The acquisition of an inheritable 50-bp deletion in the human mtDNA control region does not affect the mtDNA copy number in peripheral blood cells.
The mitochondrial DNA (mtDNA) control region is believed to play an important biological role in mtDNA replication. Large deletions in this region are rarely found, but when they do occur they might be expected to interfere with the replication of the molecule, thus leading to a reduction of mtDNA copy number. During a survey for mtDNA sequence variations in 5,559 individuals from the general Chinese population and 2,538 individuals with medical disorders, we identified a 50-bp deletion (m.298_347del50) in the mtDNA control region in a member of a healthy Han Chinese family belonging to haplogroup B4c1b2, as suggested by complete mtDNA genome sequencing. This deletion removes the conserved sequence block II (CSBII; region 299-315) and the replication primer location (region 317-321). However, quantification of the mtDNA copy number in this subject showed a value within a range that was observed in 20 healthy subjects without the deletion. The deletion was detected in the hair samples of the maternal relatives of the subject and exhibited variable heteroplasmy. Our current observation, together with a recent report for a benign 154-bp deletion in the mtDNA control region, suggests that the control of mtDNA replication may be more complex than we had thought.
Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, People's Republic of China.
Rui
R
Bi
A-Mei
AM
Zhang
Wen
W
Zhang
Qing-Peng
QP
Kong
Bei-Ling
BL
Wu
Xiao-Hong
XH
Yang
Dong
D
Wang
Yang
Y
Zou
Ya-Ping
YP
Zhang
Yong-Gang
YG
Yao
D044466:Asian People / Q000235:genetics; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004261:DNA Replication / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D018628:Gene Dosage / Q000235:genetics; D006801:Humans; D010375:Pedigree; D017384:Sequence Deletion / Q000235:genetics*
D017931:DNA Primers; D004272:DNA, Mitochondrial