Kearns Sayre syndrome (KSS) is a multisystem disorder with a confounding variety of clinical manifestations, including ocular myopathy, pigmentary retinopathy, heart block and ataxia. Endocrinopathies are common in KSS, including growth hormone deficiency, hypogonadism, diabetes mellitus and hypoparathyroidism. A variety of deletions of mitochondrial DNA (mtDNA) are found in most cases. We report on a 5-year-old boy with Addison disease in whom further investigation revealed a 4.9 kilobase mtDNA deletion and KSS. Later he developed severe lactic acidosis and expired.
Conclusion: The degree of mutant mtDNA heteroplasmy in various tissues on autopsy did not correlate well with the clinical manifestations, although this may be due at least in part to replacement with other tissue types. Our report is the first of non-autoimmune Addison disease in KSS and patients with KSS should be evaluated for adrenal insufficiency. Early recognition of adrenal insufficiency is crucial to prevent mortality from this cause.