Generales

The town of Yarumal, in Colombia, became famous for being home to the world’s largest population of Alzheimer’s sufferers. The clan has been described by some scientists as a “natural laboratory” for the study of this type of dementia.     

Half the population of the town of Yarumal, Colombia, are likely to develop Alzheimer’s or “bobera” (foolishness), as locals call the disease.

This extended Colombian family consists of 5,000 people, half of whom will contract the disease at the early age of 45 or before, while the remaining half will develop Alzheimer’s about the age of 65 according to medical researchers.   

Therefore, scientists from around the world undertook the task of studying the so-called paisa mutation, a rare genetic mutation that is responsible for the disease. 

All of the family members are descendants of a Spanish conquistador who settled in the area in the early 17th century, who is also believed to be responsible for introducing the mutation that causes Alzheimer’s. 

In 2011, Dr. Francisco Lopera, the Colombian neurologist who discovered the mutation, told BBC News that genetic testing could hold key to find a cure for Alzheimer’s sufferers worldwide.

Scientists say they have found a network of genes and their subsequent mutations that either speed up or delay the onset of Alzheimer's disease.

All of the clan members (5,000 people) are descendants of a Spanish conquistador who was responsible for introducing the mutation that causes Alzheimer’s, the 21st century plague. 

Dr. Mauricio Arcos-Burgos, a medical geneticist and associate professor from the John Curtin School of Medical Research (JCSMR) at the Australian National University (ANU), says that some members of the clan developed the disease in their thirties while other developed it in their seventies.

“This community has been so prompt to help the scientists and they have been very patient, they have been following all the recommendations of the neuroscientists, fundamentally Dr. Francisco Lopera, who has been in full contact with this family for the last 30 years, he knows each one of these patients as well as their history” the scientist told Newsday.

According to the researchers, the gene, also called E280A, delays the onset of the disease by 17 years. The so-called E280A is a form of the APOE gene that may help stop the progression of Alzheimer’s.

Yarumal, Colombia, was once famed for its violence. Today, it’s famous for a different reason: the largest population of Alzheimer’s sufferers in the world

The apolipoprotein E (APOE) gene plays an important role in preventing the development of plaques that stick to the brain. Scientists believe that the mutation of this gene may help improve the defensive properties of APOE.

Researchers aim to develop a drug that can mimic the properties of APOE in order to curb the spread of this devastating disease, which is the most common form of dementia worldwide.

“If we succeed in decelerating the disease we will achieve a major breakthrough in the fight against Alzheimer’s”, Dr. Arcos-Burgos said.

Fighting a one-of-a-kind disease

“Alzheimer’s is a very heterogeneous disease, so whenever you start doing research you come across a lot of types of Alzheimer’s,” the scientist said.  “But this one is unique because they have a unique mutation, they are located in a unique environment, they have a unique form of life, they have mostly the same culture, and then we saw something particular that is the most important part of this paper and is that the age of onset was very variable,” he added.

The study, which was recently published in Molecular Psychiatry, brought together scientists from Germany, Australia, Colombia and the United States.  

“I think it will be more successful to delay the onset of the disease than to prevent it completely. Even if we delay the onset by an average one year, that will mean nine million fewer people have the disease in 2050,” Dr. Arcos-Burgos said.

The scientists were able to isolate the nine genes associated with Alzheimer's, some of which delay the onset by up to 17 years, while others advance its progress.

“We found nine mutations in some genes that change completely the natural history of Alzheimer's. This breakthrough represents a huge step forward in research for Alzheimer's,” he said.

Alzheimer's facts & figures

Alzheimer’s kills at least 60,000 people each year worldwide. Over 99 percent of drug trials for the disease have failed. Therefore, scientists aim to prevent the onset of the condition rather than finding a cure.

These findings allow the researchers to better understand the disease. 

Alzheimer’s is a type of dementia that affects the ability to carry out simple tasks such as learning, remembering and reasoning. According to Alzheimer’s Society, the disease kills nearly 60,000 people each year.

There are an estimated 46.8 million people worldwide living with dementia in 2015. This number will almost double every 20 years, reaching 74.7 million in 2030 and 131.5 million in 2050.

So far, no drugs have been proven to slow or prevent the disease.

However, Dr. Arcos-Burgos appears optimistic and claims that “this is the first time that we are linking one form of the APOE gene to the delay of onset. We hope that this can be replicated”.