Kearns-Sayre syndrome (KSS) belongs to the group of neuromuscular disorders known as mitochondrial encephalomyopathies. It has characteristic syndromal features, which include: chronic progressive external ophthalmoplegia, bilateral atypical pigmentary retinopathy, and cardiac conduction abnormalities. So far, only a single case has been reported where a patient with KSS had a normal retina. Herein, we report this extremely rare variant of KSS, which not only presented later than the normal age of presentation, but also had minimal pigmentary retinopathy.
Mitochondrial DNA (mtDNA) deletions are a major cause of chronic progressive external ophthalmoplegia (CPEO) and Kearns-Sayre syndrome (KSS). We analyzed single mtDNA deletions in 11 CPEO and one KSS patients by means of Southern blot and long polymerase chain reaction (PCR) assays. The deletion sizes ranged from 3.4 kb to 6.9 kb whereas the heteroplasmy level varied from 18.8% to 85.5%. Two unique deletions sized 4320 bp and 4717 bp were found. This study represents the first genetic screen of mtDNA disorders in Malaysia, and it follows the data seen in other published reports on CPEO and KSS genetic aetiology.
The authors describe the case of a 50-year-old man with chronic progressive external ophthalmoplegia (CPEO), diabetes mellitus (DM), and coronary artery disease. The patient had no cardiac conduction abnormalities. During coronary artery bypass surgery, his heart and two skeletal muscles were biopsied. All three muscles showed ragged red fibers. The heart muscle showed significant glycogen accumulation. Analysis of mitochondrial DNA (mtDNA) showed a 5019-base-pair deletion, with no duplications. There were morphologically abnormal mitochondria in all 3 muscles, with clinically apparent difference in preservation of function. The combination of diabetes mellitus and mtDNA deletion is fortuitous, as they can be causally linked. The cardiac pathology allows speculation about the possible adaptive processes that may occur in the heart in DM. There are few reported cases with CPEO and excess glycogen in the heart. Most show deposition of fat and poorer clinical outcomes as compared to those with glycogen deposition. This observation may lend support to the hypothesis that in the myocardium, adaptive responses are mediated via changes in glucose handling, whereas alterations in fat metabolism likely represent maladaptation.
Myopathies, although presenting more commonly in the younger age group, can occur and contribute significantly to disability in the elderly. To describe the spectrum of elderly myopathies, we reviewed 52 elderly patients (> 65 years) from the University of Malaya Medical Centre muscle biopsy databank, constituting 6.8% of 759 adult patients (> 18 years) who underwent muscle biopsy between 1992 and 2012. Commonest were the inflammatory myopathies (41/52, 78.8%), of which 43.9% had dermatomyositis; 23.9% polymyositis; 14.6% sporadic inclusion body myositis; 9.8% undifferentiated myositis and 2.4% overlap myositis. Seven patients (13.4%) had genetic myopathy; 2 muscular dystrophy and 5 chronic progressive external ophthalmoplegia, while 4 patients (7.7%) had drug-associated myopathy, 3 with statins. Malignancies were seen in 9.8% of inflammatory myopathies at diagnosis. Both acquired and genetic myopathies are seen in elderly Malaysians of all ethnicities and should not be misdiagnosed as some are potentially treatable and/or associated with malignancy.