Mitochondrial Myopathies

Question 1

Short statue, seizures, stroke-like episodes with focused neurological deficits, recurrent headaches, cognitive regression, disease progression, ragged-red fibers

Answer 1

MELAS

Mitochondrial Encephalomyopathy Lactic Acidosis and Stroke-like Episodes

Question 2

Mitochondrial Myopathy (muscle weakness),
Encephalopathy (brain and CNS disease),
Lactic Acidosis
Headaches
Stroke-like Episodes (partial paralysis, partial vision loss, or other neurological abnormalities) followed by seizures

Answer 2

MELAS

Question 3

Hallamark: Myoclonus (brief, sudden, twitching/spasms)
Epileptic seizures
Cerebellar Ataxia (impaired coordination)
Ragged-red fibers

Additional symptoms:
hearing loss, lactic acidosis, short stature, exercise intolerance, dementia, cardiac defects, eye abnormalities, and speech impairment

Answer 3

MERRF

Myoclonic Epilepsy and Ragged-Red Fiber Disease

Question 4

Afflicts infants or young children with episodes of encephalopathy and low carnitine in the blood.

Answer 4

MCAD

Medium-Chain Acyl-CoA Dehydrongenase Deficiency

Question 5

Can’t metabolize/convert medium-chain fatty acids to energy during periods without food (fasting) or illness.

Symptoms: vomiting, lethargy, and hypoglycemia.

Answer 5

MCAD

Medium-Chain Acyl-CoA Dehydrongenase Deficiency

Question 6

encephalopathy, balance problems, ataxia, epilepsy, cognitive impairment, psychiatric symptoms, eye movement disorders, involuntary movements, peripheral neuropathy.

Answer 6

MIRAS

Mitochondrial Recessive Ataxia Syndrome

Question 7

Treatment:
IV 10% dextrose during acute decompensation
Avoid fasting states

Answer 7

MCAD

Question 8

Clinical features: Weakness, lethargy

Diagnostics:
↓ Glucose and ↓ ketones
hyperammonemia
↓↓↓ plasma carnitine levels

Treatment: Avoid fasting states

Answer 8

Primary carnitine deficiency

A defect of the carnitine transporter,
which transfers fatty acids across the mito memb

Question 9

Clinical features: Seizures

Diagnostics:
↓ Glucose and ↓ ketones
hyperammonemia
↓ Total and free carnitine 
↑ acylcarnitine
↑ ALT, ↑ AST

Answer 9

Carnitine palmitoyltransferase II deficiency (CPT II)

impaired LONG-chain fatty acid oxidation in the mitochondria

Question 10

Clinical features: Dehydration, poor feeding, Vomiting
Lethargy, Seizures, Cardiopulmonary collapse

Diagnostics:
↓ Glucose and ↓ ketones
Hyperammonemia
Hyperuricemia (Metabolic acidosis)
↑ AST and ALT
↑ PT and aPTT
Genetic testing

Answer 10

Medium-chain acyl-CoA dehydrogenase deficiency (MCAD deficiency)