NEW YORK (Reuters Health) - A mutation in mitochondrial tRNA is responsible for a syndrome that includes hypertension, hypercholesterolemia, and hypomagnesemia, new research shows. This finding could have implications for the more common clustering of hypertension and dyslipidemia seen in the general population.
“It’s been known from epidemiologic studies for the last 20 years that hypertension and dyslipidemia cluster with one another more often than expected by chance,” senior author Dr. Richard P. Lifton, from Yale University in New Haven, Connecticut, told Reuters Health. “But the mechanisms explaining that clustering haven’t been clear.”
The researchers’ search for a shared causative factor unknowingly began a few years ago when they were asked to evaluate a patient with unexplained hypomagnesemia.
Although several known recessive traits were suspected as the cause initially, the team abandoned this theory when the patient described numerous nonsibling family members who also had low magnesium levels -- a finding that is not consistent with a recessive trait. “This immediately told us that this was likely to be a new disease,” Dr. Lifton said.
In studying the patient’s family, the researchers found that not only was hypomagnesemia common, so were hypertension and hypercholesterolemia. Ultimately, Dr. Lifton’s group studied 140 members of the patient’s extended family. The findings are published in the October 21st online issue of Sciencexpress.
Thirty-two members had low magnesium levels and, “remarkably, all of them were on the same maternal lineage,” Dr. Lifton said. This pattern of inheritance “is indicative of a mitochondrial cause of the disease because we get all of our mitochondria from our mothers,” he explained.
This led the researchers to sequence the mitochondrial genome, resulting in the identification of a novel mitochondrial tRNA mutation that disrupts the normal function of the tRNA.
“The importance of this one-of-a-kind family is that it tells us for the first time that a defect in mitochondrial function can cause high blood pressure, high cholesterol, and low magnesium,” Dr. Lifton noted. “This raises the question of whether the known loss of mitochondrial function that occurs with aging might be contributing to the clustering of these metabolic disorders in the general population.”
Dr. Lifton added that further studies are now needed to determine the mechanism by which the mitochondrial mutation leads to hypertension and hypercholesterolemia and “to see whether we can establish a more common occurrence of this same causal relationship in the general population.”
Source: Science 2004. [ Google search on this article ]
MeSH Headings:DNA, Mitochondrial: etiologyCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
