Mitochondrial Inheritance Flashcards
Mitochondrial DNA is passed from the _____ to _____.
mother; all of her children
Mitochondrial diseases are disorders caused by _____.
dysfunction of the respiratory chain
What is the mutation in Kearns-Sayre?
a large deletion of mtDNA (~12 genes)
What are the signs and symptoms of MELAS?
muscle weakness, seizures, repetitive stroke-like episodes, elevated lactic acidosis
replicative segregation
multiple copies of mtDNA are randomly sorted among new mitochondria
What is the incidence rate of MERRF? New mutation rate?
1:400,000; very low
What does MELAS stand for?
mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes
What are the signs and symptoms of MERRF?
weakness, myotonia, seizures, ataxia, dementia, ragged-red muscle fibers
What is the incidence rate of Leber Hereditary Optic Neuropathy?
1:30,000
threshold effect
too much mutated mitochondrial DNA in a cell- problems start presenting
What is mutated in MERRF?
MT-TK gene
What is MERRF?
myoclonic epilepsy with ragged-red fibers
What are the clinical manifestations of Kearns-Sayre?
eye problems, cardiac conduction effects, ataxia, deafness, kidney problems
What are 4 mitochondrial diseases?
1) Kearns-Sayre 2) MELAS 3) MERRF 4) Leber Hereditary Optic Neuropathy
Mitochondrial DNA encodes ____ genes.
37
What is the mutated gene in Leber Hereditary Optic Neuropathy?
several mitochondrial genes
What is the MELAS mutation?
several different genes with same manifestation; usually MT-TL1
What is the incidence rate of Kearns-Sayre?
1:100,000
What is the incidence rate of MELAS? What is the new mutation rate?
1:300,000; very low
ataxia
abnormal gait
heteroplasmy
receiving both some mutated and some normal mitochondria
What are the signs and symptoms of Leber Hereditary Optic Neuropathy?
vision loss
Why does Leber Hereditary Optic Neuropathy show reduced penetrance?
50% of males get vision loss, but only 15% of females do
