Kearns-Sayre Syndrome (Treatment (Prognosis depends on the number of…
Prognosis depends on the number of organs affected and the proportion of abnormal mtDNA in each organ
Treatment is supportive, not curative.
Surgery for ophthalmic manifestations
Permanent pacemaker for heart conduction defects
Hearing aids, cochlear implants, etc. for hearing loss
Physical and occupational therapy for muscle weakness and ataxia
Hormone replacement therapy for hormone disorders
“Mitochondria cocktail” of riboflavin, coenzyme Q, and carnitine improves energy levels in some patients.
Deletion of large portions of mtDNA.
Loss of genes involved in oxidative phosphorylation pathway.
Most common deletion removes 4,997 nucleotides, which includes 12 mitochondrial genes
Cause of deletion is unknown
Most commonly occurs as a mtDNA mutation, not as an inherited disorder.
When inherited, it comes from the mother because only mothers pass on mtDNA to offspring.
Multi-System Alteration in Function
Eyes have many mitochondria so they are the first to be affected.
All cells of the body have mitochondria. All cells of the body are dependent on mitochondria for ATP
Unknown how the deletions lead to the specific signs and symptoms present, but they are likely due to a lack of cellular energy
The muscular wall of the heart is a high-energy demand tissues, so miitochondria dysfunction leads to cardiovascular disease. Cardiac problems are very common in patients with KSS.
High degree of clinical heterogeneity because a single human cell can contain mutated and wild-type mtDNA. Disease severity depends on the proportion of abnormal DNA to normal DNA
Mitochondria have their own DNA (mtDNA).
mtDNA is used to make proteins in the oxidative phosphorylation pathway (electron transport chain).
A mitochondria is an organelle found in every cell of the human body.
ETC is used to make energy (ATP) for the cell
1.Age of onset before 20.
2.Progressive External Ophthalmoplegia (PEO, weakness of the eye muscles) leading to ptosis (drooping eyelids).
3.Pigmentary Retinopathy (degeneration of the retina).
4.At least one of the following signs or symptoms: cardiac conduction defects, cerebellar ataxia (unsteadiness when walking) and abnormally high levels of protein in the CSF.
Confirmation of diagnosis with muscle biopsy and genetic testing.
Other Common Manifestations
Muscle weakness, deafness, kidney problems, dementia, diabetes mellitus, intestinal disorder, other endocrine disorders, dysarthria, bilateral facial weakness, intellectual deficit, etc.
Early death (debated between studies)