Mitochondrial

Question 1

[Gen/Mito/Basic]

How many mitochondrial genes?

Answer 1

37

Question 2

[Gen/Mito/Basic]

How many copies of mtDNA in each mitochondria?

Answer 2

2-10

Question 3

[Gen/Mito/Basic]

Three classic phenotypes of mtDNA deletion syndromes? (3)

Answer 3

Kearns-Sayre syndrome
Pearson syndrome
Progressive external ophthalmoplegia (PEO)

Question 4

[Gen/Mito/Basic]

Examples of mitochondrial disorders? (5)

Answer 4

1. MERRF Myoclonic epilepsy and ragged-red fibers
2. MELAS Mitochondrial encephalopathy lactic acidosis and stroke like episodes
3. Leigh syndrome
4. Kearns-Sayre syndrome
5. Pearson syndrome

Question 5

[Gen/Mito/MERRF]

MERRF stands for?

Answer 5

Myoclonic epilepsy and ragged-red fibers

Question 6

[Gen/Mito/MELAS]

MELAS stands for?

Answer 6

Mitochondrial
encephalopathy,
lactic acidosis, and
stroke-like episodes

Question 7

[Gen/Mito/MERRF]

Symptoms of MERRF (Myoclonic epilepsy and ragged-red fibers)? (4)

Answer 7

1. Progressive myoclonic epilepsy
2. Myopathy
3. Hearing loss
4. Dementia

Question 8

[Gen/Mito/MELAS]

Symptoms of MELAS (Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes)? (4)

Answer 8

1. Recurrent episodes of encephalopathy
2. Myopathy
3. Stroke of the young; present with migraine like Headache, Focal neurological deficits
4. Diabetes mellitus of the young

Question 9

[Gen/Mito/Leigh]

Symptoms of Leigh syndrome (Subacute necrotizing encephalopathy) (3)

Answer 9

1. Eye: Optic atrophy, retinitis pigmentosa
2. Basal ganglia defects - difficulty stopping, starting movement, Hypotonia
3. Biochemical: Lactic acidosis, hypoglycemia, 3-methylglutaconyl acidemia (in subtype MEGDEL)

Question 10

[Gen/Mito/KSS]

Symptoms of Kearns-Sayre syndrome? (4)
- Onset
- 3 system

Answer 10

1. Onset before 20 years old
2. Progressive external ophthalmoplegia (PEO), Retinitis pigmentosa, ptosis
3. Cardiac conduction defects
4. Myopathy (ragged red fiber)

Question 11

[Gen/Mito/Pearson]

Symptoms of Pearson syndrome? (4)
- 3 organ systems
- progress

Answer 11

1. Pancreatic dysfunction
2. Myopathy
3. Sideroblastic anemia, Neutropenia
4. Evolution to Kearns-Sayre syndrome
   (Pearson, pancreatitis, pancytopenia, 3Ps)

Question 12

[Gen/Mito/PEO]

Clinical symptoms of Progressive external ophthalmoplegia (PEO)? (3)

Answer 12

Ptosis, impaired eye movements (ophthalmoplegia)
Oropharyngeal weakness
Variable proximal limb weakness with exercise intolerance