Kearns Sayre Syndrome--case report with review of literature.

Kearns-Sayre Syndrome is form of rare mitochondrial cytopathy, first described by Thomas P. Kearns and George Pomeroy Sayre in 1958 and is characterized by progressive external opthalmoplegia, cardiac conduction block, pigmentary retinal degeneration, variable number of red ragged fibers on muscle biopsy. It presents before the child reaches the age of twenty. Kearns-Sayre syndrome may affect many organ systems and additional features may include myopathy, dystonia, bulbar symptoms in the form of dysarthria and nasal regurgitation and bilateral facial weakness. Endocrine abnormalities (e.g., diabetes, growth retardation/short stature, and hypoparathyroidism), bilateral sensorineural deafness, dementia, cataracts, and proximal renal tubular acidosis, skeletal muscle weakness (proximal more than distal) and exercise intolerance are additional features. Kearns Sayre Syndrome occurs as a result of large-scale single deletions (or rearrangements) of mitochondrial DNA (mtDNA), which is usually not inherited but occurs spontaneously, probably at the germ-cell level or very early in embryonic development. No disease-modifying therapy is available for Kearns-Sayre syndrome (KSS). Management is supportive vigilance for detection of associated problems. In the future, potential treatment in patients with Kearns-Sayre syndrome may attempt to inhibit mutant mtDNA replication or encourage replication of wild-type mtDNA.

Facial anomalies in a patient with cytochrome-oxidase deficiency and subsequent Kearns-Sayre syndrome with growth hormone deficiency.

The authors report on a patient with mild cranio-facial abnormalities observed at birth and growth hormone deficiency, which later developed a typical Kearns-Sayre syndrome. Facial abnormalities are similar to those reported in the fetal alcohol syndrome (a typical neural crest syndrome). In the authors' opinion, they could be an abnormality of neural crest cell development or migration, due to expression of antenatal oxidative phosphorylation deficiency in neural crest cells or to an interference of defective oxidative phosphorylation with neural crest cells signal(s). On this ground, the Kearns-Sayre syndrome can be considered a neurocristopathy and the studies on this syndrome should take into account those diseases commonly associated with neurocristopathies (i.e. facial, endocrine, osseous, cardiovascular and of peripheral nerve system).

Kearns Sayre syndrome: an unusual form of mitochondrial diabetes.

Kearns Sayre syndrome (KSS) is a mitochondrial disorder characterized by the emergence before age 20 of progressive external ophthalmoplegia, pigmentary retinopathy, together with other heterogeneous clinical manifestations, including cardiac conduction defects, muscle abnormalities and endocrinopathies. KSS is associated with large heteroplasmic deletions in mitochondrial DNA. We report the case of a 43-year-old woman, with diabetes mellitus as a first manifestation at age 19. Later, she exhibited bilateral ptosis and external ophthalmoplegia with progressive worsening. DNA analysis identified a large mitochondrial DNA (mtDNA) deletion, which confirmed the diagnosis of KSS. By reporting this case with diabetes mellitus as first manifestation, we aim at emphasizing problems of diagnosis in these subtypes of mitochondrial diabetes.

Cerebral folate deficiency and leukoencephalopathy caused by a mitochondrial DNA deletion.

OBJECTIVE: Our aim was to describe a child with an incomplete form of Kearns-Sayre syndrome who presented profound cerebrospinal fluid (CSF) folate deficiency and his response to folinic acid supplementation METHODS: CSF 5-methyltetrahydrofolate was analyzed by HPLC with fluorescence detection and mitochondrial DNA deletions by southern blot hybridization. RESULTS: Cranial magnetic resonance imaging showed a leukoencephalopathy. Profound CSF 5-methyltetrahydrofolate deficiency was observed with normal blood folate values and decreased CSF/serum folate ratio, suggesting a transport defect across the blood-brain barrier. Folinic acid treatment was established, and after 1 year clinical response to folinic supplementation was remarkable, with almost normal white matter image. INTERPRETATION: The clinical response after folinic therapy highlights the need for the study of cerebral folate deficiency in patients with mitochondrial disorders and white matter lesions.

Early retinal involvement in mitochondrial myopathy with mitochondrial DNA deletion.

BACKGROUND: Mitochondrial DNA (mtDNA) deletions have been reported in types of mitochondrial myopathy, including Kearns-Sayre syndrome (KSS). We examined mtDNA, skeletal muscle findings, and retinal electrophysiologic function in a patient believed to have incomplete KSS with ptosis and characteristic (so called salt and pepper) retinopathy, but without limitation of ocular motility and without other involvement of the central or peripheral nervous system. METHODS: Muscle biopsy specimens were examined by Gomori trichrome stain and electron microscopy. DNA extracted from muscle was examined by Southern blot analysis. Deleted mtDNA was sequenced by direct sequencing with polymerase chain reaction (PCR). Electroretinograms (ERG) and electrooculograms (EOG) were performed for electrophysiologic examination of the retina. RESULTS: There were no ragged red fibers in skeletal muscle specimens, although abnormal aggregation of mitochondria was observed on electron microscopic examination. An mtDNA deletion was detected. It spanned 5266-bp between the tRNASer gene and the ND5 gene. Electroretinographic and electrooculographic findings were normal, although extensive involvement of retinal pigment epithelium was observed on ophthalmoscopic examination. CONCLUSION: Detecting mtDNA deletion is more critical in diagnosing an incomplete phenotype of mitochondrial myopathy than is morphologic examination. We found that ophthalmoscopic fundus abnormalities preceded abnormalities on ERG and EOG.

Kearns-Sayre syndrome in twins: lethal dominant mutation or acquired disease?

We studied twin brothers who met all diagnostic criteria for the Kearns-Sayre syndrome (KSS). The twins reinforce the view that KSS is a specific syndrome. They raise the possibility that the condition is inherited as a lethal dominant trait, a mode of inheritance that explains the observed paucity of familial cases. However, these cases do not exclude the possibility of an acquired cause, such as persistent viral infection of the brain.