Kearns-Sayre syndrome (KSS) is characterized by the onset of ophthalmoparesis and pigmentary retinopathy before age 20 years. Other frequently associated clinical features include cerebellar ataxia, cardiac conduction block, raised cerebrospinal fluid (CSF) protein content, and proximal myopathy. Affected children have short stature and often have multiple endocrinopathies including diabetes mellitus, hypoparathyroidism, and Addison disease. Renal tubular acidosis (proximal or distal) has been described in numerous cases, with occasional progression to end-stage renal failure. Bilateral sensorineural hearing loss is almost universal in those who survive into the fourth decade of life; this may not be fully corrected with hearing aids.
In a retrospective study by Khambatta et al of 35 patients with Kearns-Sayre syndrome, cardiovascular features of the group included syncope (6 patients; 17%) and sudden cardiac death (4 patients; 11%). The investigators suggested therefore that formal electrophysiologic studies and prophylactic defibrillators be considered in patients with the syndrome. Other cardiovascular features included heart block (11 patients; 31%) and conduction delays (23 patients; 66%).[1]