muscle fiber
  evidence:
  - reference: PMID:29502916
    reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The subsequent 3 steps for long-chain substrates are catalyzed by trifunctional protein (TFP), a heterooctomer encompassing all 3 remaining enzymatic activities."
    explanation: Supports TFP as the enzyme complex required for long-chain fatty acid beta-oxidation.
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Mitochondrial trifunctional protein (TFP) deficiency is an autosomal recessive disorder that causes a clinical spectrum of diseases ranging from severe infantile cardiomyopathy to mild chronic progressive neuromyopathy
    explanation: Supports impaired long-chain FAO and downstream tissue injury in MTP deficiency.
  downstream:
  - target: Uncoupling of cardiac oxidative phosphorylation by long-chain 3-hydroxy fatty acids
    description: Blocked long-chain FAO causes accumulation of long-chain 3-hydroxy fatty acids that impair mitochondrial oxidative phosphorylation.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23065309
      reference_title: "Long-chain 3-hydroxy fatty acids accumulating in long-chain 3-hydroxyacyl-CoA dehydrogenase and mitochondrial trifunctional protein deficiencies uncouple oxidative phosphorylation in heart mitochondria."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "The present data indicate that major 3-hydroxylated fatty acids accumulating in MTP and LCHAD deficiencies behave as strong uncouplers of oxidative phosphorylation potentially impairing heart energy homeostasis."
      explanation: In vitro heart mitochondrial data support toxic 3-hydroxy fatty acid accumulation downstream of MTP/LCHAD deficiency.
  - target: Impaired energy production during catabolic stress
    description: Loss of long-chain FAO limits ATP production when tissues rely on fatty acids during fasting, illness, or sustained exercise.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Enzymatic defects in FAO and the carnitine shuttling pathway are associated with impaired energy production during times of increased demand."
      explanation: Review evidence supports stress-related energy failure downstream of fatty acid oxidation defects.
  - target: Long-chain 3-hydroxyacylcarnitines (C16-OH, C18:1-OH)
    description: Impaired TFP-dependent oxidation produces elevated long-chain hydroxyacylcarnitines used in newborn screening and biochemical diagnosis.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:34543737
      reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Increased long-chain 3-OH-acylcarnitines (C16-OH, C18:1-OH) are the most common biochemical finding."
      explanation: Clinical review evidence identifies increased C16-OH and C18:1-OH as the most common biochemical consequence.
  - target: Long-chain acylcarnitines
    description: Impaired long-chain FAO leads to elevated long-chain acylcarnitines on tandem mass spectrometry.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:34878152
      reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Tandem mass spectrometry revealed that long‑chain acyl‑carnitine was markedly elevated in blood samples from the patients with MTPD."
      explanation: Patient data support long-chain acylcarnitine elevation downstream of MTP deficiency.
  - target: Hepatic lipid accumulation
    description: Failure to oxidize fatty acids causes lipid accumulation in liver and heart.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:34878152
      reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The autopsy results for one child revealed fat accumulation in the liver and heart."
      explanation: Autopsy evidence supports tissue lipid accumulation downstream of impaired fatty acid oxidation.
  - target: Long-chain 3-hydroxy fatty acids
    description: Incomplete long-chain fatty acid beta-oxidation causes accumulation of hydroxylated long-chain fatty acids.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23065309
      reference_title: "Long-chain 3-hydroxy fatty acids accumulating in long-chain 3-hydroxyacyl-CoA dehydrogenase and mitochondrial trifunctional protein deficiencies uncouple oxidative phosphorylation in heart mitochondria."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "The present data indicate that major 3-hydroxylated fatty acids accumulating in MTP and LCHAD deficiencies behave as strong uncouplers of oxidative phosphorylation potentially impairing heart energy homeostasis."
      explanation: In vitro evidence supports accumulation of major 3-hydroxylated fatty acids in MTP/LCHAD deficiency.
  - target: Hypoparathyroidism
    description: Complete TFP deficiency can include atypical parathyroid involvement, although the intervening mechanism is not defined.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:34543737
      reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Our case is a complete TFP deficiency patient dominated presented with hypoparathyroidism, neutropenia and nephrotic syndrome
      explanation: Case-level human evidence associates complete TFP deficiency with hypoparathyroidism; the causal intermediates remain unresolved.
- name: Uncoupling of cardiac oxidative phosphorylation by long-chain 3-hydroxy fatty acids
  description: 'Long-chain 3-hydroxy fatty acids that accumulate in MTP deficiency (3-hydroxytetradecanoic acid, 3-hydroxypalmitic acid) act as potent uncouplers of oxidative phosphorylation in heart mitochondria. They increase resting respiration, diminish the respiratory control ratio, decrease mitochondrial membrane potential, and can induce mitochondrial permeability transition pore opening in calcium-loaded organelles. This mechanism contributes to the cardiomyopathy and energy failure seen in MTP deficiency.

    '
  biological_processes:
  - preferred_term: oxidative phosphorylation
    term:
      id: GO:0006119
      label: oxidative phosphorylation
    modifier: DECREASED
  cell_types:
  - preferred_term: cardiac muscle cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  locations:
  - preferred_term: heart
    term:
      id: UBERON:0000948
      label: heart
  evidence:
  - reference: PMID:23065309
    reference_title: "Long-chain 3-hydroxy fatty acids accumulating in long-chain 3-hydroxyacyl-CoA dehydrogenase and mitochondrial trifunctional protein deficiencies uncouple oxidative phosphorylation in heart mitochondria."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: 3 HTA and 3 HPA increased resting respiration and diminished the respiratory control and ADP/O ratios using glutamate/malate or succinate as substrates.
    explanation: Confirms uncoupling effects of specific 3-hydroxy fatty acids on mitochondrial respiration.
  downstream:
  - target: Impaired energy production during catabolic stress
    description: Uncoupling of oxidative phosphorylation worsens ATP shortage during catabolic stress.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Mitochondrial oxidative phosphorylation uncoupling
    evidence:
    - reference: PMID:23065309
      reference_title: "Long-chain 3-hydroxy fatty acids accumulating in long-chain 3-hydroxyacyl-CoA dehydrogenase and mitochondrial trifunctional protein deficiencies uncouple oxidative phosphorylation in heart mitochondria."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "The present data indicate that major 3-hydroxylated fatty acids accumulating in MTP and LCHAD deficiencies behave as strong uncouplers of oxidative phosphorylation potentially impairing heart energy homeostasis."
      explanation: Toxic long-chain 3-hydroxy fatty acids can impair heart mitochondrial energy homeostasis.
  - target: Cardiomyopathy
    description: Long-chain 3-hydroxy fatty acids uncouple cardiac mitochondrial oxidative phosphorylation, contributing to cardiomyopathy.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Cardiac oxidative phosphorylation uncoupling
    - Impaired heart energy homeostasis
    evidence:
    - reference: PMID:23065309
      reference_title: "Long-chain 3-hydroxy fatty acids accumulating in long-chain 3-hydroxyacyl-CoA dehydrogenase and mitochondrial trifunctional protein deficiencies uncouple oxidative phosphorylation in heart mitochondria."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "Cardiomyopathy is a common clinical feature of some inherited disorders of mitochondrial fatty acid β-oxidation including mitochondrial trifunctional protein (MTP) and isolated long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiencies."
      explanation: The same mechanistic study frames cardiomyopathy as a common clinical feature of MTP/LCHAD deficiency.
  - target: Neurotoxicity from long-chain fatty acid metabolite accumulation
    description: Chronic accumulation of long-chain fatty-acid intermediates is linked to later neuromuscular complications.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Long-term complications, such as cardiomyopathy, peripheral neuropathy, and pigmentary retinopathy, and retinal degeneration leading to progressive visual loss also occur."
      explanation: Review evidence supports chronic neurologic and retinal complications downstream of TFP deficiency.
  - target: Retinopathy
    description: Chronic TFP/LCHAD-related fatty acid oxidation toxicity is associated with pigmentary retinopathy and retinal degeneration.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Long-term complications, such as cardiomyopathy, peripheral neuropathy, and pigmentary retinopathy, and retinal degeneration leading to progressive visual loss also occur."
      explanation: Review evidence supports retinopathy as a long-term complication of TFP deficiency.
- name: Impaired energy production during catabolic stress
  description: 'During fasting, illness, or prolonged exercise, the body relies heavily on long-chain fatty acid oxidation for energy. In MTP deficiency, this metabolic pathway is blocked, leading to hypoketotic hypoglycemia because both hepatic gluconeogenesis and ketogenesis are impaired. The inability to generate adequate ketone bodies as an alternative fuel for brain and heart during fasting contributes to metabolic decompensation, which can be life-threatening.

    '
  biological_processes:
  - preferred_term: ketone body biosynthetic process
    term:
      id: GO:0046951
      label: ketone body biosynthetic process
    modifier: DECREASED
  - preferred_term: gluconeogenesis
    term:
      id: GO:0006094
      label: gluconeogenesis
    modifier: DECREASED
  cell_types:
  - preferred_term: hepatocyte
    term:
      id: CL:0000182
      label: hepatocyte
  - preferred_term: cardiac muscle cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  - preferred_term: skeletal muscle fiber
    term:
      id: CL:0008002
      label: skeletal muscle fiber
  evidence:
  - reference: PMID:29502916
    reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Enzymatic defects in FAO and the carnitine shuttling pathway are associated with impaired energy production during times of increased demand."
    explanation: Review evidence supports energy failure during fasting, illness, and physiologic stress.
  downstream:
  - target: Hypoketotic hypoglycemia
    description: Impaired FAO limits ketogenesis and fasting fuel supply, causing hypoketotic hypoglycemia.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Neonates and infants many present with sudden death, hepatopathy (Reye-like disease), hypoketotic hypoglycemia, rhabdomyolysis, myopathy, cardiomyopathy, and pulmonary edema."
      explanation: Review evidence directly lists hypoketotic hypoglycemia in TFP deficiency.
  - target: Hepatic involvement
    description: Hepatic energy failure and lipid handling defects contribute to hepatopathy in severe infantile MTP deficiency.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Neonates and infants many present with sudden death, hepatopathy (Reye-like disease), hypoketotic hypoglycemia, rhabdomyolysis, myopathy, cardiomyopathy, and pulmonary edema."
      explanation: Review evidence supports hepatopathy as part of neonatal/infant TFP deficiency.
  - target: Cardiomyopathy
    description: Cardiac reliance on long-chain fatty acid oxidation makes energetic insufficiency during stress a contributor to cardiomyopathy.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Cardiac ATP shortage during physiologic stress
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Insufficient fuel reserves are associated with the risk of developing cardiomyopathy and/or rhabdomyolysis during periods of physiologic stress and illness."
      explanation: Review evidence links impaired energy reserves during stress to cardiomyopathy risk.
  - target: Rhabdomyolysis
    description: Skeletal-muscle energy deficit during exercise or illness predisposes to rhabdomyolysis.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Exercise- or illness-triggered skeletal muscle energy failure
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Long-chain FAODs, including CPT2 deficiency, VLCAD deficiency, long-chain hydroxyacyl-CoA dehydrogenases (LCHAD) deficiency and TFP deficiency, and glycogen metabolism disorders, including glycogen storage diseases (GSDs) types V, VII, and IXd, are associated with an increased risk of rhabdomyolysis induced by exercise."
      explanation: Review evidence supports exercise-induced rhabdomyolysis risk in TFP deficiency.
  - target: Myalgia
    description: Stress-related muscle energy failure manifests as muscle pain in later-onset MTP deficiency.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:35023662
      reference_title: "Mitochondrial trifunctional protein deficiency as a polyneuropathy etiology in childhood."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Signs and symptoms of MTPD may present during infancy or later in life; those that begin after infancy include hypotonia, muscle pain, rhabdomyolysis, and peripheral neuropathy."
      explanation: Clinical case evidence supports muscle pain as part of the MTPD neuromuscular phenotype.
  - target: Hypotonia
    description: Impaired mitochondrial energy production contributes to the myopathic spectrum that includes hypotonia.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:35023662
      reference_title: "Mitochondrial trifunctional protein deficiency as a polyneuropathy etiology in childhood."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Signs and symptoms of MTPD may present during infancy or later in life; those that begin after infancy include hypotonia, muscle pain, rhabdomyolysis, and peripheral neuropathy."
      explanation: Clinical case evidence directly lists hypotonia in MTPD.
  - target: Creatine kinase
    description: Rhabdomyolysis and myopathic crises elevate CK and CK-MB.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Rhabdomyolysis
    evidence:
    - reference: PMID:34878152
      reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Lactate dehydrogenase, creatine kinase (CK), CK‑MB and liver enzyme abnormalities were observed in routine examinations."
      explanation: Patient data support CK elevation during MTP deficiency crises.
  - target: Respiratory failure
    description: Severe and intermediate MTP deficiency can progress to respiratory failure during systemic energy decompensation.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:34543737
      reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "A notable feature of severe and intermediate form is respiratory failure."
      explanation: Clinical review evidence directly identifies respiratory failure in severe/intermediate TFP deficiency.
  - target: Lactic acidosis
    description: Severe neonatal MTP deficiency can present with lactic acidosis during systemic metabolic decompensation.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Systemic metabolic decompensation
    evidence:
    - reference: PMID:19880769
      reference_title: "Two novel HADHB gene mutations in a Korean patient with mitochondrial trifunctional protein deficiency."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Here, we report the case of a Korean male newborn who presented with severe lactic acidosis, seizures, and heart failure."
      explanation: Newborn case evidence supports severe lactic acidosis during MTPD presentation.
  - target: Sudden death
    description: Severe neonatal or infectious-triggered metabolic crises can be fatal.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Metabolic crisis
    - Multiorgan decompensation
    evidence:
    - reference: PMID:34878152
      reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The two patients with MTPD experienced metabolic crises and died following an infectious disease."
      explanation: Family report evidence supports fatal metabolic crises in MTP deficiency.
- name: Neurotoxicity from long-chain fatty acid metabolite accumulation
  description: 'Peripheral neuropathy is a hallmark of MTP deficiency, particularly in later-onset forms. The neuromuscular system is the most commonly involved organ system. Axonal polyneuropathy, including sensory neuronopathy (ganglionopathy), is characteristic. In adult patients, sensory ataxia from sensory neuronopathy can be the predominant neurological feature. The neuropathy is thought to result from toxic effects of accumulated long-chain acyl-CoA and 3-hydroxy fatty acid intermediates on peripheral nerves.

    '
  biological_processes:
  - preferred_term: fatty acid beta-oxidation
    term:
      id: GO:0006635
      label: fatty acid beta-oxidation
  evidence:
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Neuromuscular system is more vulnerable involved.
    explanation: Confirms neuromuscular system as the most commonly affected organ system.
  - reference: PMID:32253025
    reference_title: "Sensory neuronopathy as a major clinical feature of mitochondrial trifunctional protein deficiency in adults."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Peripheral nerve involvement manifesting as sensory ataxia appeared later, during adolescence or adulthood. In all cases, electroneuromyogram showed no length-dependent sensory potentials decrease characteristic of sensory neuronopathy
    explanation: Demonstrates sensory neuronopathy as a major adult neurological feature.
  downstream:
  - target: Peripheral neuropathy
    description: Toxic long-chain fatty-acid metabolite accumulation is associated with axonal neuropathy and sensory neuronopathy.
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:32253025
      reference_title: "Sensory neuronopathy as a major clinical feature of mitochondrial trifunctional protein deficiency in adults."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Peripheral nerve involvement manifesting as sensory ataxia appeared later, during adolescence or adulthood."
      explanation: Adult cohort evidence supports peripheral nerve involvement downstream of MTP deficiency.
  - target: Distal muscle weakness
    description: Axonal polyneuropathy from HADHB-associated MTP deficiency manifests with distal weakness, areflexia, and foot deformities.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Axonal polyneuropathy
    evidence:
    - reference: PMID:29956646
      reference_title: "HADHB mutations cause infantile-onset axonal Charcot-Marie-tooth disease: A report of two cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Both had delayed motor development and slowly-progressing distal muscle weakness with areflexia and foot deformities."
      explanation: HADHB case evidence supports distal weakness as a neuropathic manifestation.
phenotypes:
- name: Cardiomyopathy
  frequency: FREQUENT
  description: 'Cardiomyopathy is a common and often severe manifestation of MTP deficiency, particularly in neonatal-onset and infantile forms. Included studies suggested fewer heart problems in screen-detected patients compared to clinically diagnosed ones.

    '
  phenotype_term:
    preferred_term: Cardiomyopathy
    term:
      id: HP:0001638
      label: Cardiomyopathy
  evidence:
  - reference: PMID:31730477
    reference_title: "Evaluation of earlier versus later dietary management in long-chain 3-hydroxyacyl-CoA dehydrogenase or mitochondrial trifunctional protein deficiency: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Included studies suggested fewer heart and liver problems in screen-detected patients, but inconsistent results for mortality.
    explanation: Supports cardiomyopathy as a significant MTP complication mitigated by early screening.
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Severe form is generally characterized by multiorgan involvement.
    explanation: Cardiomyopathy is part of the multiorgan involvement in severe MTP deficiency.
- name: Hypoketotic hypoglycemia
  frequency: FREQUENT
  description: 'Hypoketotic hypoglycemia is a hallmark metabolic feature of MTP deficiency, reflecting impaired hepatic fatty acid oxidation and ketogenesis during fasting. Hypoglycemia can present across a wide age spectrum.

    '
  phenotype_term:
    preferred_term: Hypoketotic hypoglycemia
    term:
      id: HP:0001985
      label: Hypoketotic hypoglycemia
  evidence:
  - reference: PMID:35677112
    reference_title: "Outcomes and genotype correlations in patients with mitochondrial trifunctional protein or isolated long chain 3-hydroxyacyl-CoA dehydrogenase deficiency enrolled in the IBEM-IS database."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: many features including initial report of cardiomyopathy and hypoglycemia presented across a wide age spectrum.
    explanation: Confirms hypoglycemia as a feature presenting across the age spectrum.
  - reference: PMID:24314034
    reference_title: "A compound heterozygous mutation in HADHB gene causes an axonal Charcot-Marie-tooth disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: hepatic form with recurrent hypoketotic hypoglycemia
    explanation: Identifies hypoketotic hypoglycemia as a classical MTP/HADHB phenotype.
- name: Peripheral neuropathy
  frequency: FREQUENT
  description: 'Peripheral neuropathy is a typical manifestation especially in milder, later-onset forms of MTP deficiency. It presents as axonal sensorimotor neuropathy and can mimic Charcot-Marie-Tooth disease. In adults, sensory neuronopathy (ganglionopathy) with sensory ataxia can be the predominant feature.

    '
  phenotype_term:
    preferred_term: Peripheral neuropathy
    term:
      id: HP:0009830
      label: Peripheral neuropathy
  evidence:
  - reference: PMID:32253025
    reference_title: "Sensory neuronopathy as a major clinical feature of mitochondrial trifunctional protein deficiency in adults."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Peripheral nerve involvement manifesting as sensory ataxia appeared later, during adolescence or adulthood.
    explanation: Characterizes peripheral neuropathy timing in adult MTP patients.
  - reference: PMID:35023662
    reference_title: "Mitochondrial trifunctional protein deficiency as a polyneuropathy etiology in childhood."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Electroneuromyography (ENMG) analysis showed moderate symmetric distal sensorimotor and axonal neuropathy.
    explanation: Confirms electrophysiological pattern of axonal neuropathy in MTP deficiency.
- name: Rhabdomyolysis
  frequency: FREQUENT
  description: 'Episodic rhabdomyolysis, typically triggered by fasting, febrile illness, or exercise, is a characteristic feature of MTP deficiency. Rhabdomyolysis and peripheral neuropathy tend to present later in childhood or in adulthood.

    '
  phenotype_term:
    preferred_term: Rhabdomyolysis
    term:
      id: HP:0003201
      label: Rhabdomyolysis
  evidence:
  - reference: PMID:32253025
    reference_title: "Sensory neuronopathy as a major clinical feature of mitochondrial trifunctional protein deficiency in adults."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Onset of the disease was characterized in all patients by rhabdomyolysis episodes occurring during childhood preceded by severe hypoglycemic episodes in three patients.
    explanation: Characterizes rhabdomyolysis episodes occurring during childhood as the initial disease presentation in this cohort.
- name: Retinopathy
  frequency: OCCASIONAL
  description: 'Pigmentary retinopathy is a complication of MTP deficiency, particularly associated with HADHA mutations. Retinopathy tends to present later in childhood and may progress to significant visual impairment.

    '
  phenotype_term:
    preferred_term: Pigmentary retinopathy
    term:
      id: HP:0000580
      label: Pigmentary retinopathy
  evidence:
  - reference: PMID:32253025
    reference_title: "Sensory neuronopathy as a major clinical feature of mitochondrial trifunctional protein deficiency in adults."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: MTPD should be screened for by performing plasma acylcarnitines in patients with chronic sensory neuronopathy and additional suggestive features such as exercise intolerance or retinopathy.
    explanation: Lists retinopathy among suggestive features of MTP deficiency.
- name: Hepatic involvement
  frequency: FREQUENT
  description: 'Hepatic involvement is common in severe and intermediate MTP deficiency and includes hepatopathy, liver dysfunction, and hepatic lipid accumulation during metabolic decompensation.

    '
  phenotype_term:
    preferred_term: Hepatic involvement
    term:
      id: HP:0001392
      label: Abnormality of the liver
  evidence:
  - reference: PMID:29502916
    reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Neonates and infants many present with sudden death, hepatopathy (Reye-like disease), hypoketotic hypoglycemia, rhabdomyolysis, myopathy, cardiomyopathy, and pulmonary edema."
    explanation: Review evidence directly lists hepatopathy in neonatal and infant TFP deficiency.
  - reference: PMID:31730477
    reference_title: "Evaluation of earlier versus later dietary management in long-chain 3-hydroxyacyl-CoA dehydrogenase or mitochondrial trifunctional protein deficiency: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Included studies suggested fewer heart and liver problems in screen-detected patients
    explanation: Clinical systematic-review evidence supports liver involvement as an MTP/LCHAD complication.
- name: Hypotonia
  frequency: FREQUENT
  description: 'Hypotonia is a common feature in infantile and early-onset MTP deficiency, and is part of the myopathic spectrum.

    '
  phenotype_term:
    preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia
  evidence:
  - reference: PMID:35023662
    reference_title: "Mitochondrial trifunctional protein deficiency as a polyneuropathy etiology in childhood."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Signs and symptoms of MTPD may present during infancy or later in life; those that begin after infancy include hypotonia, muscle pain, rhabdomyolysis, and peripheral neuropathy.
    explanation: Directly lists hypotonia as a presenting symptom of MTP deficiency.
- name: Myalgia
  frequency: FREQUENT
  description: 'Exercise-induced muscle pain and fatigue are characteristic features, particularly in milder and later-onset forms.

    '
  phenotype_term:
    preferred_term: Myalgia
    term:
      id: HP:0003326
      label: Myalgia
  evidence:
  - reference: PMID:28132977
    reference_title: "[Mitochondrial trifunctional protein deficiency: an adult patient with similar progress to Charcot-Marie-Tooth disease]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: He reported multiple episodes of exercise-induced severe muscle fatigue and brown urine in his childhood
    explanation: Supports exercise-induced myopathy in MTP deficiency.
- name: Respiratory failure
  frequency: OCCASIONAL
  description: 'Respiratory failure is a notable feature of severe and intermediate forms of MTP deficiency and contributes to mortality.

    '
  phenotype_term:
    preferred_term: Respiratory failure
    term:
      id: HP:0002878
      label: Respiratory failure
  evidence:
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: A notable feature of severe and intermediate form is respiratory failure.
    explanation: Directly identifies respiratory failure as a notable feature of MTP deficiency.
- name: Hypoparathyroidism
  frequency: OCCASIONAL
  description: 'Hypocalcemia due to hypoparathyroidism has been reported in MTP deficiency, particularly in Japanese patients. This feature is rarely reported in Caucasian patients and represents an atypical presentation.

    '
  phenotype_term:
    preferred_term: Hypoparathyroidism
    term:
      id: HP:0000829
      label: Hypoparathyroidism
  evidence:
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Our case is a complete TFP deficiency patient dominated presented with hypoparathyroidism, neutropenia and nephrotic syndrome
    explanation: Supports hypoparathyroidism as a reported atypical presentation.
- name: Distal muscle weakness
  frequency: FREQUENT
  description: 'Slowly progressive distal muscle weakness with areflexia and foot deformities is a characteristic feature, particularly of the mild myopathic form of MTP deficiency. It can mimic Charcot-Marie-Tooth disease.

    '
  phenotype_term:
    preferred_term: Distal muscle weakness
    term:
      id: HP:0002460
      label: Distal muscle weakness
  evidence:
  - reference: PMID:29956646
    reference_title: "HADHB mutations cause infantile-onset axonal Charcot-Marie-Tooth disease: A report of two cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Both had delayed motor development and slowly-progressing distal muscle weakness with areflexia and foot deformities.
    explanation: Directly describes distal muscle weakness as a presenting feature.
  - reference: PMID:28132977
    reference_title: "[Mitochondrial trifunctional protein deficiency: an adult patient with similar progress to Charcot-Marie-Tooth disease]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: A 45-year-old man presented to us due to slowly progressive muscle weakness and sensory disturbances in his lower limbs since his 40's.
    explanation: Confirms slowly progressive weakness in adult-onset MTP deficiency.
- name: Lactic acidosis
  frequency: OCCASIONAL
  description: 'Lactic acidosis can occur during metabolic decompensation episodes, reflecting impaired mitochondrial energy metabolism and secondary mitochondrial dysfunction.

    '
  phenotype_term:
    preferred_term: Lactic acidosis
    term:
      id: HP:0003128
      label: Lactic acidosis
  evidence:
  - reference: PMID:19880769
    reference_title: "Two novel HADHB gene mutations in a Korean patient with mitochondrial trifunctional protein deficiency."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Here, we report the case of a Korean male newborn who presented with severe lactic acidosis, seizures, and heart failure."
    explanation: Case evidence supports lactic acidosis as a severe neonatal MTPD presentation.
- name: Sudden death
  frequency: OCCASIONAL
  description: 'Sudden death may occur in severe neonatal forms of MTP deficiency during metabolic crises. The overall mortality is reported as high as 57.9% in a large retrospective analysis.

    '
  phenotype_term:
    preferred_term: Sudden death
    term:
      id: HP:0001699
      label: Sudden death
  evidence:
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The mortality of the present study is as high as 57.9%, which is linked with the onset age, phenotype, mutation type and muscular histology.
    explanation: Confirms high mortality rate in MTP deficiency from multiple causes including metabolic crises.
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The two patients with MTPD experienced metabolic crises and died following an infectious disease.
    explanation: Supports lethal metabolic crises in MTP deficiency.
biochemical:
- name: Long-chain 3-hydroxyacylcarnitines (C16-OH, C18:1-OH)
  presence: INCREASED
  context: 'Elevated long-chain 3-hydroxyacylcarnitines, particularly C16-OH and C18:1-OH, are the most common biochemical finding in MTP deficiency and serve as the primary diagnostic markers on newborn screening and acylcarnitine profiling.

    '
  readouts:
  - target: Impaired mitochondrial long-chain fatty acid beta-oxidation
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Elevated C16-OH and C18:1-OH report the blocked long-chain TFP-dependent beta-oxidation steps.
  evidence:
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Increased long-chain 3-OH-acylcarnitines (C16-OH, C18:1-OH) are the most common biochemical finding.
    explanation: Directly identifies elevated C16-OH and C18:1-OH acylcarnitines as the most common biochemical finding.
- name: Long-chain acylcarnitines
  presence: INCREASED
  context: 'Broadly elevated long-chain acylcarnitines are detectable by tandem mass spectrometry in blood samples from MTP-deficient patients. This includes multiple species reflecting impaired beta-oxidation of long-chain fatty acids.

    '
  readouts:
  - target: Impaired mitochondrial long-chain fatty acid beta-oxidation
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Elevated long-chain acylcarnitines report impaired long-chain fatty acid oxidation flux.
  evidence:
  - reference: PMID:32253025
    reference_title: "Sensory neuronopathy as a major clinical feature of mitochondrial trifunctional protein deficiency in adults."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: MTPD should be screened for by performing plasma acylcarnitines in patients with chronic sensory neuronopathy
    explanation: Supports acylcarnitine profiling as a diagnostic tool for MTP deficiency.
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Tandem mass spectrometry revealed that long‑chain acyl‑carnitine was markedly elevated in blood samples from the patients with MTPD."
    explanation: Patient data directly support elevation of long-chain acylcarnitines.
- name: Creatine kinase
  presence: INCREASED
  context: 'Creatine kinase (CK) and CK-MB are elevated during rhabdomyolysis episodes and may be chronically elevated in patients with myopathic involvement.

    '
  readouts:
  - target: Rhabdomyolysis
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: MONITORING
    interpretation: Increased CK reports muscle breakdown during rhabdomyolysis or myopathic crises.
  evidence:
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lactate dehydrogenase, creatine kinase (CK), CK‑MB and liver enzyme abnormalities were observed in routine examinations."
    explanation: Patient data support elevated CK and CK-MB in MTP deficiency.
- name: Hepatic lipid accumulation
  presence: PRESENT
  context: 'Fat accumulation in the liver and heart can be demonstrated on autopsy or biopsy, reflecting impaired fatty acid oxidation and lipid storage.

    '
  readouts:
  - target: Impaired mitochondrial long-chain fatty acid beta-oxidation
    relationship: READOUT_OF
    direction: PRESENT_ABSENT
    endpoint_context: DIAGNOSTIC
    interpretation: Tissue lipid accumulation reports failure to oxidize fatty acids in affected organs.
  evidence:
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The autopsy results for one child revealed fat accumulation in the liver and heart.
    explanation: Directly demonstrates hepatic and cardiac lipid accumulation on autopsy.
- name: Long-chain 3-hydroxy fatty acids
  presence: INCREASED
  context: 'Long-chain 3-hydroxy fatty acids accumulate when MTP/LCHAD-dependent beta-oxidation steps are blocked, and these intermediates can uncouple cardiac oxidative phosphorylation.

    '
  readouts:
  - target: Uncoupling of cardiac oxidative phosphorylation by long-chain 3-hydroxy fatty acids
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Accumulated long-chain 3-hydroxy fatty acids report the toxic intermediary pool implicated in oxidative-phosphorylation uncoupling.
  evidence:
  - reference: PMID:23065309
    reference_title: "Long-chain 3-hydroxy fatty acids accumulating in long-chain 3-hydroxyacyl-CoA dehydrogenase and mitochondrial trifunctional protein deficiencies uncouple oxidative phosphorylation in heart mitochondria."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "The present data indicate that major 3-hydroxylated fatty acids accumulating in MTP and LCHAD deficiencies behave as strong uncouplers of oxidative phosphorylation potentially impairing heart energy homeostasis."
    explanation: In vitro heart mitochondria data support accumulation and toxicity of long-chain 3-hydroxy fatty acids.
genetic:
- name: HADHA pathogenic variants causing MTP deficiency
  gene_term:
    preferred_term: HADHA
    term:
      id: hgnc:4801
      label: HADHA
  inheritance:
  - name: Autosomal recessive
    evidence:
    - reference: PMID:34878152
      reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: |-
        metabolic disease of fatty acid oxidation. MTPD is an autosomal recessive
        disorder caused by mutations in the HADHA gene, encoding the α‑subunit of a
        trifunctional protease, or in the HADHB gene, encoding the β‑subunit of a
        trifunctional protease.
      explanation: Family-report evidence directly states autosomal recessive inheritance and identifies HADHA as a causal gene.
  variants:
  - name: HADHA pathogenic variants
    description: 'HADHA encodes the alpha subunit of MTP, which harbors the LCHAD and enoyl-CoA hydratase catalytic domains. HADHA variants that disrupt protein folding or stability cause complete MTP deficiency affecting all three enzymatic activities. Note that the common c.1528G>C (p.E510Q) variant selectively affects LCHAD activity and causes isolated LCHAD deficiency rather than complete MTP deficiency. Fourteen mutations were identified in 26 alleles in Japanese patients.

      '
    gene:
      preferred_term: HADHA
      term:
        id: hgnc:4801
        label: HADHA
    evidence:
    - reference: PMID:28515471
      reference_title: "Clinical and molecular investigation of 14 Japanese patients with complete TFP deficiency: a comparison with Caucasian cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Fourteen mutations were identified in 26 alleles in Japanese patients, including two novel mutations
      explanation: Confirms the mutational spectrum in Japanese MTP patients.
  features: 'MTP deficiency can result from biallelic pathogenic variants in HADHA, which encodes the alpha subunit of mitochondrial trifunctional protein. HADHA variants alter MTP alpha-subunit conformation, stability, and enzyme-complex function; the common c.1528G>C variant is associated with isolated LCHAD deficiency rather than complete MTP deficiency.

    '
  evidence:
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: |-
      metabolic disease of fatty acid oxidation. MTPD is an autosomal recessive
      disorder caused by mutations in the HADHA gene, encoding the α‑subunit of a
      trifunctional protease, or in the HADHB gene, encoding the β‑subunit of a
      trifunctional protease.
    explanation: Directly supports HADHA mutations as one molecular cause of mitochondrial trifunctional protein deficiency.
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: COMPUTATIONAL
    snippet: |-
      Molecular mechanistic analysis indicated that the two variants affected the
      conformation of the α‑subunit of the MTP enzyme complex, and consequently
      affected the stability and function of the enzyme complex.
    explanation: Protein-structure modeling supports disruption of MTP complex stability and function by HADHA variants.
- name: HADHB pathogenic variants causing MTP deficiency
  gene_term:
    preferred_term: HADHB
    term:
      id: hgnc:4803
      label: HADHB
  association: Pathogenic Variants
  inheritance:
  - name: Autosomal recessive
    evidence:
    - reference: PMID:34878152
      reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: |-
        metabolic disease of fatty acid oxidation. MTPD is an autosomal recessive
        disorder caused by mutations in the HADHA gene, encoding the α‑subunit of a
        trifunctional protease, or in the HADHB gene, encoding the β‑subunit of a
        trifunctional protease.
      explanation: Family-report evidence directly states autosomal recessive inheritance and identifies HADHB as a causal gene.
  variants:
  - name: HADHB pathogenic variants
    description: 'HADHB encodes the beta subunit of MTP harboring the LCKAT catalytic domain. HADHB mutations are more frequent in Asian populations and typically cause complete TFP deficiency. No single common HADHB mutation has been identified. Compound heterozygous HADHB mutations can cause infantile-onset axonal Charcot-Marie-Tooth disease.

      '
    gene:
      preferred_term: HADHB
      term:
        id: hgnc:4803
        label: HADHB
    evidence:
    - reference: PMID:34543737
      reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Mutations in HADHB are more frequent in Asian descent with complete TFP deficiency and usually presented with atypical presentations.
      explanation: Confirms HADHB mutation frequency in Asian populations and atypical presentations.
    - reference: PMID:29956646
      reference_title: "HADHB mutations cause infantile-onset axonal Charcot-Marie-Tooth disease: A report of two cases."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Gene analysis identified two compound heterozygous mutations (c.184A>G/c.340A>G and c.488G>A/c.1175C>T, respectively) in the HADHB gene.
      explanation: Identifies specific HADHB compound heterozygous mutations causing axonal CMT.
  features: 'MTP deficiency can result from biallelic pathogenic variants in HADHB, which encodes the beta subunit of mitochondrial trifunctional protein. HADHB variants are relatively frequent in Asian patients with complete TFP deficiency and can produce atypical or neuromusculoskeletal presentations, including axonal Charcot-Marie-Tooth-like neuropathy.

    '
  evidence:
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: |-
      metabolic disease of fatty acid oxidation. MTPD is an autosomal recessive
      disorder caused by mutations in the HADHA gene, encoding the α‑subunit of a
      trifunctional protease, or in the HADHB gene, encoding the β‑subunit of a
      trifunctional protease.
    explanation: Directly supports HADHB mutations as one molecular cause of mitochondrial trifunctional protein deficiency.
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: |-
      presentations. The type of mutation, rather than residual enzyme activity seem
      to be more related to the phenotype and prognosis.
    explanation: Supports mutation type as a predictor of clinical phenotype.
  - reference: PMID:34543737
    reference_title: "Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: |-
      mutation type and muscular histology. Mutations in HADHB are more frequent in
      Asian descent with complete TFP deficiency and usually presented with atypical
      presentations.
    explanation: Supports the HADHB-associated molecular and clinical pattern in complete TFP deficiency.
  - reference: CGGV:assertion_65cb0124-8476-422c-924f-15fac7c95592-2018-05-08T160000.000Z
    reference_title: "HADHB / mitochondrial trifunctional protein deficiency (Definitive)"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "HADHB | HGNC:4803 | mitochondrial trifunctional protein deficiency | MONDO:0012172 | AR | Definitive"
    explanation: ClinGen classifies the HADHB-mitochondrial trifunctional protein deficiency gene-disease relationship as definitive with autosomal recessive inheritance.
treatments:
- name: Dietary fat modification with MCT supplementation
  description: 'The cornerstone of MTP deficiency management is restriction of long-chain dietary fat intake and supplementation with medium-chain triglycerides (MCT) which bypass the MTP-dependent step of beta-oxidation. Pre-symptomatic dietary management following newborn screening may be associated with a lower incidence of some complications.

    '
  treatment_term:
    preferred_term: dietary intervention
    term:
      id: MAXO:0000088
      label: dietary intervention
  target_mechanisms:
  - target: HADHA/HADHB molecular function deficiency in mitochondrial trifunctional protein
    treatment_effect: BYPASSES
    description: Medium-chain triglyceride supplementation supplies fatty acids that bypass the blocked long-chain MTP-dependent beta-oxidation steps.
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Diet should be modified to decrease long-chain fat intake along with supplementation of the diet with MCT oil and essential fatty acids."
      explanation: Review guidance supports reducing long-chain fat and supplementing MCT oil in TFP deficiency.
  - target: Impaired energy production during catabolic stress
    treatment_effect: MODULATES
    description: Lowering long-chain fat burden and using MCT oil reduces reliance on the impaired pathway during stress.
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Diet should be modified to decrease long-chain fat intake along with supplementation of the diet with MCT oil and essential fatty acids."
      explanation: Dietary modification is recommended to reduce metabolic stress from impaired long-chain FAO.
  evidence:
  - reference: PMID:31730477
    reference_title: "Evaluation of earlier versus later dietary management in long-chain 3-hydroxyacyl-CoA dehydrogenase or mitochondrial trifunctional protein deficiency: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: There is some evidence that dietary management following screen-detection might be associated with a lower incidence of some LCHAD and MTP deficiency-related complications.
    explanation: Supports dietary management as the primary treatment modality.
  - reference: PMID:31730477
    reference_title: "Evaluation of earlier versus later dietary management in long-chain 3-hydroxyacyl-CoA dehydrogenase or mitochondrial trifunctional protein deficiency: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Without dietary management the conditions are life-threatening.
    explanation: Emphasizes that dietary management is essential for survival.
- name: Triheptanoin therapy
  description: 'Triheptanoin is an odd-chain triglyceride nutritional therapy for long-chain fatty acid oxidation disorders. It provides anaplerotic substrate while bypassing the impaired long-chain fatty acid oxidation pathway and is supported by LC-FAOD trial and cohort evidence.

    '
  treatment_term:
    preferred_term: nutritional supplementation
    term:
      id: MAXO:0000106
      label: nutritional supplementation
    therapeutic_agent:
    - preferred_term: triheptanoin
  target_phenotypes:
  - preferred_term: Cardiomyopathy
    term:
      id: HP:0001638
      label: Cardiomyopathy
  - preferred_term: Rhabdomyolysis
    term:
      id: HP:0003201
      label: Rhabdomyolysis
  - preferred_term: Myalgia
    term:
      id: HP:0003326
      label: Myalgia
  target_mechanisms:
  - target: Impaired mitochondrial long-chain fatty acid beta-oxidation
    treatment_effect: BYPASSES
    description: Triheptanoin supplies medium odd-chain fatty acid calories that can support energy metabolism without relying on the blocked long-chain TFP-dependent beta-oxidation steps.
    evidence:
    - reference: PMID:32840329
      reference_title: "Long-chain fatty acid oxidation disorders and current management strategies."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "In recent years, the use of medium, odd-chain fatty acids, such as triheptanoin, have been studied as a treatment of LC-FAODs due to its anaplerotic properties."
      explanation: Review evidence supports triheptanoin as an anaplerotic treatment strategy for long-chain fatty acid oxidation disorders.
  - target: Impaired energy production during catabolic stress
    treatment_effect: MODULATES
    description: Triheptanoin is intended to reduce catabolic decompensation episodes and support energy production in LC-FAOD.
    evidence:
    - reference: DOI:10.1186/s13052-024-01782-y
      reference_title: "Triheptanoin in patients with long-chain fatty acid oxidation disorders: clinical experience in Italy"
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Triheptanoin was well tolerated and decreased the number of intercurrent catabolic episodes, metabolic decompensation episodes requiring hospitalisation, and the annualised rate and duration of hospitalisations."
      explanation: Retrospective human cohort data support fewer catabolic and metabolic decompensation episodes during triheptanoin treatment.
  evidence:
  - reference: PMID:32840329
    reference_title: "Long-chain fatty acid oxidation disorders and current management strategies."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Due to favorable safety and efficacy data from clinical trials, this novel agent has the potential to transform the treatment of LC-FAODs and improve patient outcomes in this patient population."
    explanation: Clinical review evidence supports triheptanoin as a therapeutic option with favorable trial data in LC-FAOD.
  - reference: clinicaltrials:NCT01379625
    reference_title: "Phase 2 Study of Triheptanoin for Treatment of Long-Chain Fatty Acid Oxidation Disorders"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: This study will determine if a new experimental oil called Triheptanoin can decrease the muscle pain and increase the heart function and the amount of energy in patients with long-chain fatty acid oxidation disorders.
    explanation: Phase 2 trial record supports triheptanoin evaluation for muscle pain, cardiac function, and energy outcomes in LC-FAOD.
  - reference: clinicaltrials:NCT01886378
    reference_title: "An Open-label Phase 2 Study to Assess Safety and Clinical Effects of UX007 in Subjects With Long-Chain Fatty Acid Oxidation Disorders (LC-FAOD)"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The primary objective of the study was to evaluate the impact of UX007 on acute clinical pathophysiology associated with LC-FAOD following 24 weeks of treatment.
    explanation: Phase 2 trial record supports UX007/triheptanoin evaluation against acute LC-FAOD clinical pathophysiology.
  - reference: clinicaltrials:NCT05933200
    reference_title: "A Randomized, Double-blind, Multicenter Study to Determine the Effect of Triheptanoin Compared With Even-chain, Medium-chain Triglycerides (MCT) on Major Clinical Events (MCEs) in Pediatric Patients With Long-chain Fatty Acid Oxidation Disorders (LC-FAOD)"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The main goal of this study is to evaluate the effects of triheptanoin versus Medium-chain Triglycerides (MCT) on frequency of Major Clinical Events (MCEs).
    explanation: Phase 3 trial record supports ongoing randomized evaluation of triheptanoin versus MCT for major clinical events.
  - reference: clinicaltrials:NCT02214160
    reference_title: "An Open-label Long-Term Safety and Efficacy Extension Study in Subjects With Long-Chain Fatty Acid Oxidation Disorders (LC-FAOD) Previously Enrolled in UX007 or Triheptanoin Studies"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The primary objective of this study is to evaluate the long-term safety and efficacy of UX007 in participants with LC-FAOD.
    explanation: Extension-study record supports long-term safety and efficacy evaluation for UX007/triheptanoin in LC-FAOD.
- name: Avoidance of fasting and catabolic stress
  description: 'Preventing prolonged fasting is critical. Frequent meals, cornstarch supplementation at night, and emergency protocols with IV glucose during illness help prevent metabolic decompensation.

    '
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  target_mechanisms:
  - target: Impaired energy production during catabolic stress
    treatment_effect: MODULATES
    description: Avoiding fasting and illness-triggered catabolism reduces episodes when impaired FAO cannot meet energy demand.
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Therapy is similar to VLCAD deficiency and includes avoiding the physiologic triggers of fasting and illness."
      explanation: Review guidance supports avoiding fasting and illness triggers to reduce catabolic energy stress.
  evidence:
  - reference: PMID:35023662
    reference_title: "Mitochondrial trifunctional protein deficiency as a polyneuropathy etiology in childhood."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: acute relapsing episodes triggered by fasting or illnesses
    explanation: Confirms fasting and illness as triggers for metabolic crises, supporting avoidance strategy.
- name: Carnitine supplementation
  description: 'Low-dose L-carnitine is a controversial supportive option in MTP deficiency, and high-dose intravenous carnitine during decompensation is not recommended.

    '
  treatment_term:
    preferred_term: carnitine supplementation
    term:
      id: MAXO:0010006
      label: carnitine supplementation
    therapeutic_agent:
    - preferred_term: carnitine
      term:
        id: CHEBI:17126
        label: carnitine
  target_mechanisms:
  - target: Impaired mitochondrial long-chain fatty acid beta-oxidation
    treatment_effect: MODULATES
    description: Low-dose carnitine is a conditional supportive intervention rather than correction of the TFP enzyme block.
    evidence:
    - reference: PMID:29502916
      reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Carnitine supplementation remains controversial, but low doses do not cause harm."
      explanation: Review guidance supports only a cautious, low-dose role for carnitine in TFP deficiency.
  evidence:
  - reference: PMID:29502916
    reference_title: "Inborn Errors of Metabolism with Myopathy: Defects of Fatty Acid Oxidation and the Carnitine Shuttle System."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Carnitine supplementation remains controversial, but low doses do not cause harm. Intravenous supplementation of carnitine in high doses during decompensation is not recommended."
    explanation: Supports a cautious carnitine entry while preventing overstatement of routine high-dose use.
- name: Bezafibrate therapy
  description: 'Bezafibrate, a PPAR-alpha agonist, has been shown to upregulate MTP expression in control fibroblasts and improve fatty acid oxidation capacities in a subset (23%) of MTP-deficient patient cell lines, particularly those heterozygous for the common c.1528G>C mutation.

    '
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    therapeutic_agent:
    - preferred_term: bezafibrate
      term:
        id: CHEBI:47612
        label: bezafibrate
  target_mechanisms:
  - target: HADHA/HADHB molecular function deficiency in mitochondrial trifunctional protein
    treatment_effect: MODULATES
    description: Bezafibrate can upregulate HADHA/HADHB expression and residual MTP activity in responsive fibroblast genotypes.
    evidence:
    - reference: PMID:26109258
      reference_title: "Mitochondrial trifunctional protein deficiency in human cultured fibroblasts: effects of bezafibrate."
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "activities of LCHAD and LCKAT, and stimulated FAO capacities, clearly indicating that MTP is pharmacologically up-regulated by bezafibrate in human fibroblasts."
      explanation: Human fibroblast evidence supports bezafibrate as a pharmacologic modulator of residual MTP function.
  evidence:
  - reference: PMID:26109258
    reference_title: "Mitochondrial trifunctional protein deficiency in human cultured fibroblasts: effects of bezafibrate."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: MTP is pharmacologically up-regulated by bezafibrate in human fibroblasts.
    explanation: Confirms pharmacological upregulation of MTP by bezafibrate.
  notes: 'Bezafibrate is an investigational therapy for MTP deficiency. Response is genotype-dependent, with only a subset of patients expected to benefit.

    '
- name: Newborn screening
  description: 'MTP deficiency can be detected by newborn screening using tandem mass spectrometry to identify elevated long-chain 3-hydroxyacylcarnitines. Screen detection may be associated with fewer cardiac and hepatic complications, though mitigated phenotypes can be missed by screening.

    '
  treatment_term:
    preferred_term: disease screening
    term:
      id: MAXO:0000124
      label: disease screening
  target_phenotypes:
  - preferred_term: Cardiomyopathy
    term:
      id: HP:0001638
      label: Cardiomyopathy
  - preferred_term: Hepatic involvement
    term:
      id: HP:0001392
      label: Abnormality of the liver
  evidence:
  - reference: PMID:31730477
    reference_title: "Evaluation of earlier versus later dietary management in long-chain 3-hydroxyacyl-CoA dehydrogenase or mitochondrial trifunctional protein deficiency: a systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Included studies suggested fewer heart and liver problems in screen-detected patients, but inconsistent results for mortality.
    explanation: Supports newborn screening benefit for reducing cardiac and hepatic complications.
  - reference: PMID:30682426
    reference_title: "HADHA and HADHB gene associated phenotypes - Identification of rare variants in a patient cohort by Next Generation Sequencing."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The mitigated phenotypes of this treatable disease were missed by the newborn screening, highlighting the importance of phenotype-based NGS analysis
    explanation: Notes that milder MTP phenotypes may be missed by standard newborn screening.
- name: Genetic counseling
  description: 'Genetic counseling for affected families including discussion of autosomal recessive inheritance, 25% recurrence risk, carrier testing, and prenatal diagnosis options. Maternal complications including HELLP syndrome and acute fatty liver of pregnancy may occur in pregnancies carrying affected fetuses.

    '
  treatment_term:
    preferred_term: genetic counseling
    term:
      id: MAXO:0000079
      label: genetic counseling
  target_mechanisms:
  - target: HADHA/HADHB molecular function deficiency in mitochondrial trifunctional protein
    treatment_effect: MODULATES
    description: Counseling addresses the autosomal recessive HADHA/HADHB molecular cause, recurrence risk, carrier testing, and prenatal diagnosis rather than directly changing metabolism.
    evidence:
    - reference: PMID:34878152
      reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: |-
        metabolic disease of fatty acid oxidation. MTPD is an autosomal recessive
        disorder caused by mutations in the HADHA gene, encoding the α‑subunit of a
        trifunctional protease, or in the HADHB gene, encoding the β‑subunit of a
        trifunctional protease.
      explanation: Human family evidence supports genetics-informed counseling around the biallelic HADHA/HADHB cause.
  evidence:
  - reference: PMID:28515471
    reference_title: "Clinical and molecular investigation of 14 Japanese patients with complete TFP deficiency: a comparison with Caucasian cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Maternal hemolysis, elevated liver enzymes and low platelet count syndrome and acute fatty liver of pregnancy were noted in two and one mothers, respectively.
    explanation: Maternal complications necessitate genetic counseling and pregnancy monitoring.
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Using amniotic fluid prenatal diagnostic testing, the unborn child was confirmed to carry only c.2107G>A (p.G703R).
    explanation: Demonstrates availability and utility of prenatal diagnosis for MTP deficiency.
- name: Acute crisis management
  description: 'Emergency management of metabolic decompensation episodes includes intravenous glucose to suppress catabolism, correction of metabolic acidosis, monitoring for cardiac arrhythmias, and management of rhabdomyolysis with aggressive hydration.

    '
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  target_mechanisms:
  - target: Impaired energy production during catabolic stress
    treatment_effect: MODULATES
    description: Acute glucose support suppresses catabolism and provides carbohydrate fuel when long-chain FAO cannot meet energy demand.
    evidence:
    - reference: PMID:39203843
      reference_title: "Nutritional Management of Patients with Fatty Acid Oxidation Disorders."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "The main measure in emergency hospital treatment is the administration of IV glucose."
      explanation: FAOD nutritional guidance supports IV glucose as the emergency measure to suppress catabolism.
  evidence:
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The two patients with MTPD experienced metabolic crises and died following an infectious disease.
    explanation: Metabolic crises during infectious illness underscore need for aggressive crisis management.
- name: Physical therapy and rehabilitation
  description: 'Physical therapy for patients with peripheral neuropathy and myopathy to maintain mobility, prevent contractures, and manage distal muscle weakness and foot deformities.

    '
  treatment_term:
    preferred_term: physical therapy
    term:
      id: MAXO:0000011
      label: physical therapy
  target_phenotypes:
  - preferred_term: Peripheral neuropathy
    term:
      id: HP:0009830
      label: Peripheral neuropathy
  - preferred_term: Distal muscle weakness
    term:
      id: HP:0002460
      label: Distal muscle weakness
  evidence:
  - reference: PMID:29956646
    reference_title: "HADHB mutations cause infantile-onset axonal Charcot-Marie-Tooth disease: A report of two cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Both had delayed motor development and slowly-progressing distal muscle weakness with areflexia and foot deformities.
    explanation: Distal weakness and foot deformities support need for physical therapy and rehabilitation.
  - reference: PMID:29956646
    reference_title: "HADHB mutations cause infantile-onset axonal Charcot-Marie-Tooth disease: A report of two cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The electrophysiology findings were compatible with axonal polyneuropathy in both patients.
    explanation: Axonal polyneuropathy supports rehabilitation-focused management of neuropathic functional impairment.
environmental:
- name: Fasting
  description: 'Prolonged fasting is a major trigger for metabolic decompensation in MTP deficiency, as the body cannot effectively oxidize long-chain fatty acids for energy during periods of caloric deprivation.

    '
  evidence:
  - reference: PMID:35023662
    reference_title: "Mitochondrial trifunctional protein deficiency as a polyneuropathy etiology in childhood."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: acute relapsing episodes triggered by fasting or illnesses
    explanation: Confirms fasting as a trigger for acute episodes.
- name: Intercurrent illness
  description: 'Febrile illness and infections increase metabolic demands and promote catabolism, triggering decompensation episodes including rhabdomyolysis and hypoglycemia.

    '
  evidence:
  - reference: PMID:34878152
    reference_title: "Analysis of a family with mitochondrial trifunctional protein deficiency caused by HADHA gene mutations."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The two patients with MTPD experienced metabolic crises and died following an infectious disease.
    explanation: Directly demonstrates infectious disease as a fatal trigger.
- name: Prolonged exercise
  description: 'Intense or prolonged physical exercise can precipitate rhabdomyolysis and muscle breakdown in MTP deficiency due to reliance on fatty acid oxidation for sustained muscle energy.

    '
  evidence:
  - reference: PMID:28132977
    reference_title: "[Mitochondrial trifunctional protein deficiency: an adult patient with similar progress to Charcot-Marie-Tooth disease]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: He reported multiple episodes of exercise-induced severe muscle fatigue and brown urine in his childhood
    explanation: Confirms exercise as a trigger for myoglobinuria episodes.
notes: 'MTP deficiency should be distinguished from isolated LCHAD deficiency (caused specifically by the HADHA c.1528G>C mutation affecting only LCHAD activity), which is more common. Complete TFP deficiency involves loss of all three enzymatic activities and tends to have a more severe prognosis. HADHB mutations can present as isolated axonal Charcot-Marie-Tooth disease, and MTP deficiency should be considered in the differential diagnosis of hereditary sensorimotor neuropathies. The genotype-phenotype correlation shows that HADHA mutations tend to produce a phenotype more similar to LCHAD deficiency, while HADHB mutations produce a neuromusculoskeletal phenotype.

  '
references:
- reference: PMID:36063482
  title: Long-Chain Hydroxyacyl-CoA Dehydrogenase Deficiency / Trifunctional Protein Deficiency
  tags:
  - GeneReviews
  findings: []
- reference: DOI:10.1002/jimd.12372
  title: The spectrum of peripheral neuropathy in disorders of the mitochondrial trifunctional protein
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: The spectrum of peripheral neuropathy in disorders of the mitochondrial trifunctional protein
    supporting_text: Peripheral neuropathy is a known irreversible long‐term complication of long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD) and mitochondrial trifunctional protein deficiency (MTPD), two inherited disorders of mitochondrial long‐chain fatty acid oxidation.
    evidence:
    - reference: DOI:10.1002/jimd.12372
      reference_title: The spectrum of peripheral neuropathy in disorders of the mitochondrial trifunctional protein
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Peripheral neuropathy is a known irreversible long‐term complication of long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD) and mitochondrial trifunctional protein deficiency (MTPD), two inherited disorders of mitochondrial long‐chain fatty acid oxidation.
      explanation: Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.
- reference: DOI:10.1002/jimd.12502
  title: Genetic, biochemical, and clinical spectrum of patients with mitochondrial trifunctional protein deficiency identified after the introduction of newborn screening in the Netherlands
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: Long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD) is included in many newborn screening (NBS) programs.
    supporting_text: Long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD) is included in many newborn screening (NBS) programs.
    evidence:
    - reference: DOI:10.1002/jimd.12502
      reference_title: Genetic, biochemical, and clinical spectrum of patients with mitochondrial trifunctional protein deficiency identified after the introduction of newborn screening in the Netherlands
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD) is included in many newborn screening (NBS) programs.
      explanation: Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.
- reference: DOI:10.1007/s40267-021-00816-3
  title: 'Triheptanoin in the management of long-chain fatty acid oxidation disorders: a profile of its use'
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: 'Triheptanoin in the management of long-chain fatty acid oxidation disorders: a profile of its use'
    supporting_text: 'Triheptanoin in the management of long-chain fatty acid oxidation disorders: a profile of its use'
- reference: DOI:10.1016/j.ymgme.2012.02.015
  title: Observations regarding retinopathy in mitochondrial trifunctional protein deficiencies
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: Observations regarding retinopathy in mitochondrial trifunctional protein deficiencies
    supporting_text: Observations regarding retinopathy in mitochondrial trifunctional protein deficiencies
- reference: DOI:10.1038/s42003-023-05268-1
  title: A G1528C Hadha knock-in mouse model recapitulates aspects of human clinical phenotypes for long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) is a fatty acid oxidation disorder (FAOD) caused by a pathogenic variant, c.1528 G > C, in HADHA encoding the alpha subunit of trifunctional protein (TFPα).
    supporting_text: Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) is a fatty acid oxidation disorder (FAOD) caused by a pathogenic variant, c.1528 G > C, in HADHA encoding the alpha subunit of trifunctional protein (TFPα).
    evidence:
    - reference: DOI:10.1038/s42003-023-05268-1
      reference_title: A G1528C Hadha knock-in mouse model recapitulates aspects of human clinical phenotypes for long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) is a fatty acid oxidation disorder (FAOD) caused by a pathogenic variant, c.1528 G > C, in HADHA encoding the alpha subunit of trifunctional protein (TFPα).
      explanation: Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.
- reference: DOI:10.1167/iovs.65.11.22
  title: iPSC-Derived LCHADD Retinal Pigment Epithelial Cells Are Susceptible to Lipid Peroxidation and Rescued by Transfection of a Wildtype AAV-<i>HADHA</i> Vector
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: iPSC-Derived LCHADD Retinal Pigment Epithelial Cells Are Susceptible to Lipid Peroxidation and Rescued by Transfection of a Wildtype AAV-<i>HADHA</i> Vector
    supporting_text: iPSC-Derived LCHADD Retinal Pigment Epithelial Cells Are Susceptible to Lipid Peroxidation and Rescued by Transfection of a Wildtype AAV-<i>HADHA</i> Vector
- reference: DOI:10.1172/jci.insight.176887
  title: Mitochondrial bioenergetics and cardiolipin remodeling abnormalities in mitochondrial trifunctional protein deficiency
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: Mitochondrial bioenergetics and cardiolipin remodeling abnormalities in mitochondrial trifunctional protein deficiency
    supporting_text: Mitochondrial bioenergetics and cardiolipin remodeling abnormalities in mitochondrial trifunctional protein deficiency
- reference: DOI:10.1186/s13023-018-0875-6
  title: Fatal pitfalls in newborn screening for mitochondrial trifunctional protein (MTP)/long-chain 3-Hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: Fatal pitfalls in newborn screening for mitochondrial trifunctional protein (MTP)/long-chain 3-Hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency
    supporting_text: Fatal pitfalls in newborn screening for mitochondrial trifunctional protein (MTP)/long-chain 3-Hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency
- reference: DOI:10.1186/s13052-024-01782-y
  title: 'Triheptanoin in patients with long-chain fatty acid oxidation disorders: clinical experience in Italy'
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: Long-chain fatty acid oxidation disorders (LC-FAOD) are rare and potentially life-threatening diseases that cause deficient energy production and accumulation of toxic metabolites.
    supporting_text: Long-chain fatty acid oxidation disorders (LC-FAOD) are rare and potentially life-threatening diseases that cause deficient energy production and accumulation of toxic metabolites.
    evidence:
    - reference: DOI:10.1186/s13052-024-01782-y
      reference_title: 'Triheptanoin in patients with long-chain fatty acid oxidation disorders: clinical experience in Italy'
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Long-chain fatty acid oxidation disorders (LC-FAOD) are rare and potentially life-threatening diseases that cause deficient energy production and accumulation of toxic metabolites.
      explanation: Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.
- reference: DOI:10.3389/fped.2021.606194
  title: Newborn Screening for Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase and Mitochondrial Trifunctional Protein Deficiencies Using Acylcarnitines Measurement in Dried Blood Spots—A Systematic Review of Test Accuracy
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare autosomal recessive fatty acid β-oxidation disorders.
    supporting_text: Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare autosomal recessive fatty acid β-oxidation disorders.
    evidence:
    - reference: DOI:10.3389/fped.2021.606194
      reference_title: Newborn Screening for Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase and Mitochondrial Trifunctional Protein Deficiencies Using Acylcarnitines Measurement in Dried Blood Spots—A Systematic Review of Test Accuracy
      supports: SUPPORT
      evidence_source: OTHER
      snippet: Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare autosomal recessive fatty acid β-oxidation disorders.
      explanation: Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.
- reference: DOI:10.3390/ijms262010140
  title: 'How Genes Meet Diet in LCHAD Deficiency: Nutrigenomics of Fatty Acid Oxidation Disorder'
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: Mitochondrial long-chain fatty acid β-oxidation supplies energy to the heart, liver, and skeletal muscle.
    supporting_text: Mitochondrial long-chain fatty acid β-oxidation supplies energy to the heart, liver, and skeletal muscle.
    evidence:
    - reference: DOI:10.3390/ijms262010140
      reference_title: 'How Genes Meet Diet in LCHAD Deficiency: Nutrigenomics of Fatty Acid Oxidation Disorder'
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Mitochondrial long-chain fatty acid β-oxidation supplies energy to the heart, liver, and skeletal muscle.
      explanation: Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.
- reference: DOI:10.3390/ijns9030048
  title: New Acylcarnitine Ratio as a Reliable Indicator of Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase Deficiency
  found_in:
  - Mitochondrial_Trifunctional_Protein_Deficiency-deep-research-falcon.md
  findings:
  - statement: Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare fatal disorders of fatty acid β-oxidation with no apparent genotype–phenotype correlation.
    supporting_text: Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare fatal disorders of fatty acid β-oxidation with no apparent genotype–phenotype correlation.
    evidence:
    - reference: DOI:10.3390/ijns9030048
      reference_title: New Acylcarnitine Ratio as a Reliable Indicator of Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase Deficiency
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare fatal disorders of fatty acid β-oxidation with no apparent genotype–phenotype correlation.
      explanation: Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.

📚

References & Deep Research

References

PMID:36063482

Long-Chain Hydroxyacyl-CoA Dehydrogenase Deficiency / Trifunctional Protein Deficiency

No top-level findings curated for this source.

DOI:10.1002/jimd.12372

The spectrum of peripheral neuropathy in disorders of the mitochondrial trifunctional protein

1 finding

The spectrum of peripheral neuropathy in disorders of the mitochondrial trifunctional protein

"Peripheral neuropathy is a known irreversible long‐term complication of long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD) and mitochondrial trifunctional protein deficiency (MTPD), two inherited disorders of mitochondrial long‐chain fatty acid oxidation."

Show evidence (1 reference)

DOI:10.1002/jimd.12372 SUPPORT Human Clinical

Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.

DOI:10.1002/jimd.12502

Genetic, biochemical, and clinical spectrum of patients with mitochondrial trifunctional protein deficiency identified after the introduction of newborn screening in the Netherlands

1 finding

Long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD) is included in many newborn screening (NBS) programs.

"Long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD) is included in many newborn screening (NBS) programs."

Show evidence (1 reference)

DOI:10.1002/jimd.12502 SUPPORT Human Clinical

"Long‐chain 3‐hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD) is included in many newborn screening (NBS) programs."

Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.

DOI:10.1007/s40267-021-00816-3

Triheptanoin in the management of long-chain fatty acid oxidation disorders: a profile of its use

1 finding

Triheptanoin in the management of long-chain fatty acid oxidation disorders: a profile of its use

"Triheptanoin in the management of long-chain fatty acid oxidation disorders: a profile of its use"

DOI:10.1016/j.ymgme.2012.02.015

Observations regarding retinopathy in mitochondrial trifunctional protein deficiencies

1 finding

Observations regarding retinopathy in mitochondrial trifunctional protein deficiencies

"Observations regarding retinopathy in mitochondrial trifunctional protein deficiencies"

DOI:10.1038/s42003-023-05268-1

A G1528C Hadha knock-in mouse model recapitulates aspects of human clinical phenotypes for long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency

1 finding

Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) is a fatty acid oxidation disorder (FAOD) caused by a pathogenic variant, c.1528 G > C, in HADHA encoding the alpha subunit of trifunctional protein (TFPα).

"Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) is a fatty acid oxidation disorder (FAOD) caused by a pathogenic variant, c.1528 G > C, in HADHA encoding the alpha subunit of trifunctional protein (TFPα)."

Show evidence (1 reference)

DOI:10.1038/s42003-023-05268-1 SUPPORT Model Organism

Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.

DOI:10.1167/iovs.65.11.22

iPSC-Derived LCHADD Retinal Pigment Epithelial Cells Are Susceptible to Lipid Peroxidation and Rescued by Transfection of a Wildtype AAV-HADHA Vector

1 finding

iPSC-Derived LCHADD Retinal Pigment Epithelial Cells Are Susceptible to Lipid Peroxidation and Rescued by Transfection of a Wildtype AAV-HADHA Vector

"iPSC-Derived LCHADD Retinal Pigment Epithelial Cells Are Susceptible to Lipid Peroxidation and Rescued by Transfection of a Wildtype AAV-HADHA Vector"

DOI:10.1172/jci.insight.176887

Mitochondrial bioenergetics and cardiolipin remodeling abnormalities in mitochondrial trifunctional protein deficiency

1 finding

Mitochondrial bioenergetics and cardiolipin remodeling abnormalities in mitochondrial trifunctional protein deficiency

"Mitochondrial bioenergetics and cardiolipin remodeling abnormalities in mitochondrial trifunctional protein deficiency"

DOI:10.1186/s13023-018-0875-6

Fatal pitfalls in newborn screening for mitochondrial trifunctional protein (MTP)/long-chain 3-Hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency

1 finding

Fatal pitfalls in newborn screening for mitochondrial trifunctional protein (MTP)/long-chain 3-Hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency

"Fatal pitfalls in newborn screening for mitochondrial trifunctional protein (MTP)/long-chain 3-Hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency"

DOI:10.1186/s13052-024-01782-y

Triheptanoin in patients with long-chain fatty acid oxidation disorders: clinical experience in Italy

1 finding

Long-chain fatty acid oxidation disorders (LC-FAOD) are rare and potentially life-threatening diseases that cause deficient energy production and accumulation of toxic metabolites.

"Long-chain fatty acid oxidation disorders (LC-FAOD) are rare and potentially life-threatening diseases that cause deficient energy production and accumulation of toxic metabolites."

Show evidence (1 reference)

DOI:10.1186/s13052-024-01782-y SUPPORT Human Clinical

"Long-chain fatty acid oxidation disorders (LC-FAOD) are rare and potentially life-threatening diseases that cause deficient energy production and accumulation of toxic metabolites."

Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.

DOI:10.3389/fped.2021.606194

Newborn Screening for Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase and Mitochondrial Trifunctional Protein Deficiencies Using Acylcarnitines Measurement in Dried Blood Spots—A Systematic Review of Test Accuracy

1 finding

Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare autosomal recessive fatty acid β-oxidation disorders.

"Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare autosomal recessive fatty acid β-oxidation disorders."

Show evidence (1 reference)

DOI:10.3389/fped.2021.606194 SUPPORT Other

"Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare autosomal recessive fatty acid β-oxidation disorders."

Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.

DOI:10.3390/ijms262010140

How Genes Meet Diet in LCHAD Deficiency: Nutrigenomics of Fatty Acid Oxidation Disorder

1 finding

Mitochondrial long-chain fatty acid β-oxidation supplies energy to the heart, liver, and skeletal muscle.

"Mitochondrial long-chain fatty acid β-oxidation supplies energy to the heart, liver, and skeletal muscle."

Show evidence (1 reference)

DOI:10.3390/ijms262010140 SUPPORT Human Clinical

"Mitochondrial long-chain fatty acid β-oxidation supplies energy to the heart, liver, and skeletal muscle."

Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.

DOI:10.3390/ijns9030048

New Acylcarnitine Ratio as a Reliable Indicator of Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase Deficiency

1 finding

Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare fatal disorders of fatty acid β-oxidation with no apparent genotype–phenotype correlation.

"Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (MTP) deficiencies are rare fatal disorders of fatty acid β-oxidation with no apparent genotype–phenotype correlation."

Show evidence (1 reference)

DOI:10.3390/ijns9030048 SUPPORT Human Clinical

Deep research cited this publication as relevant literature for Mitochondrial Trifunctional Protein Deficiency.

Deep Research

Falcon ▸

Disease Characteristics Research Template

Edison Scientific Literature 30 citations 2026-05-10T05:15:51.156873

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

Disease Name: Mitochondrial Trifunctional Protein Deficiency
MONDO ID: (if available)
Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Mitochondrial Trifunctional Protein Deficiency covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

What is the disease? Provide a concise overview.
What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
What are the common synonyms and alternative names?
Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
Risk Factors:

Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases
Genetic risk factors (causal variants, susceptibility loci, modifier genes)
Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
Protective Factors:

Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases
Genetic protective factors (protective variants, modifier alleles)
Environmental protective factors (diet, lifestyle, exposures that reduce risk)
Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene
Pathogenic Variants:
Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
Variant type/class (missense, frameshift, nonsense, splice-site, structural)
Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
Functional consequences (loss of function, gain of function, dominant negative)
Modifier Genes: Genes that modify disease severity or expression
Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases
Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

Search first: CDC databases, WHO, PubMed, NHANES
Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc
Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

Search first: Gene Ontology (GO), Reactome, KEGG, PubMed
Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold
Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA
Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

Search first: ImmPort, Immunome Database, IEDB, Gene Ontology
Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

Search first: PubMed, Gene Ontology, Reactome
Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

Search first: BRENDA, UniProt, KEGG, OMIM, PubMed
Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Molecular Profiling (if available):
Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
Advanced Technologies (if applicable):
Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

Organ Level:
Primary organs directly affected
Secondary organ involvement (complications, secondary effects)
Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT
Tissue and Cell Level:
Specific tissue types affected (epithelial, connective, muscle, nervous)
Specific cell populations targeted (with Cell Ontology terms)

Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB
Subcellular Level:
Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas
Localization:
Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

Onset:
Typical age of onset (congenital, pediatric, adult, geriatric)
Onset pattern (acute, subacute, chronic, insidious)

Search first: OMIM, Orphanet, HPO, PubMed
Progression:
Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
Progression rate (rapid, slow, variable)
Disease course pattern (episodic, relapsing-remitting, progressive, stable)
Disease duration (self-limited, chronic lifelong)

Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM
Patterns:
Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

Epidemiology:
Prevalence (cases per 100,000 at given time)
Incidence (new cases per 100,000 per year)

Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries
For Genetic Etiology:
Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
Population Demographics:
Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
Geographic distribution of specific variants
Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

Clinical Tests:
Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
Genetic Testing:

Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen
Overview of recommended genetic testing approach
Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
FISH > Search first: ClinVar, cytogenetics databases, PubMed
Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
Omics-Based Diagnostics (if applicable):
RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
Clinical Criteria:
Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
Screening:
Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

Survival and Mortality:
Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
Morbidity and Function:
Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
Disease Course:
Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
Prediction:
Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

Pharmacotherapy:
Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
Advanced Therapeutics:
Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
Surgical and Interventional:
Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
Supportive and Rehabilitative:
Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
Experimental:
Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
Treatment Outcomes:
Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
Treatment Strategy:
Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

Prevention Levels:
Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
Immunization: Vaccine strategies (if applicable)

Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database
Screening and Early Detection:
Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
Behavioral Interventions: Lifestyle modifications to reduce risk

Search first: CDC, WHO, behavioral intervention databases, Cochrane Library
Counseling: Genetic counseling (risk assessment, family planning guidance)

Search first: NSGC resources, ACMG guidelines, GeneReviews
Public Health:
Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
Prophylaxis: Preventive medications or procedures

Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

Taxonomy: Species affected (with NCBI Taxon identifiers)

Search first: NCBI Taxonomy
Breed: Specific breeds affected (with VBO identifiers if applicable)

Search first: VBO (Vertebrate Breed Ontology)
Gene: Orthologous genes in other species (with NCBI Gene IDs)

Search first: NCBI Gene
Natural Disease:
Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
Comparative Biology:
Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
Transmission (if applicable):
Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

Model Types:
Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
Genetic Models:
Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
Model Characteristics:
Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
Applications:
Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
Resources:
Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

Cite primary literature (PMID preferred) for all mechanistic and clinical claims
Prioritize recent reviews and landmark papers
Include direct quotes from abstracts where possible to support key statements
Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Comprehensive Research Report: Mitochondrial Trifunctional Protein Deficiency (MTPD)

Executive summary

Mitochondrial trifunctional protein deficiency (MTPD) is an autosomal recessive long‑chain fatty‑acid β‑oxidation disorder caused by biallelic pathogenic variants in HADHA and/or HADHB, encoding the α and β subunits of the mitochondrial trifunctional protein (TFP/MTP). It presents as a spectrum ranging from lethal neonatal cardiomyopathy/metabolic crisis to later‑onset episodic myopathy/rhabdomyolysis with chronic complications such as peripheral neuropathy and retinopathy. Newborn screening (NBS) via tandem mass spectrometry (MS/MS) acylcarnitines is widely implemented but has variable positive predictive value and can miss milder/atypical cases. Current standard management is dietary and catabolic‑stress prevention; triheptanoin (C7 triglyceride) is used in long‑chain FAO disorders and is associated with reduced hospitalization/event burden in cohorts, while 2023–2024 translational work highlights cardiolipin remodeling defects and gene‑addition rescue strategies in retinal models. (neto2024mitochondrialbioenergeticsand pages 1-2, schwantje2022geneticbiochemicaland pages 2-2, stinton2021newbornscreeningfor pages 5-6, porta2024triheptanoininpatients pages 4-6, devine2024ipscderivedlchaddretinal pages 1-2)

1. Disease information

1.1 Definition and current understanding

MTPD is an inherited metabolic disorder in which mitochondrial long‑chain fatty‑acid β‑oxidation is impaired due to deficiency of the mitochondrial trifunctional protein complex. The complex catalyzes the final three steps of long‑chain β‑oxidation and is composed of α and β subunits. (fletcher2012observationsregardingretinopathy pages 1-2, schwantje2022geneticbiochemicaland pages 2-2)

A 2024 mechanistic study summarizes: “Mitochondrial trifunctional protein (TFP) deficiency is an inherited metabolic disorder leading to a block in long-chain fatty acid β-oxidation.” (neto2024mitochondrialbioenergeticsand pages 1-2)

1.2 Key identifiers (best available from retrieved sources)

MONDO: MONDO_0012172 “mitochondrial trifunctional protein deficiency” (Open Targets mapping). (OpenTargets Search: mitochondrial trifunctional protein deficiency)
OMIM: MTPD (complete/generalized) referenced as OMIM #609015 and isolated LCHAD deficiency referenced as OMIM #609016 in retrieved literature. (gaston2023ag1528chadha pages 1-2, fletcher2012observationsregardingretinopathy pages 1-2)
MeSH / ICD‑10 / ICD‑11: Not located in the retrieved full‑text evidence set for this run (should be confirmed in MeSH/ICD resources externally).

1.3 Synonyms / alternative names

Mitochondrial trifunctional protein deficiency (MTPD), trifunctional protein deficiency (TFP deficiency), generalized MTP deficiency
Related MTP disorders (often discussed together for screening/management): long‑chain 3‑hydroxyacyl‑CoA dehydrogenase deficiency (LCHADD/LCHAD deficiency) and long‑chain 3‑ketoacyl‑CoA thiolase deficiency (LCKATD). (schwantje2022geneticbiochemicaland pages 2-2, schwantje2022geneticbiochemicaland pages 1-2)

1.4 Evidence source type

Evidence in this report is drawn from aggregated disease resources (e.g., Open Targets disease mapping) plus human cohort studies/case series, newborn screening systematic reviews, and model systems (mouse and patient‑derived iPSC cellular models). (OpenTargets Search: mitochondrial trifunctional protein deficiency, stinton2021newbornscreeningfor pages 5-6, gaston2023ag1528chadha pages 1-2, devine2024ipscderivedlchaddretinal pages 1-2)

2. Etiology

2.1 Disease causal factors

Primary cause: biallelic pathogenic variants in HADHA and/or HADHB affecting the MTP complex. A 2024 paper states: “Mutations in HADHA and HADHB, which encode the TFP α and β subunits, respectively, usually result in combined TFP deficiency. A single common mutation, HADHA c.1528G>C … leads to isolated 3-hydroxyacyl-CoA dehydrogenase deficiency.” (neto2024mitochondrialbioenergeticsand pages 1-2)

Inheritance: autosomal recessive. (grunert2021thespectrumof pages 1-2, baydakova2023newacylcarnitineratio pages 1-2)

2.2 Risk factors

Genetic: having biallelic pathogenic variants in HADHA/HADHB. (neto2024mitochondrialbioenergeticsand pages 1-2, grunert2021thespectrumof pages 1-2)
Physiologic/environmental triggers (disease decompensation triggers rather than susceptibility loci): catabolic stress including fasting, illness, fever, and exercise. Later‑onset forms can manifest with episodic rhabdomyolysis triggered by fasting/exertion. (grunert2021thespectrumof pages 1-2, baydakova2023newacylcarnitineratio pages 1-2)

2.3 Protective factors

No validated genetic protective variants were identified in the retrieved evidence set. Prevention of crises is largely behavioral/medical (avoid fasting, prompt sick‑day management). (schwantje2022geneticbiochemicaland pages 2-2, kim2021triheptanoininthe pages 1-2)

2.4 Gene–environment interaction (GxE)

The clearest GxE pattern supported by retrieved evidence is thermo‑sensitivity and fever: variants leading to thermo‑sensitive enzymes can precipitate episodic myopathic decompensation when body temperature rises (e.g., during febrile illness). (grunert2021thespectrumof pages 1-2)

3. Phenotypes (clinical spectrum)

3.1 Core phenotype categories (with HPO suggestions)

Neonatal/infantile severe disease (symptoms/signs)
Hypoketotic hypoglycemia (HP:0001943 Hypoglycemia, HP:0002046 Hypoketonemia) (fletcher2012observationsregardingretinopathy pages 1-2, grunert2021thespectrumof pages 1-2)
Metabolic acidosis (HP:0001942 Metabolic acidosis) (grunert2021thespectrumof pages 1-2)
Cardiomyopathy/arrhythmia (HP:0001638 Cardiomyopathy, HP:0001649 Tachycardia/arrhythmia) (fletcher2012observationsregardingretinopathy pages 1-2, schwantje2022geneticbiochemicaland pages 1-2)
Liver dysfunction (HP:0001399 Hepatic failure, HP:0002910 Elevated transaminases) (fletcher2012observationsregardingretinopathy pages 1-2, grunert2021thespectrumof pages 1-2)
Infantile/childhood hepatic/cardiac phenotype
Recurrent metabolic decompensation with hypoglycemia and cardiomyopathy (schwantje2022geneticbiochemicaland pages 2-2, schwantje2022geneticbiochemicaland pages 1-2)
Later‑onset neuromyopathic phenotype
Exercise/illness‑triggered rhabdomyolysis (HP:0003236 Rhabdomyolysis, HP:0003201 Myoglobinuria) (fletcher2012observationsregardingretinopathy pages 1-2, grunert2021thespectrumof pages 1-2)
Myopathy/weakness (HP:0003198 Myopathy, HP:0001324 Muscle weakness) (grunert2021thespectrumof pages 1-2)
Peripheral neuropathy (HP:0009830 Peripheral neuropathy) (grunert2021thespectrumof pages 1-2)
Chronic complications (notably LCHADD‑predominant)
Pigmentary retinopathy/chorioretinopathy (HP:0001103 Abnormality of the retina, HP:0000486 Retinopathy) (fletcher2012observationsregardingretinopathy pages 1-2)
Progressive peripheral neuropathy (HP:0009830) (grunert2021thespectrumof pages 1-2)

3.2 Frequency and phenotype statistics from cohorts/series

Peripheral neuropathy prevalence: overall 58% in one cohort (8 LCHADD; 11 MTPD), with 70% in MTPD vs 50% in LCHADD; median onset earlier in MTPD (4.7 vs 15.3 years, P=0.047). (grunert2021thespectrumof pages 1-2)
Neuropathy phenotype distribution: 45.5% sensorimotor, 27.3% pure motor, 27.3% isolated sensory. (grunert2021thespectrumof pages 1-2)
Retinopathy frequency (LCHADD): “In 30 to greater than 50% of cases of isolated LCHAD deficiency” with pigment changes evident by age 2 in “around 50%.” (fletcher2012observationsregardingretinopathy pages 1-2)
MTPD vs LCHADD retinopathy/neuropathy contrast: TFPD long‑term neuropathy “up to 80%,” retinopathy with vision loss “5–13%.” (fletcher2012observationsregardingretinopathy pages 1-2)
Dutch NBS era cohort: 13 patients (7 LCHADD, 5 MTPD, 1 LCKATD). Four MTPD and the single LCKATD developed cardiomyopathy and died in early life; among LCHADD, “Five LCHADD patients developed subclinical neuropathy and/or retinopathy.” (schwantje2022geneticbiochemicaland pages 1-2, schwantje2022geneticbiochemicaland pages 2-2)

3.3 Quality of life impacts (supported proxy endpoints)

Direct QoL instruments specific to MTPD were not prominent in the retrieved primary cohort papers. However, triheptanoin trials in LC‑FAOD report improvements in patient‑reported outcomes (SF‑12v2) alongside reduced event burden. (kim2021triheptanoininthe pages 4-5)

4. Genetic / molecular information

4.1 Causal genes

HADHA (TFP α‑subunit; includes LCHAD and LCEH activities) (schwantje2022geneticbiochemicaland pages 2-2)
HADHB (TFP β‑subunit; includes long‑chain ketoacyl‑CoA thiolase activity) (schwantje2022geneticbiochemicaland pages 2-2)

4.2 Pathogenic variants and variant classes (examples from retrieved sources)

Common founder variant for isolated LCHADD: HADHA c.1528G>C (reported as p.E510Q or p.Glu510Gln in retrieved sources), stated to represent ~87% of alleles in isolated LCHAD deficiency in one 2024 source and ~90% in European patients in another. (neto2024mitochondrialbioenergeticsand pages 1-2, baydakova2023newacylcarnitineratio pages 1-2)
Frameshift (loss‑of‑function) example: HADHB c.1059del (p.Gly354AspfsTer10) (compound heterozygous context in siblings). (schwantje2022geneticbiochemicaland pages 2-2)
Deep intronic/splicing example: HADHB c.1390‑515_1390‑499del causing pseudoexon inclusion with premature termination codon. (schwantje2022geneticbiochemicaland pages 2-2)
Thermo‑sensitive variant example: HADHA c.2132C>T (p.Pro711Leu) associated with fever‑triggered episodes; enzyme activity and protein expression diminished at 40°C vs 37°C in fibroblasts. (grunert2021thespectrumof pages 1-2)

4.3 Genotype–phenotype correlations (high level)

Homozygosity for HADHA c.1528G>C is used to classify isolated LCHADD, while other biallelic combinations in HADHA or HADHB more often yield generalized MTPD (with different complication patterns and earlier neuropathy). (grunert2021thespectrumof pages 1-2, neto2024mitochondrialbioenergeticsand pages 1-2)

4.4 Modifier genes / epigenetics / chromosomal abnormalities

No validated modifier genes, epigenetic signatures, or recurrent chromosomal structural variants were identified in the retrieved evidence set.

5. Environmental information

Environmental causes are not supported (Mendelian disorder), but environmental/physiologic triggers (fasting, illness, fever, exercise) are strongly implicated in triggering decompensation and rhabdomyolysis, especially in milder/thermo‑sensitive forms. (grunert2021thespectrumof pages 1-2, baydakova2023newacylcarnitineratio pages 1-2)

6. Mechanism / pathophysiology (with ontology suggestions)

6.1 Canonical causal chain (upstream → downstream)

Biallelic HADHA/HADHB variants → reduced MTP complex stability and/or enzymatic activities (LCEH/LCHAD/LCKAT) (grunert2021thespectrumof pages 1-2, neto2024mitochondrialbioenergeticsand pages 1-2)
Block in long‑chain fatty‑acid β‑oxidation → reduced energy production/ketogenesis and accumulation of long‑chain hydroxyacyl intermediates (fletcher2012observationsregardingretinopathy pages 1-2, devine2024ipscderivedlchaddretinal pages 1-2)
Accumulation/export of long‑chain 3‑hydroxyacylcarnitines detectable in blood spots (biomarker) and potentially toxic to tissues (heart, nerve, retina) (baydakova2023newacylcarnitineratio pages 1-2, devine2024ipscderivedlchaddretinal pages 1-2)
Tissue vulnerability under fasting/illness/exercise → metabolic crises, cardiomyopathy/arrhythmias, rhabdomyolysis; chronic retinal/nerve injury in many patients (fletcher2012observationsregardingretinopathy pages 1-2, grunert2021thespectrumof pages 1-2)

6.2 Recent mechanistic developments (2023–2024 prioritized)

(A) Cardiolipin remodeling and bioenergetics (2024) A 2024 JCI Insight study links MTP deficiency to cardiolipin (CL) remodeling defects: “TFP also catalyzes a step in the remodeling of cardiolipin (CL),” and in patient fibroblasts “CL reduction was universally identified” with variable MLCL changes and variable oxygen consumption phenotypes. (neto2024mitochondrialbioenergeticsand pages 1-2)

A key figure set showing quantitative CL/MLCL metrics and mitochondrial respiration phenotyping is available from this paper (Figure panels retrieved). (neto2024mitochondrialbioenergeticsand media cb4f3939, neto2024mitochondrialbioenergeticsand media e05c4916)

GO term suggestions (mechanism): - GO:0006635 fatty acid beta‑oxidation - GO:0005739 mitochondrion - GO:0004623 / cardiolipin remodeling-related processes (exact GO term mapping should be validated; the concept is supported by the MLCLAT activity link) (neto2024mitochondrialbioenergeticsand pages 1-2)

(B) Retinal pigment epithelium (RPE) lipid peroxidation + gene‑addition rescue (2024) A 2024 iPSC‑RPE study reports that LCHADD‑RPE “cannot oxidize palmitate, and release fewer ketones than WT-RPE,” show DHA‑induced oxidative stress and lipid peroxidation with decreased viability, and are “rescued by antioxidant agents.” It further demonstrates proof‑of‑concept gene addition: AAV‑HADHA delivery reduced hydroxyacylcarnitine accumulation and improved oxidative‑stress resistance. (devine2024ipscderivedlchaddretinal pages 1-2)

GO term suggestions (mechanism): - lipid peroxidation (GO mapping should be validated), oxidative stress response

Cell type (CL) suggestions: - CL:0000066 retinal pigment epithelial cell (supported conceptually by the iPSC‑RPE model) (devine2024ipscderivedlchaddretinal pages 1-2)

6.3 Biochemical abnormalities (diagnostic / mechanistic)

Elevated long‑chain hydroxyacylcarnitines (e.g., C16‑OH, C18:1‑OH) used for screening. (lotzhavla2018fatalpitfallsin pages 1-2)
Proposed 2023 biomarker: HADHA ratio = (C16OH + C18OH + C18:1OH) / C0, elevated in all 54 confirmed patients in one study. (baydakova2023newacylcarnitineratio pages 1-2)

7. Anatomical structures affected

7.1 Organ/system level (UBERON suggestions)

Heart (UBERON:0000948): cardiomyopathy/arrhythmia; early mortality in severe MTPD/LCKATD. (schwantje2022geneticbiochemicaland pages 1-2)
Liver (UBERON:0002107): hepatic dysfunction/failure in severe forms and some LCHADD presentations. (fletcher2012observationsregardingretinopathy pages 1-2)
Skeletal muscle (UBERON:0001134): episodic myopathy/rhabdomyolysis. (grunert2021thespectrumof pages 1-2)
Peripheral nervous system (UBERON:0000010 concept): peripheral neuropathy as common chronic complication. (grunert2021thespectrumof pages 1-2)
Eye/retina/RPE (UBERON:0000966 retina; RPE concept): progressive retinopathy/chorioretinopathy; mechanistic vulnerability in RPE models. (fletcher2012observationsregardingretinopathy pages 1-2, devine2024ipscderivedlchaddretinal pages 1-2)

7.2 Subcellular compartments (GO cellular component suggestions)

Mitochondrion (GO:0005739)
Mitochondrial inner membrane (GO:0005743), relevant to cardiolipin remodeling and respiratory chain organization (neto2024mitochondrialbioenergeticsand pages 1-2)

8. Temporal development (natural history)

Onset: ranges from neonatal/early‑infantile to childhood/adult. (fletcher2012observationsregardingretinopathy pages 1-2, grunert2021thespectrumof pages 1-2)
Progression/course:
Severe forms can lead to early death from cardiomyopathy/metabolic crisis (Dutch cohort: deaths within 1 month to 13 months for MTPD/LCKATD with cardiomyopathy). (schwantje2022geneticbiochemicaland pages 1-2)
Later‑onset forms are often episodic (rhabdomyolysis episodes) with risk of progressive/irreversible neuropathy and retinopathy despite early diagnosis and treatment. (grunert2021thespectrumof pages 1-2)

9. Inheritance and population

9.1 Epidemiology (best available from retrieved sources)

LCHADD incidence in European populations reported as <1.5 per 100,000 births in one 2023 study context. (baydakova2023newacylcarnitineratio pages 1-2)
Screening paper cites live prevalence ~1:140,000 for MTP/LCHAD deficiency. (lotzhavla2018fatalpitfallsin pages 1-2)

9.2 Population genetics / founder effects

The retrieved evidence emphasizes the high frequency of the recurrent HADHA c.1528G>C allele in European LCHADD, but detailed geographic/founder breakdowns were not consistently available across primary studies in this run. (neto2024mitochondrialbioenergeticsand pages 1-2, baydakova2023newacylcarnitineratio pages 1-2)

10. Diagnostics

10.1 Core diagnostic tests and biomarkers (real‑world implementation)

Newborn screening (NBS)
MS/MS acylcarnitine profiling in dried blood spots; commonly cited primary markers include C16‑OH and C18:1‑OH. (lotzhavla2018fatalpitfallsin pages 1-2)
Limitation: “screening may not identify some patients” noted in retinopathy-focused clinical review. (fletcher2012observationsregardingretinopathy pages 1-2)
Confirmatory testing
Evidence highlights pitfalls of relying only on plasma acylcarnitines and urine organic acids: “analyses of acylcarnitines in blood and organic acids in urine alone are not suitable for confirmatory testing,” with missed cases described when urine organic acids were normal. (lotzhavla2018fatalpitfallsin pages 1-2)
Confirmatory workup often requires molecular testing (HADHA/HADHB) and/or functional enzyme studies. (schwantje2022geneticbiochemicaland pages 2-2)
Improved biochemical metric (2023)
HADHA ratio (C16OH + C18OH + C18:1OH)/C0 elevated in all 54 confirmed patients in one study, proposed to reduce false negatives. (baydakova2023newacylcarnitineratio pages 1-2)

10.2 NBS test accuracy statistics

A systematic review of NBS test accuracy (acylcarnitines in dried blood spots) reported: - ~4,000,000 babies screened, 23 cases identified (11 reported as LCHAD) (stinton2021newbornscreeningfor pages 5-6) - Positive predictive value (PPV) range 0% to 100%, with specific examples: - 0% PPV: 0 true positives, 28 false positives / 276,565 screened - 100% PPV: 13 true positives, 0 false positives / 2,037,824 screened (stinton2021newbornscreeningfor pages 5-6) - Sensitivity/specificity/NPV were not calculable due to lack of systematic follow‑up of screen‑negative infants. (stinton2021newbornscreeningfor pages 5-6, stinton2021newbornscreeningfor pages 1-2)

10.3 Differential diagnosis

Not comprehensively extracted in this run; however, screening pitfalls literature notes false positives can occur in NICU/preterm contexts and emphasizes specialized metabolic evaluation. (stinton2021newbornscreeningfor pages 1-2, lotzhavla2018fatalpitfallsin pages 1-2)

11. Outcomes / prognosis

Outcomes are highly variable; Dutch cohort data illustrate severe early mortality in generalized MTP deficiencies with cardiomyopathy (“Four MTPD patients and one LCKATD patient developed cardiomyopathy and died within 1 month and 13 months of life, respectively.”) (schwantje2022geneticbiochemicaland pages 1-2)
Even with early diagnosis and therapy, chronic complications may persist: neuropathy may not be preventable in all cases (“Despite early diagnosis by newborn screening and early initiation of therapy, peripheral neuropathy cannot be prevented in all patients… and has severe impact on the life of affected patients.”) (grunert2021thespectrumof pages 1-2)

12. Treatment

12.1 Standard management (current practice)

Avoid fasting and catabolic stress; prompt sick‑day/emergency carbohydrate provision.
Dietary long‑chain triglyceride restriction and supplementation with medium‑chain triglycerides (MCT) is the historical standard, but does not eliminate symptoms and does not reliably prevent long‑term complications. (kim2021triheptanoininthe pages 1-2, schwantje2022geneticbiochemicaland pages 2-2)

MAXO suggestions (conceptual, for curation): dietary fat modification; avoidance of fasting; emergency management of metabolic crisis.

12.2 Triheptanoin (Dojolvi/UX007) — evidence and implementation

Mechanism/role: an odd‑chain triglyceride providing acetyl‑CoA and propionyl‑CoA (anaplerosis), used for LC‑FAODs including LCHAD/TFP defects. (kim2021triheptanoininthe pages 1-2, NCT01379625 chunk 1)

Dosing in real-world cohort (Italy, retrospective; publication Oct 2024, URL: https://doi.org/10.1186/s13052-024-01782-y): - Mean dose 1.5 ± 0.9 g/kg/day in four divided administrations, providing 23.9 ± 8.9% of daily calories; treatment duration 2.2 ± 0.9 years. (porta2024triheptanoininpatients pages 1-2)

Outcome statistics (Italy cohort; triheptanoin vs prior MCT): - Intercurrent catabolic episodes 4.3 ± 5.3 vs 22.0 ± 22.2 (p=0.034) - Hospitalized metabolic decompensations 2.0 ± 2.5 vs 18.3 ± 17.7 (p=0.014) - CK outside decompensation decreased (828 ± 1238 → 274 ± 242 UI/L; p=0.207); CK during decompensation decreased (66,178 ± 57,565 → 30,550 ± 24,958 IU/L; p=0.218) - No ICU admissions during triheptanoin treatment; GI adverse effects reported (epigastric pain, diarrhea). (porta2024triheptanoininpatients pages 4-6)

Trial‑level effect sizes (summarized in 2021 profile; CL201 severe LC‑FAOD; URL: https://doi.org/10.1007/s40267-021-00816-3): - Major clinical event rate reduction 48.1% (1.69 → 0.88 events/year; p=0.021) - Hospitalization event rate reduction 53.1% (1.39 → 0.65 events/year; p=0.016) - Hospitalization duration reduction 51.5% (5.66 → 2.74 days/year; p=0.032) (kim2021triheptanoininthe pages 4-5)

12.3 Clinical trials (applications / real-world pipeline)

NCT01379625 (OHSU; randomized, double‑masked phase 2): triheptanoin vs MCT, 20% energy for 4 months; inclusion includes confirmed TFP or LCHAD deficiency among LC‑FAODs; endpoints include energy expenditure and ejection fraction change. (NCT01379625 chunk 1)
NCT01886378 (Ultragenyx; open‑label phase 2): triheptanoin titrated to 25–35% caloric intake, 24‑week primary period with extension to 78 weeks; includes LCHAD and other LC‑FAODs; functional exercise endpoints. (NCT01886378 chunk 1)
NCT05933200 (Ultragenyx; phase 3, quadruple‑masked pediatric): triheptanoin vs even‑chain MCT; primary endpoint annualized major clinical event rate; includes LCHAD/TFP defects. (NCT05933200 chunk 1)
NCT02214160 (extension; open‑label): long‑term MCE rate and safety (TEAEs/serious TEAEs). (NCT02214160 chunk 1)

12.4 Emerging/experimental therapeutics (2024 translational)

AAV-HADHA gene addition showed rescue of metabolic and oxidative‑stress phenotypes in patient‑derived iPSC‑RPE, supporting a potential therapy for LCHADD-associated chorioretinopathy (preclinical proof‑of‑concept). (devine2024ipscderivedlchaddretinal pages 1-2)

13. Prevention

Primary prevention: not applicable in the classic public‑health sense for a Mendelian disorder, but carrier screening, prenatal testing, and genetic counseling are standard preventive strategies.
Secondary prevention: NBS enables pre‑symptomatic dietary management; however, evidence shows NBS can miss cases and has variable PPV, so programs consider improved ratios/second‑tier methods. (stinton2021newbornscreeningfor pages 5-6, baydakova2023newacylcarnitineratio pages 1-2, lotzhavla2018fatalpitfallsin pages 1-2)
Tertiary prevention: prevention of metabolic crises via fasting avoidance/sick‑day protocols and potentially triheptanoin to reduce event burden. (porta2024triheptanoininpatients pages 4-6, kim2021triheptanoininthe pages 4-5)

14. Other species / natural disease

No naturally occurring veterinary disease associations were identified in the retrieved evidence set.

15. Model organisms and experimental systems

15.1 Mouse model (2023)

A CRISPR/Cas9 Hadha G1528C knock‑in mouse models the common human LCHADD allele and recapitulates key phenotypes: lower fasting ketones, accumulation of plasma 3‑hydroxyacylcarnitines, earlier treadmill exhaustion, dilated cardiomyopathy, and retinal/RPE dysfunction with reduced cone function. (gaston2023ag1528chadha pages 1-2)

15.2 Human iPSC cellular model (2024)

Patient‑derived iPSC‑RPE shows impaired palmitate oxidation and heightened DHA‑induced lipid peroxidation, reversible with antioxidants and with AAV‑HADHA gene addition (proof‑of‑concept). (devine2024ipscderivedlchaddretinal pages 1-2)

Structured summary table

Category	Summary
Disease / identifiers	Mitochondrial trifunctional protein deficiency (MTPD); MONDO MONDO:0012172 from Open Targets disease mapping. Related subtype entries in retrieved sources: MTP deficiency / complete MTP deficiency OMIM 609015 and isolated LCHAD deficiency OMIM 609016; LCHADD is treated as an MTP-related deficiency in screening/clinical papers. MeSH/ICD: not found in retrieved sources. Data here are from aggregated disease resources plus patient/cohort studies, not EHR-only sources (OpenTargets Search: mitochondrial trifunctional protein deficiency, neto2024mitochondrialbioenergeticsand pages 1-2, schwantje2022geneticbiochemicaland pages 2-2)
Causal genes / inheritance / major variants	Autosomal recessive disease caused by biallelic variants in HADHA (TFP α-subunit; LCEH/LCHAD activities) or HADHB (TFP β-subunit; LCKAT activity). Most HADHA and all HADHB pathogenic variants usually cause generalized MTP deficiency; recurrent HADHA c.1528G>C (reported as p.E510Q / p.Glu510Gln in retrieved sources) causes isolated LCHAD deficiency and accounts for ~87% of alleles in isolated LCHADD in one 2024 review and ~90% of European patients in another source. Recent examples include HADHB c.1059del plus deep intronic HADHB c.1390-515_1390-499del causing aberrant splicing, HADHA p.Pro711Leu thermo-sensitive disease, and HADHB c.1175C>T adult neuropathic disease (neto2024mitochondrialbioenergeticsand pages 1-2, baydakova2023newacylcarnitineratio pages 1-2, grunert2021thespectrumof pages 1-2, schwantje2022geneticbiochemicaland pages 2-2)
Core biochemical biomarkers (NBS / diagnosis)	Newborn screening and diagnostic workup rely on tandem MS acylcarnitine profiling in dried blood spots with elevated long-chain hydroxyacylcarnitines, especially C16-OH and C18:1-OH; broader marker set reported includes C14-OH, C14:1-OH, C16-OH, C16:1-OH, C18-OH, C18:1-OH. A newer 2023 diagnostic metric is the “HADHA ratio” = (C16OH + C18OH + C18:1OH) / C0, which was elevated in all 54 confirmed LCHAD/MTP patients and not elevated in 19 VLCAD patients, improving sensitivity/specificity versus standard acylcarnitines alone. Confirmatory diagnosis may require enzymatic and molecular testing because plasma/urine biochemistry alone can miss cases (baydakova2023newacylcarnitineratio pages 1-2, lotzhavla2018fatalpitfallsin pages 1-2, schwantje2022geneticbiochemicaland pages 2-2)
Key phenotypic subtypes	Severe neonatal/infantile form: hypoketotic hypoglycemia, metabolic acidosis, liver dysfunction, cardiomyopathy, arrhythmia/sudden death. Infantile hepatic/cardiomyopathic form: recurrent decompensation, hypoglycemia, cardiomyopathy. Later-onset neuromyopathic form: exercise/fasting/fever-triggered rhabdomyolysis, myopathy, peripheral neuropathy; thermo-sensitive forms may have near-normal acylcarnitines at baseline and episodic myopathy with fever. LCHADD-specific chronic complications: chorioretinopathy/retinopathy more prominent. MTPD: neuropathy more prominent than vision loss. Adult CNS involvement has also been reported (grunert2021thespectrumof pages 1-2, schwantje2022geneticbiochemicaland pages 2-2, fletcher2012observationsregardingretinopathy pages 1-2, devine2024ipscderivedlchaddretinal pages 11-12, gaston2023ag1528chadha pages 1-2)
Major complications / frequencies	Peripheral neuropathy: overall prevalence 58% in one cohort; 70% in MTPD vs 50% in LCHADD; median onset 4.7 y vs 15.3 y respectively. Neuropathy subtypes: 45.5% sensorimotor, 27.3% pure motor, 27.3% isolated sensory. Retinopathy: in isolated LCHADD, irreversible retinopathy reported in 30% to >50% of cases, with pigment changes by age 2 in ~50%; peripheral neuropathy in older LCHADD reports ~5–10%. In TFPD, neuropathy may occur in up to 80% long term, while retinopathy with vision loss reported in 5–13%. In the Dutch post-NBS cohort, 5/7 LCHADD patients developed subclinical neuropathy and/or retinopathy. Cardiomyopathy mortality: 4/5 MTPD patients and 1/1 LCKATD patient in the Dutch cohort developed cardiomyopathy and died within 1 month to 13 months of life (grunert2021thespectrumof pages 1-2, fletcher2012observationsregardingretinopathy pages 1-2, schwantje2022geneticbiochemicaland pages 2-2, schwantje2022geneticbiochemicaland pages 1-2)
Epidemiology / screening performance	Retrieved prevalence estimates include <1.5 per 100,000 births for LCHADD in European populations and ~1:140,000 live births for MTP/LCHAD deficiency in one screening paper. NBS performance is variable: systematic review identified 23 babies with LCHAD/MTP deficiencies across ~4 million screened newborns, with PPV ranging from 0% (0 true positives, 28 false positives / 276,565 screened) to 100% (13 true positives / 2,037,824 screened). Sensitivity/specificity/NPV could not be calculated because negatives were not systematically followed. False negatives and missed mild cases occur, especially with normal or only mildly abnormal acylcarnitines (stinton2021newbornscreeningfor pages 5-6, stinton2021newbornscreeningfor pages 1-2, lotzhavla2018fatalpitfallsin pages 1-2, schwantje2022geneticbiochemicaland pages 2-2)
Current standard management	Standard care centers on avoidance of fasting, prevention of catabolic stress, long-chain fat restriction, and medium-chain triglyceride (MCT) supplementation; emergency feeding during illness is important. Current treatment can reduce hypoglycemia risk but often does not prevent cardiomyopathy or later neuropathy/retinopathy. Some reports mention carnitine use and monitoring of free carnitine/acylcarnitines, but benefit remains individualized in retrieved sources (kim2021triheptanoininthe pages 1-2, kochan2025howgenesmeet pages 7-9, schwantje2022geneticbiochemicaland pages 2-2)
Triheptanoin / treatment outcomes	Triheptanoin is an approved odd-chain MCT for LC-FAODs including LCHAD/TFP-related disease; typical target 25–35% of total daily calories, given in ≥4 divided doses. In a 2024 Italian LC-FAOD cohort switching from MCT to triheptanoin, mean dose was 1.5 ± 0.9 g/kg/day, providing 23.9 ± 8.9% of calories; intercurrent catabolic episodes fell from 22.0 ± 22.2 to 4.3 ± 5.3 (p=0.034), hospitalized metabolic decompensations from 18.3 ± 17.7 to 2.0 ± 2.5 (p=0.014), with lower non-decompensation CK in 7 patients and no ICU admissions on treatment. In CL201 summarized in a 2021 profile, triheptanoin reduced mean annualized major clinical event rate by 48.1% (1.69 to 0.88 events/year; p=0.021) and hospitalization event rate by 53.1% (1.39 to 0.65/year; p=0.016). GI adverse effects (diarrhea, epigastric pain) are the most common. Severe neonatal cardiomyopathy may still fail to respond in some cases (porta2024triheptanoininpatients pages 1-2, porta2024triheptanoininpatients pages 4-6, kim2021triheptanoininthe pages 4-5, kim2021triheptanoininthe pages 1-2, NCT01886378 chunk 1, NCT02214160 chunk 1)
Recent mechanistic / translational developments (2023–2024)	2024 JCI Insight: patient fibroblasts showed universal cardiolipin reduction with variable monolysocardiolipin increase and heterogeneous bioenergetic impairment, linking MTP deficiency to defective cardiolipin remodeling and genotype-dependent mitochondrial dysfunction. 2024 iPSC-RPE model: LCHADD RPE cells accumulated 3-hydroxyacylcarnitines, failed to oxidize palmitate, released fewer ketones, and were vulnerable to DHA-induced oxidative stress/lipid peroxidation; antioxidant rescue and AAV-HADHA gene addition improved these defects. 2023 knock-in mouse: Hadha G1528C mice recapitulated lower fasting ketones, plasma 3-hydroxyacylcarnitine accumulation, dilated cardiomyopathy, retinal dysfunction, and motor deficits (neto2024mitochondrialbioenergeticsand pages 1-2, devine2024ipscderivedlchaddretinal pages 11-12, devine2024ipscderivedlchaddretinal pages 1-2, gaston2023ag1528chadha pages 1-2, neto2024mitochondrialbioenergeticsand media cb4f3939)

Table: This table condenses the most actionable evidence for mitochondrial trifunctional protein deficiency, including identifiers, genetics, diagnostic biomarkers, major phenotypes, complication frequencies, and current treatment data. It is designed as a quick-reference artifact for building a structured disease knowledge base entry.

Figures (visual evidence)

Quantitative cardiolipin/monolysocardiolipin remodeling and mitochondrial respiration phenotyping in MTP‑deficient patient fibroblasts (JCI Insight 2024; figure panels retrieved). (neto2024mitochondrialbioenergeticsand media cb4f3939, neto2024mitochondrialbioenergeticsand media e05c4916)

Notes on gaps / items not resolved in this tool-assisted run

ICD/MeSH identifiers were not located in the retrieved evidence set; they should be verified via OMIM/Orphanet/MeSH/ICD resources.
Maternal AFLP/HELLP association is widely discussed in the broader literature for fetal FAO disorders, but primary sources specifically evidencing this association were not successfully incorporated into the citeable evidence set in this run.

References

(neto2024mitochondrialbioenergeticsand pages 1-2): Eduardo Vieira Neto, Meicheng Wang, Austin J. Szuminsky, Lethicia Ferraro, Erik Koppes, Yudong Wang, Clinton Van’t Land, Al-Walid Mohsen, Geancarlo Zanatta, Areeg H. El-Gharbawy, Tamil S. Anthonymuthu, Yulia Y. Tyurina, Vladimir A. Tyurin, Valerian Kagan, Hülya Bayır, and Jerry Vockley. Mitochondrial bioenergetics and cardiolipin remodeling abnormalities in mitochondrial trifunctional protein deficiency. JCI Insight, Sep 2024. URL: https://doi.org/10.1172/jci.insight.176887, doi:10.1172/jci.insight.176887. This article has 16 citations and is from a domain leading peer-reviewed journal.
(schwantje2022geneticbiochemicaland pages 2-2): Marit Schwantje, Sabine A. Fuchs, Lonneke de Boer, Annet M. Bosch, Inge Cuppen, Eugenie Dekkers, Terry G. J. Derks, Sacha Ferdinandusse, Lodewijk Ijlst, Riekelt H. Houtkooper, Rose Maase, W. Ludo van der Pol, Maaike C. de Vries, Rendelien K. Verschoof‐Puite, Ronald J. A. Wanders, Monique Williams, Frits Wijburg, and Gepke Visser. Genetic, biochemical, and clinical spectrum of patients with mitochondrial trifunctional protein deficiency identified after the introduction of newborn screening in the netherlands. Journal of Inherited Metabolic Disease, 45:804-818, Apr 2022. URL: https://doi.org/10.1002/jimd.12502, doi:10.1002/jimd.12502. This article has 18 citations and is from a peer-reviewed journal.
(stinton2021newbornscreeningfor pages 5-6): Chris Stinton, Hannah Fraser, Julia Geppert, Rebecca Johnson, Martin Connock, Samantha Johnson, Aileen Clarke, and Sian Taylor-Phillips. Newborn screening for long-chain 3-hydroxyacyl-coa dehydrogenase and mitochondrial trifunctional protein deficiencies using acylcarnitines measurement in dried blood spots—a systematic review of test accuracy. Frontiers in Pediatrics, Mar 2021. URL: https://doi.org/10.3389/fped.2021.606194, doi:10.3389/fped.2021.606194. This article has 15 citations.
(porta2024triheptanoininpatients pages 4-6): Francesco Porta, Arianna Maiorana, Vincenza Gragnaniello, Elena Procopio, Serena Gasperini, Roberta Taurisano, Marco Spada, Carlo Dionisi-Vici, and Alberto Burlina. Triheptanoin in patients with long-chain fatty acid oxidation disorders: clinical experience in italy. Italian Journal of Pediatrics, Oct 2024. URL: https://doi.org/10.1186/s13052-024-01782-y, doi:10.1186/s13052-024-01782-y. This article has 11 citations and is from a peer-reviewed journal.
(devine2024ipscderivedlchaddretinal pages 1-2): Tiffany DeVine, Gabriela Elizondo, Garen Gaston, Shannon J. Babcock, Dietrich Matern, Mikhail S. Shchepinov, Mark E. Pennesi, Cary O. Harding, and Melanie B. Gillingham. Ipsc-derived lchadd retinal pigment epithelial cells are susceptible to lipid peroxidation and rescued by transfection of a wildtype aav-hadha vector. Investigative Ophthalmology & Visual Science, 65:22, Sep 2024. URL: https://doi.org/10.1167/iovs.65.11.22, doi:10.1167/iovs.65.11.22. This article has 3 citations and is from a domain leading peer-reviewed journal.
(fletcher2012observationsregardingretinopathy pages 1-2): Autumn L. Fletcher, Mark E. Pennesi, Cary O. Harding, Richard G. Weleber, and Melanie B. Gillingham. Observations regarding retinopathy in mitochondrial trifunctional protein deficiencies. Molecular genetics and metabolism, 106 1:18-24, May 2012. URL: https://doi.org/10.1016/j.ymgme.2012.02.015, doi:10.1016/j.ymgme.2012.02.015. This article has 90 citations and is from a peer-reviewed journal.
(OpenTargets Search: mitochondrial trifunctional protein deficiency): Open Targets Query (mitochondrial trifunctional protein deficiency, 10 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.
(gaston2023ag1528chadha pages 1-2): Garen Gaston, Shannon Babcock, Renee Ryals, Gabriela Elizondo, Tiffany DeVine, Dahlia Wafai, William Packwood, Sarah Holden, Jacob Raber, Jonathan R. Lindner, Mark E. Pennesi, Cary O. Harding, and Melanie B. Gillingham. A g1528c hadha knock-in mouse model recapitulates aspects of human clinical phenotypes for long-chain 3-hydroxyacyl-coa dehydrogenase deficiency. Communications Biology, Aug 2023. URL: https://doi.org/10.1038/s42003-023-05268-1, doi:10.1038/s42003-023-05268-1. This article has 15 citations and is from a peer-reviewed journal.
(schwantje2022geneticbiochemicaland pages 1-2): Marit Schwantje, Sabine A. Fuchs, Lonneke de Boer, Annet M. Bosch, Inge Cuppen, Eugenie Dekkers, Terry G. J. Derks, Sacha Ferdinandusse, Lodewijk Ijlst, Riekelt H. Houtkooper, Rose Maase, W. Ludo van der Pol, Maaike C. de Vries, Rendelien K. Verschoof‐Puite, Ronald J. A. Wanders, Monique Williams, Frits Wijburg, and Gepke Visser. Genetic, biochemical, and clinical spectrum of patients with mitochondrial trifunctional protein deficiency identified after the introduction of newborn screening in the netherlands. Journal of Inherited Metabolic Disease, 45:804-818, Apr 2022. URL: https://doi.org/10.1002/jimd.12502, doi:10.1002/jimd.12502. This article has 18 citations and is from a peer-reviewed journal.
(grunert2021thespectrumof pages 1-2): Sarah C. Grünert, Matthias Eckenweiler, Dorothea Haas, Martin Lindner, Konstantinos Tsiakas, René Santer, Sara Tucci, and Ute Spiekerkoetter. The spectrum of peripheral neuropathy in disorders of the mitochondrial trifunctional protein. Journal of Inherited Metabolic Disease, 44:893-902, Mar 2021. URL: https://doi.org/10.1002/jimd.12372, doi:10.1002/jimd.12372. This article has 32 citations and is from a peer-reviewed journal.
(baydakova2023newacylcarnitineratio pages 1-2): Galina V. Baydakova, Polina G. Tsygankova, Natalia L. Pechatnikova, Olga A. Bazhanova, Yana D. Nazarenko, and Ekaterina Y. Zakharova. New acylcarnitine ratio as a reliable indicator of long-chain 3-hydroxyacyl-coa dehydrogenase deficiency. International Journal of Neonatal Screening, 9:48, Aug 2023. URL: https://doi.org/10.3390/ijns9030048, doi:10.3390/ijns9030048. This article has 7 citations.
(kim2021triheptanoininthe pages 1-2): Esther S. Kim and Susan J. Keam. Triheptanoin in the management of long-chain fatty acid oxidation disorders: a profile of its use. Drugs & Therapy Perspectives, 37:187-193, Mar 2021. URL: https://doi.org/10.1007/s40267-021-00816-3, doi:10.1007/s40267-021-00816-3. This article has 7 citations and is from a peer-reviewed journal.
(kim2021triheptanoininthe pages 4-5): Esther S. Kim and Susan J. Keam. Triheptanoin in the management of long-chain fatty acid oxidation disorders: a profile of its use. Drugs & Therapy Perspectives, 37:187-193, Mar 2021. URL: https://doi.org/10.1007/s40267-021-00816-3, doi:10.1007/s40267-021-00816-3. This article has 7 citations and is from a peer-reviewed journal.
(neto2024mitochondrialbioenergeticsand media cb4f3939): Eduardo Vieira Neto, Meicheng Wang, Austin J. Szuminsky, Lethicia Ferraro, Erik Koppes, Yudong Wang, Clinton Van’t Land, Al-Walid Mohsen, Geancarlo Zanatta, Areeg H. El-Gharbawy, Tamil S. Anthonymuthu, Yulia Y. Tyurina, Vladimir A. Tyurin, Valerian Kagan, Hülya Bayır, and Jerry Vockley. Mitochondrial bioenergetics and cardiolipin remodeling abnormalities in mitochondrial trifunctional protein deficiency. JCI Insight, Sep 2024. URL: https://doi.org/10.1172/jci.insight.176887, doi:10.1172/jci.insight.176887. This article has 16 citations and is from a domain leading peer-reviewed journal.
(neto2024mitochondrialbioenergeticsand media e05c4916): Eduardo Vieira Neto, Meicheng Wang, Austin J. Szuminsky, Lethicia Ferraro, Erik Koppes, Yudong Wang, Clinton Van’t Land, Al-Walid Mohsen, Geancarlo Zanatta, Areeg H. El-Gharbawy, Tamil S. Anthonymuthu, Yulia Y. Tyurina, Vladimir A. Tyurin, Valerian Kagan, Hülya Bayır, and Jerry Vockley. Mitochondrial bioenergetics and cardiolipin remodeling abnormalities in mitochondrial trifunctional protein deficiency. JCI Insight, Sep 2024. URL: https://doi.org/10.1172/jci.insight.176887, doi:10.1172/jci.insight.176887. This article has 16 citations and is from a domain leading peer-reviewed journal.
(lotzhavla2018fatalpitfallsin pages 1-2): Amelie S. Lotz-Havla, Wulf Röschinger, Katharina Schiergens, Katharina Singer, Daniela Karall, Vassiliki Konstantopoulou, Saskia B. Wortmann, and Esther M. Maier. Fatal pitfalls in newborn screening for mitochondrial trifunctional protein (mtp)/long-chain 3-hydroxyacyl-coa dehydrogenase (lchad) deficiency. Orphanet Journal of Rare Diseases, Jul 2018. URL: https://doi.org/10.1186/s13023-018-0875-6, doi:10.1186/s13023-018-0875-6. This article has 31 citations and is from a peer-reviewed journal.
(stinton2021newbornscreeningfor pages 1-2): Chris Stinton, Hannah Fraser, Julia Geppert, Rebecca Johnson, Martin Connock, Samantha Johnson, Aileen Clarke, and Sian Taylor-Phillips. Newborn screening for long-chain 3-hydroxyacyl-coa dehydrogenase and mitochondrial trifunctional protein deficiencies using acylcarnitines measurement in dried blood spots—a systematic review of test accuracy. Frontiers in Pediatrics, Mar 2021. URL: https://doi.org/10.3389/fped.2021.606194, doi:10.3389/fped.2021.606194. This article has 15 citations.
(NCT01379625 chunk 1): Melanie B Gillingham. Study of Triheptanoin for Treatment of Long-Chain Fatty Acid Oxidation Disorder. Oregon Health and Science University. 2011. ClinicalTrials.gov Identifier: NCT01379625
(porta2024triheptanoininpatients pages 1-2): Francesco Porta, Arianna Maiorana, Vincenza Gragnaniello, Elena Procopio, Serena Gasperini, Roberta Taurisano, Marco Spada, Carlo Dionisi-Vici, and Alberto Burlina. Triheptanoin in patients with long-chain fatty acid oxidation disorders: clinical experience in italy. Italian Journal of Pediatrics, Oct 2024. URL: https://doi.org/10.1186/s13052-024-01782-y, doi:10.1186/s13052-024-01782-y. This article has 11 citations and is from a peer-reviewed journal.
(NCT01886378 chunk 1): A Study of UX007 (Triheptanoin) in Participants With Long-Chain Fatty Acid Oxidation Disorders (LC-FAOD). Ultragenyx Pharmaceutical Inc. 2014. ClinicalTrials.gov Identifier: NCT01886378
(NCT05933200 chunk 1): A Study to Determine the Effect of Triheptanoin Compared With Even-Chain MCT on MCEs in Pediatric Patients With LC-FAOD. Ultragenyx Pharmaceutical Inc. 2023. ClinicalTrials.gov Identifier: NCT05933200
(NCT02214160 chunk 1): Long-Chain Fatty Acid Oxidation Disorders (LC-FAOD) Extension Study for Subjects Previously Enrolled in Triheptanoin Studies. Ultragenyx Pharmaceutical Inc. 2014. ClinicalTrials.gov Identifier: NCT02214160
(devine2024ipscderivedlchaddretinal pages 11-12): Tiffany DeVine, Gabriela Elizondo, Garen Gaston, Shannon J. Babcock, Dietrich Matern, Mikhail S. Shchepinov, Mark E. Pennesi, Cary O. Harding, and Melanie B. Gillingham. Ipsc-derived lchadd retinal pigment epithelial cells are susceptible to lipid peroxidation and rescued by transfection of a wildtype aav-hadha vector. Investigative Ophthalmology & Visual Science, 65:22, Sep 2024. URL: https://doi.org/10.1167/iovs.65.11.22, doi:10.1167/iovs.65.11.22. This article has 3 citations and is from a domain leading peer-reviewed journal.
(kochan2025howgenesmeet pages 7-9): Zdzislaw Kochan and Joanna Karbowska. How genes meet diet in lchad deficiency: nutrigenomics of fatty acid oxidation disorder. International Journal of Molecular Sciences, 26:10140, Oct 2025. URL: https://doi.org/10.3390/ijms262010140, doi:10.3390/ijms262010140. This article has 2 citations.

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Subtypes

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Pathograph

Phenotypes

Genetic Associations

Treatments

Environmental Factors

Biochemical Markers

Source YAML

References & Deep Research

References

Deep Research

Disease Characteristics Research Template

Target Disease

Research Objectives

1. Disease Information

2. Etiology

3. Phenotypes

4. Genetic/Molecular Information

5. Environmental Information

6. Mechanism / Pathophysiology

7. Anatomical Structures Affected

8. Temporal Development

9. Inheritance and Population

10. Diagnostics

11. Outcome/Prognosis

12. Treatment

13. Prevention

14. Other Species / Natural Disease

15. Model Organisms

Citation Requirements

Output Format

Comprehensive Research Report: Mitochondrial Trifunctional Protein Deficiency (MTPD)

Executive summary

1. Disease information

1.1 Definition and current understanding

1.2 Key identifiers (best available from retrieved sources)

1.3 Synonyms / alternative names

1.4 Evidence source type

2. Etiology

2.1 Disease causal factors

2.2 Risk factors

2.3 Protective factors

2.4 Gene–environment interaction (GxE)

3. Phenotypes (clinical spectrum)

3.1 Core phenotype categories (with HPO suggestions)

3.2 Frequency and phenotype statistics from cohorts/series

3.3 Quality of life impacts (supported proxy endpoints)

4. Genetic / molecular information

4.1 Causal genes

4.2 Pathogenic variants and variant classes (examples from retrieved sources)

4.3 Genotype–phenotype correlations (high level)

4.4 Modifier genes / epigenetics / chromosomal abnormalities

5. Environmental information

6. Mechanism / pathophysiology (with ontology suggestions)

6.1 Canonical causal chain (upstream → downstream)

6.2 Recent mechanistic developments (2023–2024 prioritized)

6.3 Biochemical abnormalities (diagnostic / mechanistic)

7. Anatomical structures affected

7.1 Organ/system level (UBERON suggestions)

7.2 Subcellular compartments (GO cellular component suggestions)

8. Temporal development (natural history)

9. Inheritance and population

9.1 Epidemiology (best available from retrieved sources)

9.2 Population genetics / founder effects

10. Diagnostics

10.1 Core diagnostic tests and biomarkers (real‑world implementation)

10.2 NBS test accuracy statistics

10.3 Differential diagnosis

11. Outcomes / prognosis

12. Treatment

12.1 Standard management (current practice)

12.2 Triheptanoin (Dojolvi/UX007) — evidence and implementation

12.3 Clinical trials (applications / real-world pipeline)

12.4 Emerging/experimental therapeutics (2024 translational)

13. Prevention

14. Other species / natural disease