by Gina Kolata for The New York Times:

African-Americans have a slightly higher risk of Alzheimer’s disease than people of largely European ancestry, but there is no major genetic difference that could account for the slight excess risk, new research shows.

The results are from one of the only large studies ever done on Alzheimer’s in African-Americans. Researchers identified the same gene variants in older African-Americans that they had found in older people of European ancestry. But they found that African-Americans with Alzheimer’s disease were slightly more likely to have one gene, ABCA7, that is thought to confer risk for the disease.

Another gene, APoE4, long known to increase Alzheimer’s risk in older white people, was present in about the same proportion of African-Americans with Alzheimer’s as it is in people of European ancestry.

The researchers’ paper was published online on Tuesday in The Journal of the American Medical Association. In an accompanying editorial, Dr. Robert L. Nussbaum of the University of California, San Francisco, noted that finding ABCA7 and APoE4 in African-Americans as well as those of European ancestry “strengthens the case” that the genes are important in conferring susceptibility to the disease.

by John Gever for MedPage Today:

Four additional genes associated with increased risk of Alzheimer’s disease, as well as a surprising biological pathway that may be involved in the condition, were reported here.

Three of the four new genes have functions that make sense in the context of Alzheimer’s disease but that had not been targets of previous research, while the fourth does not have a known product, according to Valentina Moskvina, PhD, of Cardiff University in Wales.

In a separate study at the university, an analysis of mutations previously associated with Alzheimer’s disease, reported by Peter Holmans, PhD, suggested that a cellular process called endocytosis is affected by many of them. Some earlier studies had linked endocytosis — in which cells take in proteins or other molecules by engulfing them — to beta-amyloid protein trafficking, but it had not been high on the list of processes thought to account for Alzheimer’s disease pathology.

by Alice Park for Time:

Researchers have identified two genes that affect brain size and may be linked not only to IQ, but also to our risk of developing brain disorders like Alzheimer’s disease.

Scientists have known for some time that the size and volume of certain parts of the brain are linked to disorders including developmental conditions such as autism and degenerative diseases like Alzheimer’s. The brains of autistic children, for example, tend to be bigger than those of unaffected youngsters, and in Alzheimer’s patients, the brain region responsible for memory, the hippocampus, tends to be smaller.

But what influences brain size to begin with? It’s a feature that is highly heritable among humans, suggesting that genes may play a role. That suggests in turn that such genes may also influence vulnerability to any number of mental disorders that are linked to brain size, above and beyond the genes that directly affect memory or language skills, for example.

by Kim Carollo for ABC News:

A team of researchers will soon try out an experimental drug that could prevent Alzheimer’s disease in a group of people with a genetic mutation that makes it likely they will develop the debilitating condition.

Scientists will begin a clinical trial of crenezumab in about 300 Colombians whose genes predispose them to a rare form of Alzheimer’s that hits very early — usually in the 40s or 50s — and can affect multiple members of the same family.  Funding for the study is provided by the National Institutes of Health, Genentech and the Banner Alzheimer’s Initiative.  Genentech is the developer of the experimental drug.

There will also be a subjects with the same mutation recruited in the U.S., but those people still need to be identified.

“Clinical trials will be done at a time when a patient has no symptoms.  We’re trying to stop or slow the onset of the disease in this group of patients,” said Richard Scheller, executive vice president of research and development at Genentech.  “We know when they will contract the disease because of the numerous studies that have been done on the mutation.

by Dementia Today

GENETIC RISK FACTORS

by Science Daily

Efforts to understand how the aging process affects the brain and cognition have expanded beyond simply comparing younger and older adults.

“Everybody ages differently. By looking at genetic variations and individual differences in markers of vascular health, we begin to understand that preventable factors may affect our chances for successful aging,” said Wayne State University psychology doctoral student Andrew Bender, lead author of a study supported by the National Institute on Aging of the National Institutes of Health and now in press in the journal Neuropsychologia.

The report, “Age-related Differences in Memory and Executive Functions in Healthy APOE ε4 Carriers: The Contribution of Individual Differences in Prefrontal Volumes and Systolic Blood Pressure,” focuses on carriers of the ε4 variant of the apolipoprotein (APOE) gene, present in roughly 25 percent of the population. Compared to those who possess other forms of the APOE gene, carriers of the ε4 allele are at significantly greater risk for Alzheimer’s, dementia and cardiovascular disease.

by University of California

Two research studies, co-led by UC Davis neurologist Charles DeCarli and conducted by an international team that included more than 80 scientists at 71 institutions in eight countries, has advanced understanding of the genetic components of Alzheimer’s disease and of brain development. Both studies appear in the April 15 edition of the journal Nature Genetics.

The first study, based on a genetic analysis of more than 9,000 people, has found that certain versions of four genes may speed shrinkage of a brain region involved in making new memories. The brain area, known as the hippocampus, normally shrinks with age, but if the process speeds up, it could increase vulnerability to Alzheimer’s disease, the research suggests.

The second paper identifies two genes associated with intracranial volume — the space within the skull occupied by the brain when the brain is fully developed in a person’s lifespan, usually around age 20.

by Gates Cambridge Scholarships

Researchers have discovered the existence of a shared pathway through which multiple genes and their byproducts affect people’s risk of developing Alzheimer’s Disease.

The research could be an important focus for future gene discovery and the development of targeted therapies to fight against Alzheimer’s. It has been published in the latest edition of The American Journal of Human Genetics.

The study, led by Gates Cambridge alumnus Towfique Raj [2005] from the University of Cambridge’s Department of Neurology, Harvard Medical School and the Broad Institute of MIT and Harvard, explored large-scale human genome data to better understand the functions and interactions of specific locations of genes on a chromosome associated with Alzheimer’s Disease.

by Science Daily

A new gene that causes early-onset of Alzheimer’s disease has been discovered by the research team of Dominique Campion at the Insert unit 1079 “Genetics of cancer and neuropsychiatric diseases” in Rouen. The research scientists showed that in the families of 5 of 14 patients suffering from the disease, mutations were detected on the gene SORL1. This gene regulates the production of a peptide involved in Alzheimer’s disease.

The results of this study have been published in the review Molecular Psychiatry, issued April 3rd.

Precise genetic mutations have been seen to play a part in early-onset forms of Alzheimer’s disease. However, there is a sub-population of patients in whom there is no mutation of these genes. So how can these patients, in whom there are no pre-established mutations, be suffering from early-onset Alzheimer’s?

To explore this question, the research team working under the leadership of Dominique Campion and Didier Hannequin (Inserm unit 1079 and Centre national de référence malades Alzheimer jeunes, University hospital Rouen), studied the genes from 130 families suffering from early-onset forms of Alzheimer’s disease.

by Zee News

Researchers have produced the first atlas of the surface of the human brain based upon genetic information.

The atlas reveals that the cerebral cortex – the sheet of neural tissue enveloping the brain – is roughly divided into genetic divisions that differ from other brain maps based on physiology or function. The genetic atlas provides scientists with a new tool for studying and explaining how the brain works, particularly the involvement of genes.

“Genetics are important to understanding all kinds of biological phenomena,” said William S. Kremen, PhD, professor of psychiatry at the UC San Diego School of Medicine and co-senior author with Anders M. Dale, PhD, professor of radiology, neurosciences, and psychiatry, also at the UC San Diego School of Medicine.

“If we can understand the genetic underpinnings of the brain, we can get a better idea of how it develops and works, information we can then use to ultimately improve treatments for diseases and disorders,” said Chi-Hua Chen, PhD, first author and a postdoctoral fellow in the UC San Diego Department of Psychiatry.