Tuesday February 19, 2019

Multi-gene Test May Help to Diagnose The Risk of Heart Disease, Diabetes And More

But specialists in heart disease and genetics who weren’t involved with the research called the new findings exciting because of their scope

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Gene test
Stephanie Richurk, a nurse at the University of Pittsburgh Medical Center, sorts blood samples collected from participants in the "All of Us" research program in Pittsburgh, Aug. 7, 2017. (VOA)

You know your cholesterol, your blood pressure … your heart gene score? Researchers say a new way of analyzing genetic test data may one day help identify people at high risk of a youthful heart attack in time to help.

Today, gene testing mostly focuses on rare mutations in one or a few genes, like those that cause cystic fibrosis or sickle cell disease, or the BRCA gene responsible for a small fraction of breast cancer. It is less useful for some of the most common diseases, such as heart disease or diabetes, because they are influenced by vast numbers of genes-gone-wrong working together in complicated ways.

Monday, researchers reported a new way to measure millions of small genetic variations that add up to cause harm, letting them calculate someone’s inherited risk for the most common form of heart disease and four other serious disorders. The potential cardiac impact: They estimated that up to 25 million Americans may have triple the average person’s risk for coronary artery disease even if they haven’t yet developed warning signs like high cholesterol.

“What I foresee is in five years, each person will know this risk number, this ‘polygenic risk score,’ similar to the way each person knows his or her cholesterol,” said Dr. Sekar Kathiresan who led the research team from the Broad Institute, Massachusetts General Hospital and Harvard Medical School.

If the approach pans out and doctors adopt it, a bad score wouldn’t mean you’d get a disease, just that your genetic makeup increases the chance — one more piece of information in deciding care. For example, when the researchers tested the system using a DNA database from Britain, less than 1 percent of people with the lowest risk scores were diagnosed with coronary artery disease, compared to 11 percent of people with the highest risk score.

heart disease
Multi-gene Test May Find Risk for Heart Disease and More. Pixabay

“There are things you can do to lower the risk,” Kathiresan said — the usual advice about diet, exercise, cholesterol medication and not smoking helps.

On the flip side, a low-risk score “doesn’t give you a free pass,” he added. An unhealthy lifestyle could overwhelm the protection of good genes.

The scoring system also can predict an increased risk of Type 2 diabetes, inflammatory bowel disease, breast cancer and an irregular heartbeat called atrial fibrillation, the team reported in the journal Nature Genetics — noting that next steps include learning what might likewise lower those risks.

It doesn’t require the most sophisticated type of genetic testing. Instead, Kathiresan can calculate risk scores for those five diseases — eventually maybe more — simply by reanalyzing the kind of raw data people receive after sending a cheek swab to companies like 23andMe.

A geneticist who specializes in cardiovascular disease, he hopes to open a website where people can send in such data to learn their heart risk, as part of continuing research. Kathiresan and co-author Dr. Amit Khera, a Mass General cardiologist, are co-inventors on a patent application for the system.

Other scientists and companies have long sought ways to measure risk from multiple, additive gene effects — the “poly” in polygenic — and Myriad Genetics has begun selling a type of polygenic test for breast cancer risk.

But specialists in heart disease and genetics who weren’t involved with the research called the new findings exciting because of their scope.

Cancer
Cancer Ribbon. Pixabay

“The results should be eye-opening for cardiologists,” said Dr. Charles C. Hong, director of cardiovascular research at the University of Maryland School of Medicine. “The only disappointment is that this score applies only to those with European ancestry, so I wonder if similar scores are in the works for the large majority of the world population that is not white.”

Hong pointed to a friend who recently died of a massive heart attack despite being a super-fit marathon runner who’d never smoked, the kind of puzzling death that doctors have long hoped that a better understanding of genetics could help to prevent.

“Most of the variation in disease risk comes from an enormous number of very tiny effects” in genes, agreed Stanford University genetics professor Jonathan Pritchard. “This is the first time polygenic scores have really been shown to reach the level of precision where they can have an impact” on patient health.

Also Read- Tdap Vaccinations Do Not Pose a Risk of Autism

First, the Boston-based team combed previous studies that mapped the DNA of large numbers of people, looking for links to the five diseases — not outright mutations but minor misspellings in the genetic code.

Each variation alone would have only a tiny effect on health. They developed a computerized system that analyzed how those effects add up, and tested it using DNA and medical records from 400,000 people stored in Britain’s UK Biobank. Scores more than three times the average person’s risk were deemed high. (VOA)

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Is Mammography Test to Spot Breast Cancer Necessary At All? Find out Here

The experts also recommended MRI, ultrasonography or a biopsy in which breast tissue or fluid is removed for laboratory testing, for younger women

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Breast Cancer
Nano technology offers hope for better cancer testing. Pixabay

A woman under 40, with no known breast cancer risk or visible symptoms of the deadly disease, need not take regular mammography tests, say health experts.

Accordingto the US Centers for Disease Control and Prevention (CDC), a mammogram is an X-ray picture of the breast, used as a screening tool for the detection of early breast cancer in asymptomatic women.

“If a woman doesn’t have symptoms of breast cancer then regular mammography tests before the age of 40 are not recommended,” Ramesh Sarin, Senior Consultant (Surgical Oncology) at Indraprastha Apollo Hospitals, New Delhi, told IANS.

If there is any lump in the breast, then mammography should be done.

“Those with increased risk (which is decided by clinician analysing multiple parameters) can begin screening at a younger age around 25-30 years,” added Upasna Saxena, Consultant (Radiation Oncology) from HCG Cancer Centre in Mumbai.

Cancer survivor, Flickr

In mammography, each breast is examined separately and compressed against the film to obtain maximum visualisation of masses or calcifications.

“This helps identify masses or lumps that are smaller than the size that can be felt on examination. Hence, they help in early detection of breast cancers. But at the same time all masses seen on mammography are not cancerous,” Saxena informed.

However, there are various concerns that mammography can be risky due to radiation. But experts noted that mammography uses low energy to take X-Ray of the breast.

“There are no risks which are associated with mammography, even if a woman gets 20-30 mammograms done in her lifetime,” Sarin said.

At the same time, “mammography is to be avoided in pregnant women as the foetus will be at risk even with minimal doses”.

Cancer
Cancer Ribbon. Pixabay

“If at all required in a pregnant woman, it can be done using a lead shield over the abdomen,” Saxena stressed.

Breast cancer is the most common type of cancer which affects women in India and, by 2026 the country will witness rise in the breast cancer incidence to 35 per 100,000 women as compared to the present rate of 25.8 per cent, says a Confederation of Indian Industry (CII) 2018 report titled “Breast Cancer Landscape in India”.

The cancer burden in India has more than doubled over the last 26 years, the highest increase among all therapy areas, with breast cancer being the most common among Indian women.

However, the National Family Health Survey (NFHS-4) data shows only 9.8 per cent women between the age of 15 and 49 in India have ever undergone breast examination.

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“Mammogram should be supplemented with monthly breast self-examination or breast awareness,” Saxena said, adding that breast self-examination once a month should start by the age of 20 onwards.

The experts also recommended MRI, ultrasonography or a biopsy in which breast tissue or fluid is removed for laboratory testing, for younger women.

“However, these alternatives are not as sensitive as mammography, wherein physical examinations can detect breast cancer only in 60-70 percent of the cases. But mammography can detect breast cancer with 85 per cent accuracy,” Sarin noted. (IANS)