Health Dictionary

Overview

Pyruvate Dehydrogenase Deficiency (PDHA) is a human genetic disease. It follows a sex-linked, dominant inheritance pattern, but is approximately equally prevalent in both males and females. It affects a gene which codes for a critical enzyme complex, the Pyruvate dehydrogenase complex (PDC) which links the metabolic pathways of glycolysis and the citric acid cycle by transforming pyruvate into Acetyl CoA

The pyruvate dehydrogenase complex facilitates oxidative decarboxylation, the chemical reaction between glycolysis and the citric acid cycle.

Presentation

PDHA causes Lactic acidosis; large amounts of lactic acid in the blood but with a normal pyruvate/lactate ratio. Symptoms are varied, and include developmental defects (especially of the brain and nervous system), muscular spasticity and early death.

Differential diagnosis

Pyruvate dehydrogenase deficiency must be differentiated from other diseases that cause neurological manifestations in infants.

Diseases	Type of motor abnormality				Clinical findings	Laboratory findings and diagnostic tests	Radiographic findings
Diseases	Spasticity	Hypotonia	Ataxia	Dystonia	Clinical findings	Laboratory findings and diagnostic tests	Radiographic findings
Leigh syndrome	–	–	+	+	Progressive psychomotor regression Seizures External ophthalmoplegia Lactic acidosis Vomiting	Increased lactate levels in blood and CSF Genetic testing	MRI: abnormal white matter signal in the putamen, basal ganglia, and brainstem on T2 images
Niemann-Pick disease type C	–	–	+	+	Progressive neurodegeneration Hepatosplenomegaly Systemic involvement of liver, spleen, or lung preceedes neurologic symptoms	Abnormal liver function tests Fibroblast cell culture with filipin staining	MRI: Cerebral and cerebellar atrophy Thinning of the corpus callosum
Infantile Refsum disease	–	+	+	–	Abnormalities of the optic nerve and disc Retinitis pigmentosa Sensorineural hearing loss Hepatomegaly and cirrhosis Neurologic deterioration is slower than in Zellweger syndrome or ALD	Elevated plasma VLCFA levels	—
Adrenoleukodystrophy	+	–	–	–	Cognitive and behavioral abnormalities Adrenal insufficiency Hyperpigmented skin Gonadal dysfunction Neurologic deterioration progresses at a variable rate	Elevated plasma VLCFA levels Molecular genetic testing for mutations in the ABCD1 gene	—
Zellweger syndrome	–	+	–	–	Craniofacial dysmorphism Hepatomegaly Neonatal seizures Profound developmental delay MRI findings include cortical and white matter abnormalities Neurologic deterioration is rapid and infants rarely survive beyond six months of age	Elevated plasma VLCFA levels Elevated levels of phytanic acid, pristanic acid, and pipecolic acid in plasma and fibroblasts Reduced plasmalogen in erythrocytes Molecular genetic testing for mutations in the PEX1 or PEX6 genes	—
Pyruvate dehydrogenase deficiency	+	+	+	–	Lactic acidosis Seizures Intellectual disability	Elevated lactate and pyruvate levels in blood and CSF Abnormal PDH enzymatic activity in cultured fibroblasts	—
Arginase deficiency	+	–	–	–	Hyperammonemia Encephalopathy Respiratory alkalosis	Elevated ammonia level Elevated arginine level	—
Holocarboxylase synthetase deficiency	–	+	–	–	Ketoacidosis Dermatitis Alopecia Seizures Developmental delay	Elevated levels of: Beta-hydroxyisovalerate Beta-methylcrotonylglycine Beta-hydroxypropionate Methylcitrate Tiglylglycine	—
Glutaric aciduria type 1	–	–	–	+	Episodes of metabolic decompensation and encephalopathy often precipitated by infection and fever Rarely presents in the newborn period Microencephalic macrocephaly Seizures (approximately 20 percent) Cognitive function is preserved	Elevated levels of: glutaric acid 3-hydroxyglutaric acid	MRI: Frontal and temporal atrophy
Ataxia telangiectasia	–	–	+	–	Progressive cerebellar ataxia Abnormal eye movements Oculocutaneous telangiectasias Immune deficiency Increased risk of malignancy	Elevated serum alpha-fetoprotein level Low IgA and IgG levels Lymphopenia Genetic testing for mutation in the ATM gene	—
Pontocerebellar hypoplasias	–	+	–	–	Progressive muscle atrophy Microcephaly Developmental delay	Genetic testing for PCH gene mutations	MRI : Small cerebellum and brainstem including the pons
Metachromatic leukodystrophy	–	+	+	–	Regression of motor skills Seizures Optic atrophy Reduced or absent deep tendon reflexes Intellectual disability	Deficient arylsulfatase A enzyme activity in leukocytes or cultured skin fibroblasts	—
Pelizaeus-Merzbacher	+	–	+	–	Nystagmus Cognitive impairment Onset in infancy Slowly progressive Language development may be normal	Genetic testing for mutations in PLP1 gene	MRI: White matter abnormalities
Angelman syndrome	–	–	+	–	Profound intellectual disability Postnatal microcephaly Typical abnormal behaviors (paroxysmal laughter, easily excitable)	Methylation studies and chromosome microarray to detect chromosome 15 anomalies and UBE3A mutations	—
Rett syndrome	+	–	–	+	Occurs almost exclusively in females Normal development during first six months followed by regression and loss of milestones Loss of speech capability Stereotypic hand movements Seizures Autistic features	Clinical diagnosis Genetic testing for MECP2 mutations	—
Lesch-Nyhan syndrome	+	–	–	+	Self-mutilating behavior Urinary stones due to hyperuricemia	Elevated uric acid level Abnormal enzymatic activity of HPRT in cultured fibroblasts Genetic testing for HPRT gene mutations	—
Miller-Dieker lissencephaly	+	+	–	–	Lissencephaly Microcephaly Dysmorphic features Seizures Failure to thrive	Cytogenetic testing for 17p13.3 microdeletion	—
Dopa-responsive dystonia	+	–	–	+	Onset in early childhood Symptoms worsen with fatigue and exercise	Positive response to a trial of levodopa	—

Genetics

PDHA is most commonly linked to the alpha unit of E1, but recessive variants exist.

Treatment

Use of a ketogenic diet has been described.^[1]

Current research is being conducted on the viability of Dichloroacetic acid to treat the lactic acidosis commonly accompanied by this disorder.^[2]^[3] Additionally, there is research being conducted on the viability of gene therapy for sufferers of this condition as well as many other mitochondrial defects.

References

↑ Barañano KW, Hartman AL (2008). “The ketogenic diet: uses in epilepsy and other neurologic illnesses” (). Curr Treat Options Neurol. 10 (6): 410–9. doi:10.1007/s11940-008-0043-8. PMC 2898565. PMID 18990309. Unknown parameter |month= ignored (help)
↑ Berendzen K, Theriaque DW, Shuster J, Stacpoole PW (2006). “Therapeutic potential of dichloroacetate for pyruvate dehydrogenase complex deficiency”. Mitochondrion. 6 (3): 126–35. doi:10.1016/j.mito.2006.04.001. PMID 16725381. Unknown parameter |month= ignored (help)
↑ Stacpoole PW, Kurtz TL, Han Z, Langaee T (2008). “Role of dichloroacetate in the treatment of genetic mitochondrial diseases”. Adv. Drug Deliv. Rev. 60 (13–14): 1478–87. doi:10.1016/j.addr.2008.02.014. PMID 18647626.

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Template:WikiDoc Sources

[pmid18990309-1] Barañano KW, Hartman AL (2008). “The ketogenic diet: uses in epilepsy and other neurologic illnesses” (). Curr Treat Options Neurol. 10 (6): 410–9. doi:10.1007/s11940-008-0043-8. PMC 2898565. PMID 18990309. Unknown parameter |month= ignored (help)

[pmid16725381-2] Berendzen K, Theriaque DW, Shuster J, Stacpoole PW (2006). “Therapeutic potential of dichloroacetate for pyruvate dehydrogenase complex deficiency”. Mitochondrion. 6 (3): 126–35. doi:10.1016/j.mito.2006.04.001. PMID 16725381. Unknown parameter |month= ignored (help)

[pmid18647626-3] Stacpoole PW, Kurtz TL, Han Z, Langaee T (2008). “Role of dichloroacetate in the treatment of genetic mitochondrial diseases”. Adv. Drug Deliv. Rev. 60 (13–14): 1478–87. doi:10.1016/j.addr.2008.02.014. PMID 18647626.

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