Respiratory chain complexes defects: Complex IV . Kearns-Sayre syndrome
Incidence
Mildly common. Sporadic appearence (non-familial). Deletion of mitochondrial genome in 80%. No cases reported in Saudi Arabia. Affects both boys and girls.
Clinical Characteristics
Ptosis and progressive external ophtalmoplegia (PEO) are the first manifestations of the disease. Pigmentary degeneration of the retina and ataxia are also cardinal symptoms of the disease. Hearing impairment, progressive mental deterioration. Intermittent episodes of stupor and coma. Seizures are rare. Extinguished ERG, abnormal VEP. 80% abn EEG, 80% high CSF protein >100mg%. Spongy deneration of the brain. Muscle biopsy= ragged red fibres. Growth retardation in > 60% of cases (short stature). Lactic and pyruvate acidosis present, mild.
Precipitants
none
Provocation Tests
none
Diagnostic Procedures
Kearns-Sayre syndrome: DB-muscle