Doctors are able to predict the risk of contracting most diseases, but not the dreaded Alzheimer’s disease. It is believed that the disease start its devastating process as early as 10 to 20 years before the actual onset of the symptoms. The researchers have recently identified a gene that may provide a vital clue to this puzzle.

A team of researchers at Duke University Medical Center, headed by Dr. Allen Roses, has discovered the gene, hence named Tomm40. The gene was helpful in predicting the onset of the disease within 5-7 year span in people above 60 years. Roses laid the foundation of this new study. He found in a previous study that presence of apolipoprotein E (APOE) variants, especially APOE4, makes the carriers of the gene susceptible to AD. The two genes, APOE4 and TOMM40 together, account for a staggering 85-90% of AD caused by genetic reasons.

TOMM40 gene has both long and short versions, with the longer one being more deadly. The APOE4 gene always accompanies it. Those with APOE3 gene may have long or short versions of TOMM40. If a person having APOE3 with two long TOMM40 genes, may start exhibiting the symptoms of AD by the age of 70. Those with one long and one short version may get an additional seven years of AD-free life, while the people with two short TOMM40s may not develop AD at all.

With this information, doctors can evaluate the chances of AD and age of onset, based on the genetic analysis. However, before actually going public, validation of findings with larger numbers needs to be done. The team is planning to do exactly this.

The Duke team is preparing for a five-year study of the APOE and TOMM40 genes. They are also including a drug trial to delay the onset of AD.

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