A type of mitochondrial myopathy characterized by chronic progressive external ophthalmoplegia with associated cardiac conduction defects, short stature, and hearing loss, and with a typical onset before 20 years of age
Kearns-Sayre syndrome is a type of mitochondrial myopathy. A mitochondrial myopathy is a type of myopathy associated with mitochondrial dysfunction. One of the major distinctions of this condition is the inability of the muscle to perform properly. In mitochondrial myopathies, the underlying cause is a dysfunctional mitochondrion due to a pathological mutation in the mitochondrial DNA.
Kearns-Sayre syndrome typically manifests before the age of 20. It is characterized by chronic progressive external ophthalmoplegia, i.e. a type of eye disorder wherein there is a slowly progressive inability to move the eyes and eyebrows. Other common symptoms include pigmentary retinopathy, conduction block in the heart, cerebellar ataxia, proximal muscle weakness, deafness, hypothyroidism, etc..
The condition is inherited in an autosomal recessive pattern. This means that the individual has two copies of the defective gene and therefore manifests symptoms associated with the disease. A carrier of the disease would have only one copy of the defective gene and therefore may not show symptoms.
Kearns-Sayre syndrome is named after the two patients, Thomas P. Kearns (1922-2011) and George Pomeroy Sayre (1911-1992), who manifested this syndrome. Their case was the first to be reported in 1958.