A specific genetic defect in one Chinese family shows that high blood pressure was inherited from the female parent, researchers report in Circulation Research: Journal of the American Heart Association.
The defect results from a point mutation -- the substitution of a single DNA "base" for another during replication -- in the genes of a tiny cellular organ called the mitochondria, which generates a cell's energy. When reproductive cells come together to form an embryo, the mitochondrial DNA from the mother cell is passed on to the offspring. Evidence has suggested a mother-child inheritance link for high blood pressure due to mitochondrial inheritance.
The Chinese-led group, which also included researchers from the Cincinnati Children's Hospital Medical Center and the Medical University of Vienna in Austria, provides clinical, genetic, molecular and biochemical evidence that a mitochondrial mutation designated tRNAIle 4263A>G is associated with inherited high blood pressure. The DNA substitution researchers discovered is an adenine-to-guanine switch at position 4263 on the mitochondrial genome (4263A>G).
Geneticists identified a large family from northern China in which 15 of 27 members who descended from the same female ancestor had blood pressures above 140/90 mmHg even after treatment. Only seven of 81 non-maternal relatives had high blood pressure.
Researchers compared the family members with 342 Chinese residents of the same northern area to confirm a maternal link. Analysis of the mitochondrial genome of the maternal relatives and other tests revealed the site of the hypertension-related mutation and showed that it impairs the mitochondrial respiration chain, which increases levels of a reactive oxygen species (i.e., free radicals).
The findings show that inherited mitochondrial dysfunction is involved in high blood pressure and may provide new insights into maternally transmitted hypertension, researchers said.
- S. Wang, R. Li, A. Fettermann, Z. Li, Y. Qian, Y. Liu, X. Wang, A. Zhou, J. Q. Mo, L. Yang, P. Jiang, A. Taschner, W. Rossmanith, M.-X. Guan. Maternally Inherited Essential Hypertension Is Associated With the Novel 4263A>G Mutation in the Mitochondrial tRNAIle Gene in a Large Han Chinese Family. Circulation Research, 2011; 108 (7): 862 DOI: 10.1161/CIRCRESAHA.110.231811
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