Our brain is the most powerful link to the world and all things around us. Losing this connection costs precious memories and quality of life. The worst hit are those who suffer from a serious identity crisis – like in Alzheimer’s Disease – where they no longer recall who they are or their loved ones.
Awareness about Alzheimer’s Disease spread like wildfire in the 21st century, thanks to scientific advancement and global education. However, that was and never would suffice to match the increasing incidence rates for Alzheimer’s Disease in the general population. Inherited and sporadic cases of AD continue to be reported in India, along with other forms of senile dementia. The current prevalence of dementia (AD accounts for 60-80% of cases) is 7.7% in South Asia, which includes India.

Molecular changes at the cellular level cause Alzheimer’s Disease

Cognitive function, memory and other neurological functions progressively decline in Alzheimer’s disease. The formation of deposits (amyloid “plaques”) due to excess protein in the brain cortex is the key feature presented in clinical cases. Hallucinations, reduced communication fluency, short attention span, etc., are few symptoms exhibited by mild and severe Alzheimer’s Disease cases.

Alzheimer's disease

Types of Alzheimer’s Disease

  • Early-onset Alzheimer’s Disease (<5% of all cases): purely inherited (autosomal dominant mode) and is caused by mutations in the PSEN1/PSEN2 genes. These genes produce enzymes, which are responsible for the breakdown of amyloid precursor protein (APP). In the presence of genetic variations, APP accumulates in the brain and leads to Alzheimer’s Disease.
  • Late-onset Alzheimer’s Disease (majority of cases) – more complex in nature than early-onset AD. This phenotype is influenced by multiple genes. However, most studies have narrowed the strongest genetic factor to polymorphisms in the APOE (apolipoprotein) gene. One such variant is the epsilon (ὲ) – 4, which is so strongly linked with AD that the mere presence of this genetic defect is enough to confirm molecular diagnosis. Other genes of interest include TOMM40 and TREM2 — both these genes are implicated in key functions like cellular transport and inflammatory response (which is believed to protect against plaque formation).

Genetic Testing for Alzheimer’s Disease

Alzheimer’s has no known medical cure. One cannot pop a pill and erase symptoms. Constant surveillance and unconditional support is the single most important element for effectively managing this condition. For many Alzheimer’s Disease families, every day brings new hope for the next — regular and prolonged care is required and on many occasions, it might be demanding (physically and emotionally) to cope with affected members. All it takes is a deep understanding of what really goes on in the pathophysiology of Alzheimer’s Disease patients for truly stepping in their shoes and helping them along. In such cases, knowing how to prevent, delay and possibly reverse the disease is the best strategy. Preventive screening is the first step, especially for first-degree relatives. Genetic testing and counseling can help here.


Worried about Alzheimer’s? Mapmygenome can help you

Mapmygenome’s personal genomics tests Genomepatri and Brainmap can give your genetic predisposition to Alzheimer’s Disease and many more conditions. Our genetic counsellors can answer your queries regarding the hereditary aspects of Alzheimer’s Disease. We also offer diagnostic tests for Alzheimer’s, Dementia, and other syndromes. For more information, write to info@mapmygenome.in or call 1800-102-4595. Today!


About the Author

Rasika is the product specialist and scientific liaison for Mapmygenome’s personal genomics portfolio. With eight years of experience in sequencing, molecular biology, genetic data analysis and reporting, she currently works in the product team at Mapmygenome. Her key responsibilities include genomics product development, data curation, scientific content creation and management, data analysis and technical support for business development. Her key strength is a robust understanding of consumer genomics, including specialized areas such as pharmacogenomics, nutrigenomics and sports genomics. Rasika is also a certified group fitness trainer and Pilates (Balanced Body) Mat instructor.


References

  • World Alzheimer Report 2015- www.alz.co.uk
  • Corder E. H. et al. Gene dose of apolipoprotein E type 4 allele and the risk of Alzheimer’s disease in late onset families. Science 261, 921–923 (1993).
  • Potkin SG, Guffanti G, Lakatos A, et al. Hippocampal Atrophy as a Quantitative Trait in a Genome-Wide Association Study Identifying Novel Susceptibility Genes for Alzheimer’s Disease. Domschke K, ed. PLoS ONE. 2009;4(8):e6501. doi:10.1371/journal.pone.0006501.
  • Hickman SE, El Khoury J (2014). “TREM2 and the neuroimmunology of Alzheimer’s disease”. Biochem. Pharmacol. 88 (4): 495–8. doi:10.1016/j.bcp.2013.11.021.PMID 24355566

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