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mimics defect in the electron transport chain
pyruvate dehydrogenase deficiency
congenital anomalies (brain and kidneys), overwhelming lactic acidosis, multisystem failiure, death, x-linked dominent usually
pyruvate dehydrogenase deficiency
converts NADH to NAD+
complex 1
converts FADH2 to FAD
complex 2
pumps protons across the mito inner membrane
1,3,4
make ATP from ADP and Pi
complex 5
complex completely nuclear encoded
complex 2
recurrence risk of mitochondrial inheritance
can reach 100%
threshold
different body systems may need different amount of mutant mito to be affected
tissue with high energy demands
nerves, muscles, endocrine tissues, kidneys
ocular myopathy, pigmentary retinopathy, onset less than 20 years, cardiac conduction defect, ataxia, CSF protein, abn of heart, brain, renal tubules, endocrine glands, single most common cause cause 4.9 kb mito deletion
Kearns-Sayre syndrome
recurrence risk of kearns sayre
4%
mitochondrial myopathy, encephalopathy, lactic acidosis, stroke like episodes, malignant migraine
MELAS
A3243G mutation
MELAS
most common manifestation of A3243G
deafness and diabetes
rapid visual loss in the second or third decade, rapid vision loss in 2nd to 3rd decade, low penetrance, more likely to be males affected, 40% of males will go blind
LHON
G11778A
most common LHON mutation
homoplasmic A3243G mutation
mitochondrial associated hearing loss
homoplastic A1555G mutation
usually causes hearing loss in a multifactorial manner in mito hearing loss
sensorineural deafness, dystonia, dysphagia, cortical blindness and paranoia, cause by X- linked disorder of a mutation in DDP1 involved in mitochondrial improt
Mohr-Tranebjaerg syndrome
caused by a trinucleotide repeat expansion (GAA) leading to insufficient levels of frataxin, a mitochondrial iron chaperone that shields iron from reactive oxygen species
friedtrich ataxia
causes 1/3 of Leigh disease
SURF1
progressive neurodegenerative disorder predominently of the inferior brain structure (basal ganglia, cerebellum, brain stem)
Leigh disease
nuclear encoded complex 2 genes
cause leigh disease and pheochromocytoma  and paraganglioma
T8993G/C
Leigh disease in 90% or more of mutant plasmy, lesser degree NARP
systemic disease with ophthalmoplegia
Kearns-Sayre syndrome
adult onset ophthalmoplegia
PEO
inheritance of PEO
generally AD
mitochondrial neurogastrointestinal encephalomyopathy
MNGIE
autosomal recessive mutation in thymidine phosphorylase
MNGIE
infantile neuromuscular and/or hepatic failure
mtDNA depletion
myoclonic epilpepsy, ragged red fibers
MERFF
A8344G
MERFF
multiple areas, functional disorders, transiet or intermittent, cluster into "episodes", present during viral illness or fasting
mitochondrial disease
2 or more neuro/muscular/renal tubular disease manifestations
think mito
labs for mito
lactate, organic acids when slightly ill, elevated krebs intermediates, dicarbocylic acids, lactate, ketones, specific markers
body fluids to obtain in mitochondrial disorder
lactate, urine organic acids (krebs cycle intermediates, dicarboxylic acids)
ragged red fibers
deficient mtDNA protein synthesis
late onset inheritance most likely....
maternal
early infantile onset usually inherited
AR
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