[Identification of an ideal noninvasive method to detect A3243G gene mutation in MELAS syndrome].
OBJECTIVE
To identify a better non-invasive method to detect the carrier of mitochondrial A3243G mutation, a cause of mitochondrial encephalopathy-lactic acidosis-stroke like episode (MELAS) syndrome.


METHODS
DNA was extracted from the peripheral blood, urine, hair follicle, and saliva of 25 MELAS syndrome patients carrying A3243G mutation and their mothers and other maternal relatives, 33 persons in number, and the muscle tissues from 5 patients obtained by biopsy. A3243G mutation was detected by PCR-RFLP method, and the A3243G mutation ratio was identified by measuring the density of each band and calculation with the software AlphaEase 5.0.


RESULTS
A3243G mutations were detected in all tissues of the 25 MELAS patients. The A3243G mutation ratio in urine was 62% +/- 9%, significantly higher than that in the blood [(36% +/- 10%), t = -11.13, P < 0.01]. A3243G mutations were detected in at least one tissue of the 28 maternal relatives. The A3243G mutation rates in their urine samples was 33.0% (5.0% - 70.4%), significantly higher than that in their blood samples [8.0% (0 - 33.3%), z = -4.197, P < 0.01]. There was no significant difference in A3243G mutation ratio among the samples of hair follicle, saliva, and blood.


CONCLUSIONS
The A3243G mutation ratio in urine is significantly higher than those in blood samples of the patients and their maternal relatives. A noninvasive method, A3243G mutation ratio analysis of urine is superior to that in blood.
Ma
Yi-nan
YN
Department of Central Laboratory, Peking University First Hospital, Beijing 100034, China.
Fang
Fang
F
Yang
Yan-ling
YL
Zhang
Ying
Y
Wang
Song-tao
ST
Xu
Yu-feng
YF
Pei
Pei
P
Yuan
Yun
Y
Bu
Ding-fang
DF
Qi
Yu
Y
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D017241:MELAS Syndrome / Q000175:diagnosis* / Q000235:genetics* / Q000652:urine; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
D004272:DNA, Mitochondrial