Prevalence of large-scale mitochondrial DNA deletions in an adult Finnish population.
BACKGROUND
Large-scale mitochondrial DNA (mtDNA) deletions are associated with clinical conditions such as Kearns-Sayre syndrome and chronic progressive external ophthalmoplegia in adults and Pearson syndrome in children. Reported case series have suggested that deletions are not uncommon in the population, but their prevalence has not been documented.


METHODS
The authors ascertained patients with clinical features associated with mtDNA deletions in a defined adult population in northern Finland. Buccal epithelial samples were requested from each patient fulfilling the selection criteria, and full-length mtDNA was amplified using the long PCR method. Deletion breakpoints were identified using sequencing. Patients with deletions were examined clinically.


RESULTS
The authors identified four patients with single large-scale mtDNA deletions. The prevalence of deletions was calculated to be 1.6/100,000 in the adult population in the province of Northern Ostrobothnia (0.0 to 3.2; 95% CI). Analysis of incident cases from a neighboring province revealed two patients with deletions and yielded a similar population frequency.


CONCLUSIONS
The frequency of large-scale mitochondrial DNA deletions is similar among populations, suggesting that there is a constant rate of new deletions.
Remes
A M
AM
Department of Neurology, University of Oulu, Finland.
Majamaa-Voltti
K
K
Kärppä
M
M
Moilanen
J S
JS
Uimonen
S
S
Helander
H
H
Rusanen
H
H
Salmela
P I
PI
Sorri
M
M
Hassinen
I E
IE
Majamaa
K
K
D000328:Adult; D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D005387:Finland / Q000453:epidemiology; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005820:Genetic Testing; D006801:Humans; D007625:Kearns-Sayre Syndrome / Q000453:epidemiology / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D009154:Mutation / Q000235:genetics; D017246:Ophthalmoplegia, Chronic Progressive External / Q000453:epidemiology / Q000235:genetics*; D015995:Prevalence; D017384:Sequence Deletion / Q000235:genetics*; D013577:Syndrome
D004272:DNA, Mitochondrial