An overview of a cohort of South African patients with mitochondrial disorders.
Mitochondrial disorders are frequently encountered inherited diseases characterized by unexplained multisystem involvement with a chronic, intermittent, or progressive nature. The objective of this paper is to describe the profile of patients with mitochondrial disorders in South Africa. Patients with possible mitochondrial disorders were accessed over 10 years. Analyses for respiratory chain and pyruvate dehydrogenase complex enzymes were performed on muscle. A diagnosis of a mitochondrial disorder was accepted only if an enzyme activity was deficient. Sixty-three patients were diagnosed with a mitochondrial disorder, including 40 African, 20 Caucasian, one mixed ancestry, and two Indian patients. The most important findings were the difference between African patients and other ethnicities: respiratory chain enzyme complexes CI+III or CII+III deficiencies were found in 52.5% of African patients, being of statistical significance (p value = 0.0061). They also presented predominantly with myopathy (p value = 0.0018); the male:female ratio was 1:1.2. Twenty-five (62.5%) African patients presented with varying degrees of a myopathy accompanied by a myopathic face, high palate, and scoliosis. Fourteen of these 25 also had ptosis and/or progressive external ophthalmoplegia. No patients of other ethnicities presented with this specific myopathic phenotype. Caucasian patients (16/20) presented predominantly with central nervous system involvement. Of the South African pediatric neurology patients, Africans are more likely to present with myopathy and CII+III deficiency, and Caucasian patients are more likely to present with encephalopathy or encephalomyopathy.
Department of Paediatrics and Child Health, Steve Biko Academic Hospital, University of Pretoria, PO Box 32781, Totiusdal, Pretoria 0134, South Africa. izelle.smuts@up.ac.za
Izelle
I
Smuts
Roan
R
Louw
Hanli
H
du Toit
Brenda
B
Klopper
Lodewyk J
LJ
Mienie
Francois H
FH
van der Westhuizen
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D044383:Black People / Q000235:genetics; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D045222:Electron Transport Chain Complex Proteins / Q000172:deficiency / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D028361:Mitochondrial Diseases / Q000175:diagnosis / Q000201:enzymology / Q000208:ethnology*; D017237:Mitochondrial Encephalomyopathies / Q000201:enzymology / Q000208:ethnology / Q000235:genetics; D017240:Mitochondrial Myopathies / Q000201:enzymology / Q000208:ethnology / Q000235:genetics; D018482:Muscle, Skeletal / Q000201:enzymology; D010641:Phenotype; D011379:Prognosis; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics / Q000378:metabolism; D015325:Pyruvate Dehydrogenase Complex Deficiency Disease / Q000201:enzymology / Q000208:ethnology / Q000235:genetics; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D044465:White People / Q000235:genetics; D055815:Young Adult
D015415:Biomarkers; D045222:Electron Transport Chain Complex Proteins; D011768:Pyruvate Dehydrogenase Complex