The prevalence of mitochondrial gene mutations in childhood diabetes in Japan.
To investigate the prevalence of mitochondrial DNA mutations among Japanese children with IDDM as well as in those with NIDDM, a total of 155 patients with IDDM and 30 patients with NIDDM who were younger than 15 years of age at onset were studied for the following mtDNA mutations: 1) the A-->G mutation at position 3243 of mitochondrial leucine transfer RNA (3243 mutation); 2) the G-->A mutation at position 3316 of mitochondrial leucine transfer RNA (3316 mutation), and 3) The T-->C mutation at position 3394 of the mitochondrial NADH dehydrogenase subunit (3394 mutation). None of the 155 IDDM patients had the 3243 mutation. Although two of the 155 IDDM patients had homoplasmy of 3316 and five had 3394 mutations, these frequencies were not significant compared with healthy controls. None of the 30 NIDDM patients had the 3243, 3316 or 3394 mutation. The presence of these mutations even in control subjects suggests that the effect of the 3316 or 3394 mutation on mitochondrial function is relatively mild. It seems that 3316 and 3394 mutations contribute to the manifestation of diabetes together with other genetic and/or environmental factors.
Department of Pediatrics, Kitasato University School of Medicine, Sagamihara, Japan.
N
N
Matsuura
S
S
Suzuki
Y
Y
Yokota
K
K
Kazahari
M
M
Kazahari
T
T
Toyota
M
M
Hirai
A
A
Okuno
S
S
Harada
N
N
Fukushima
A
A
Koike
Y
Y
Ito
T
T
Hotsubo
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D006801:Humans; D007564:Japan; D008297:Male; D017354:Point Mutation
D004272:DNA, Mitochondrial