AMD causes light-sensitive cells in the retina to break down, resulting in progressive loss of central vision. Of the two forms of AMD, the "dry" is more common than the "wet" form. Wet macular degeneration can rapidly lead to blindness, while the dry AMD progresses more slowly.
Last year, Josephine Hoh, associate professor in the Departments of Epidemiology & Public Health and Ophthalmology at Yale and senior author on one of the two new studies, identified a gene for dry AMD and found that both wet and dry AMD are associated with a variant in the complement factor H (CFH) gene on chromosome 1.
Hoh now reports they have found a single nucleotide polymorphism (SNP)—a one-base change in the sequence—of the regulatory part of the HTRA1 gene on chromosome 10 that leads to greatly increased risk of developing the wet form of AMD.
According to Hoh, buildup of abnormal blood vessels in Caucasian patients is compounded by development of large waste deposits called drusen. Chinese patients, she said, develop little to no drusen and progress directly to wet AMD. This study demonstrates that these two major genes, CFH and HTRA1, in two different biological pathways, each affect the risk for a distinct component of the AMD phenotype: CFH influences the drusen of dry AMD, whereas HTRA1 influences blood vessel development, the hallmark of the wet disease type. When the two processes are combined, it leads to the composite characteristics that are seen in some cases of AMD.
Hoh, her collaborators in Hong Kong, and her colleagues at Yale including Michael Snyder and Colin Barnstable in the Departments of Molecular, Cellular and Developmental Biology and Molecular Biophysics and Biochemistry, and Ophthalmology, did trans-racial gene mapping by comparing genomes between precisely defined populations to find the incidence of SNP in a Chinese population—96 with AMD and 130 with normal vision.
"We found that patients with the HTRA1 SNP were 10 times more likely to have wet AMD than those without this gene variant," said Hoh. "While this is only preliminary work, it points to possible directions for future treatment of wet AMD."
Hoh also worked on a replication study led by Kang Zhang at the University of Utah School of Medicine that found a link between the same SNP and AMD. Zhang and his team studied 581 Caucasian patients with AMD and 309 with normal vision. These patients had wet AMD as well as a large amount of drusen.
To confirm the association, the Utah team also examined several donor eyes and measured the expression of the gene and the encoded protein. They found that the expressions were elevated in the eyes of patients who carry HTRA1.
"The marker we have identified is very much associated with AMD, but no one has ever pinpointed the clinical features of the gene. We need to conduct further analysis in order to understand the biological mechanisms," said Hoh.
Karen N. Peart | EurekAlert!
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy