Abstract
Background: Kearns-Sayre syndrome (KSS) is a rare mitochondrial DNA deletion disorder presenting before the age of 20 years, characterized by progressive external ophthalmoplegia, pigmentary retinopathy, and systemic manifestations including cardiac, endocrine, and neurological features. Early recognition remains challenging due to its heterogeneous and evolving phenotype.
Case Presentation: We describe a unique case of an 11-year-old male presenting with progressive ophthalmoplegia, bilateral ptosis, pigmentary retinopathy, sensorineural hearing loss, ataxia, and episodic hypersomnolence. His initial clinical course was marked by aplastic anemia with serious anemia and metabolic acidosis at the age of 9 months, after parvovirus infection. He was initially suspected of having sideroblastic anemia but improved with supportive transfusion. In the following years, he had worsening neurosensory impairment, motor clumsiness, and varying alertness. MRI demonstrated bilateral basal ganglia and brainstem changes. Genetic analysis showed a 7.7 kb mitochondrial DNA deletion covering several respiratory complex genes, in line with the diagnosis of Kearns-Sayre syndrome. Treatment with mitochondrial supplements and folinic acid was commenced on the basis of suspected secondary cerebral folate deficiency. The clinical presentation of the patient has been complicated by cyclical hypersomnolence, hypotonia, and progressive neuromuscular deterioration, for which evaluation was warranted through multidisciplinary assessment involving neurology, ophthalmology, audiology, cardiology, and genetics.
Conclusion: This report documents the extensive phenotypic variability of and diagnostic challenge in Kearns-Sayre syndrome, especially when preceded by hematologic presentation. Awareness of multisystem involvement and early time-of-day molecular diagnosis is necessary for effective management and genetic counseling. Folinic acid may provide symptomatic benefit in patients with suspected cerebral folate deficiency, although objective biomarkers were not available in this case.
Keywords
Kearns-Sayre syndrome, Chronic progressive external ophthalmoplegia, Pigmentary retinopathy, Sensorineural hearing loss, Cyclical hypersomnolence