At Queen Mary University in London, researchers have conducted the largest study of genetic sequencing of human diseases known to date, identifying the genetic basis of six different diseases: autoimmune thyroid disease, celiac disease, Crohn’s disease, psoriasis, multiple sclerosis, and type 1 diabetes. For these diseases, the exact cause is not known, but according to the study, it was believed that the diseases were a complex combination of both genetic and environmental factors. For each disease, there was only a small portion of hereditability is explained by genetic variants.
    In past studies and experiments, genetic variants were only identified as weak-effect. For this study, global scientists used highly throughput sequencing techniques in order to identify new variants, along with rarer and higher risk variants. In a previous experiment that contained twenty-five risk genes, the risk genes were found in a sample of nearly 42,000 individuals, 24,892 of the individuals with autoimmune disease, and 17,019 individuals were controls.
    Within the May 2013 edition of the journal Nature, scientists suggest that the overall genetic risk of these diseases more than likely involves a complex combination of weak-effect variants which are common in the overall human population. David van Heel, Professor of Gastrointestinal Genetics at Barts and Queen Mary University, led the study, saying that there is a lesser risk of autoimmune disease from a few high-risk genetic variations, and a greater risk of random selection from the common genetic variants, each having a weak effect. Heel goes on to say that the genetic risk likely comes from inheriting a large amount of common variants from both parents. This would mean that it would be nearly impossible to test individually for such diseases. However, scientists are started to grasp the biological basis for the conditions that cause these diseases, opening a pathway for researchers to follow, hopefully leading to new drug avenues and possible treatment options.

By Lauren Horne
Sources:
    Queen Mary, University of London (2013, May 22). Largest genetic sequencing study of human disease. ScienceDaily. Retrieved May 23, 2013,
 
 
The search for signs in the human body that can be effective in screening and preventing Alzheimer’s disease (AD) is never ending. In a recently published on the online issue of Neurology, the medical journal of the American Academy of Neurology, on July 18th, researchers from Mayo Clinic, John Hopkins University School of Medicine, and Columbia University share their findings of about the series of serum ceramides that are possibility linked with the development of AD. Previous studies have associated serum ceramides with memory impairment and volume loss in the hippocampus. This cohort study involved two types of fatty molecules, sphingomyelins and ceramides. Ceramides are involved in the production of the precursors of amyloid, which can form into insoluble plaques in the brain and lead to AD. The participants were 99 women in the Women’s Health and Aging Study II, and all were without dementia and within the age range of 70 to 79. Their blood was tested, and levels of sphingomyelins and ceramides were measured. They were split into three groups, high, middle, and low, based on the levels of ceramides in their blood. All 99 were registered to be in a prospective study and checked on for up to six visits over nine years. The results showed that 27 of the 99 participants had developed incident dementia, and of the 27, two-thirds received a diagnosis of probable AD. In relation to the level of ceramides found in their blood, those in the high group were ten times at risk for AD than those in the low group, while those in the middle group were eight times more at risk.

These results are significant, as they are consistent with previous research and could possibly provide an economical, convenient, and accurate biomarker for AD. Further studies will need to be conducted with a larger and more diverse study group to confirm these findings.

Keywords: Alzheimer’s disease; serum ceramides; biomarker

Sources: http://www.neurology.org/content/early/2012/07/18/WNL.0b013e318264e3e2.excerpt

               http://www.neurology.org/content/early/2012/07/18/WNL.0b013e318264e380.abstract

Wendy Liu

July 25, 2012