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Molecular Exam 3 > Mitochondrial Genetics and Disease > Flashcards

Mitochondrial Genetics and Disease Flashcards

1
Q

What is the function of the mitochondria?

A

provide cellular energy in the form of ATP for the cell

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2
Q

What are the two ways the mitochondria can provide energy?

A

Electron transport chain and oxidative phosphorylation

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3
Q

Mitochondria have their own _____

A

DNA

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4
Q

What are the characteristics of mitochondrial disorders?

A

clinical variability and age related progression of disease

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5
Q

What does MERRF stand for?

A

myoclonus epilepsy with ragged red fibers

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6
Q

What does MELAS stand for?

A

mitochondrial encephalopathy lactic acidosis and stroke like episodes

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7
Q

What does KSS stand for?

A

Kearns-sayre syndrome

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8
Q

What does CPEO stand for?

A

chronic progressive external ophthalmoplegia

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9
Q

What does LHON stand for?

A

leber hereditary optic neuropathy

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10
Q

What is a mitochondrial myopathy?

A

muscle disease caused by mitochondrial disfunction

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11
Q

What are clinical characteristics of mitochondrial myopathies?

A

muscle weakness
exercise intolerance
lactic acidosis
neurological signs: mitochondrial encephalopathies
other abnormalities: vomiting, seizures, dementia, stroke like episodes, ptosis, ophthalmoplegia, blindness, cardiomyopathy

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12
Q

What are ragged red fibers?

A

aggregates of abnormal mitochondria that form red sarcolemmal blotches

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13
Q

Are mitochondria maternally or paternally inherited?

A

maternally

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14
Q

What is heteroplasmy?

A

when a mtDNA mutation occurs, a mixture of normal mitochondria and mutant mitochondria occurs in one cell

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15
Q

What is threshold in mitochondrial disease?

A

when there is too many mutant mitochondria, disease will result

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16
Q

In the ETC, enzyme complexes I to IV oxidize what?

A

NADH and FADH2

17
Q

What is complex V?

A

ATP synthase

18
Q

Complexes I through V are encoded by what?

A

nuclear and mitochondrial DNA

19
Q

Does mtDNA have a repair mechanism?

A

no

20
Q

______ mutations in mtDNA tRNA goes lead to MELAS and MERRF

A

point

21
Q

mtDNA ______ deletions and rearrangements lead to KSS and CPEO

A

genome

22
Q

What are the clinical features of MERRF?

A 
myoclonus (involuntary jerking of the muscle)
myoclonic epilepsy
ataxia
ragged red fibers
seizures
23
Q

90% of MERRF caused by what?

A

2 mutations of tRNA Lys

24
Q

85% of MERFF cases due to ___ to ___ mutation in mtDNA tRNA lys one
5% are due to ____ to ____

A

A to G; G to C

25
Q

What are characteristics of MELAS?

A 
seizures
blindness
headaches
anorexia
recurrent vomiting
lactic acidosis 
ragged red fibers
26
Q

When is the age of onset for MELAS?

A

2-10 years

27
Q

What is the typical cause of MELAS?

A

A3243B mutation in tRNA leu

28
Q

What are the characteristics of KSS?

A

onset before age 20
retinitis pigmentosa
at least one of the following: cardiac conduction abnormality, cerebellar ataxia, cerebral spinal protein level above 100 mg/dL

29
Q

What is the main cause of KSS?

A

mtDNA rearrangements including duplicated mtDNA, deleted mtDNA and insertions

30
Q

Where are ragged red fibers seen in KSS?

A

skeletal muscle cells

31
Q

What are the characteristics of CPEO?

A

mild to moderate mitochondrial myopathy, ragged red fibers in skeletal muscle, mtDNA rearrangments
ptosis

32
Q

What are the characteristics of LHON?

A

mitochondrial mutation only affects optic nerve
no muscle involvement
acute or subacute, bilateral, or central vision lost
degeneration of the retinal ganglion cell layer and optic nerve
age of onset= 20s to 30s

33
Q

What is the cause of LHON?

A

mtDNA mutations in coding genes of complex I proteins

34
Q

Mutations affect mtDNA genes encoding complex I proteins are ______ substitutions

A

single base pair

Molecular Exam 3 (13 decks)

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