Genetic Testing Could Predict What Age People Develop Alzheimer's Disease

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Scientists suggest that the risk of developing Alzheimer's disease (AD) can now be calculated through genetic information. They create a genetic test that could compute the age a person is likely to develop this most common cause of dementia.

Researchers at University of California San Diego School of Medicine and University of California San Francisco led the study. According to Science Daily, an international group of scientists examined genotype data of single nucleotide polymorphisms (SNPs) that are linked with Alzheimer's disease. These SNPs are mutations of one nucleotide or DNA building block, which influences the susceptibility of people to a certain disease.

In this case, the scientists observed the association between SNPs, and Alzheimer's disease risk and Apolipoprotein E (APOE) grade. They then discovered that people with an E4 variant in their APOE gene are more likely to develop late-onset of the disease.

Furthermore, the scientists formulated a constant polygenic hazard score (PHS). They found people with high PHS to have developed Alzheimer's disease earlier than expected and an elevated annual progression of the condition.

In addition, people without APOE E4 allele but with an increased PHS could develop Alzheimer's disease 10-15 years earlier as compared to low-scorer counterparts. The authors discovered that PHS suggests firmly age of AD onset based on the findings. The validation and description of the PHS system are published online in the journal PLOS Medicine on March 21.

The scientists integrated genetic data from a large group of patients suffering from Alzheimer's disease with an epidemiological assessment to make the scoring. “We then replicated our findings on an independent sample and validated them with known biomarkers of Alzheimer's pathology," Rahul S. Desikan, MD, Ph.D., co-first author and clinical instructor in the UCSF Department of Radiology & Biomedical Imaging said.

The scientists combined precisely polygenic data obtained from genotype with known incidence rates of Alzheimer's disease from the United States population. From the information, they obtained a risk score of developing AD.