Tag Archives: gene

Scientists find sex gene risk for Alzheimer’s in certain females

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New York: A gene found on the X chromosome harbours the first sex-specific genetic variant linked to a greater susceptibility to Alzheimer’s, according to a new study.

Researchers at the Mayo Clinic in Jacksonville, Florida and Rochester, Minnesota showed that women who inherited the same variant of the gene, known as PCDH11X, from both parents were far more likely to develop the disease.

Among Alzheimer’s patients evaluated for the study, “the odds a women had two copies of the PCDH11X variant as opposed to no copies was nearly twice as high as for the control group,” the lead researcher, Steven Younkin, told AFP by email.

Both men and women with only a single copy were also slightly more likely to have Alzheimer’s. But only women have two X chromosomes, making them uniquely vulnerable to the impact of the double variant.

Men have one Y chromosome, and one X chromosome.

Alzheimer’s is a degenerative disorder of the brain characterised by forgetfulness, agitation and dementia. There is no known cure.

While many gene variants, or alleles, have been implicated in the onset of the disease, only one other — APOE 4 — has been shown to be a higher risk factor.

The findings, published in the journal Nature Genetics, do not necessarily mean that women as a whole are more prone to getting Alzheimer’s.

“There may be male-specific risk factors — genetic or environmental — that balance the increased risk in women from PCDH11X variant,” Younkin explained.

The researchers discovered the wayward string of DNA by scanning the entire genome of 844 patients and 1,255 healthy persons, looking for telltale markers that might point to a genetic culprit.

After identifying PCDH11X, they confirmed the “highly significant association” by repeating the gene tests on an even larger group of 1,547 patients, and a slightly smaller number of controls.

Follow up studies will investigate the exact mechanism by which the variant affects the nervous system in order to help diagnose the disease early on and develop suitable drugs, Younkin said.

Alzheimer’s is caused by a massive loss of cells in several regions of the brain, driven by a buildup of plaques of amyloid protein. The disease occurs most frequently in old age.

An estimated 37 million people worldwide live with dementia, with Alzheimer’s disease causing the majority of cases, according to the World Health Organisation (WHO).

With the ageing of populations, this figure is projected to increase rapidly over the next 20 years.

Scientists discover longevity gene

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New York: A gene variation that helps people live long lives also protects their memories and their ability to think and learn, say researchers from the US Institute of Aging Research.

The Albert Einstein College of Medicine in New York carried out a study of 282 older Ashkenazi Jews whose ancestors came from northern Europe found that those who had the gene variant were twice as likely to have good brain function as those who did not. The study looked at 158 people 95 and older and 124 people between the ages of 75 and 85.

The team discovered that the variant increases the size of cholesterol particles in the blood, making them much less likely to lodge in blood-vessel linings and cause heart attacks and strokes. They also thought the altered gene may protect against the development of Alzheimer’s disease, although they are not sure how it does so.

The report published in the Journal of Neurology says that scientists are currently trying to develop drugs to mimic the effect of the gene variation for people who don’t possess it.

New gene link to breast cancer

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London: A gene that puts women at an increased risk of developing breast cancer has been discovered by scientists.

They have identified that a faulty version of the BRIP1 gene means that those with it are twice as likely to develop the disease.

Other faulty genes such as BRCA1 and BRCA2 have already been linked with an increased risk. Those who carry these faulty genes have an 85 per cent risk of developing breast cancer and a 40 per cent risk of developing ovarian cancer.

Researchers from The Institute of Cancer Research in London decided to look at faults in the BRIP1 gene because it interacts with the known cancer-causing gene BRCA1.

According to the scientists, carrying a faulty version of BRIP1 doubles a woman’s risk of the disease – taking it from one in 12 to around one in six by the age of 70.

Don’t let your past kill your future – get tested at Britain’s first private patient gene clinic

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London: Genetic screening reveals a vital part of our life story: the part that was unknown until the discovery of the human genome – that is all the genes in each individual cell responsible for life. Now for the first time with genetic testing you can discover which genes you have been handed down – those responsible for protecting your body and which ones have the potential to harm you.

The aim of genetic testing is to foresee and with medical intervention prevent the “envelope of diseases” that may dispose certain individuals to debilitating and or life threatening illnesses such as heart disease, cancer, osteoporosis, diabetes and Alzheimer’s.

GeneticHealth is the first clinic in the UK – based in London’s Harley Street, to offer the latest scientific testing, analysis and medical intervention to prevent and protect individuals from the life-threatening diseases and illnesses they may have inherited.

The basis of GeneticHealth’s gene testing is a swab taken from the patient’s mouth which is used to analyse 45 genes that are clinically proven to have an effect on the way humans age and our resistance to age-related diseases. These are technically known as single nucleotide polymorphisms (SNPs) and, in particular, will tell you if you are prone to:

• Heart and cardiovascular disease
• Stroke
• Cancer
• Osteoporosis
• Obesity
• Diabetes
• Inflammation

Patients receive a 50-page report which examines in detail the state of their health, and includes a detailed results analysis and interpretation by our genetic doctors. Afterwards the client receives a medical consultation in which allows them to understand the implications of their individual genetic profile and what can be done to change their risk profile. GeneticHealth provides the opportunity for tailor made strategies to be developed to minimizing the risk of many of the diseases covered by the genetic analysis, especially cardiovascular disease. Your bespoke medical intervention programme is created with you by GeneticHealth’s medical experts.

The clinic’s Medical Director, Dr Paul Jenkins comments:

“I am convinced that the advent of effective genetic analysis will become increasingly relevant to individuals and clinicians seeking to minimise the burden of age-related diseases. For the first time, we are able to more accurately determine and individuals overall risk profile for many diseases by combining their genetic risk to that of lifestyle and environmental influences. Such an approach has enormous implications for healthcare and disease prevention in the 21st century.”

The results of the test are the basis for bespoke medical intervention including nutrition and other advice/therapies from the clinic’s experts. There are seven genetic tests to chose from and range in price from £180 to £825.

The clinic’s expert analytical team of medical experts and scientists in the field of genetics and healthy ageing includes:

• Dr Paul Jenkins MA, BChir, MD, FRCP – Reader in Endocrine Oncology, Honorary Consultant Physician, St Bartholomew’s Hospital, Queen Mary School of Medicine and Dentistry, University of London. He is Medical Advisor of the European Scanning Centre, which is one of only two centres in the UK to use an Electron Beam CT (EBCT) scanner. He leads an active research team and has published over 60 research papers in the field of hormones and genetic actions in the human body. He has a special interest in the role of genetics in disease prevention and ageing.

• Professor Stephen Bustin, BA,PhD – Professor of Molecular Medicine, Institute of Cell and Molecular Science, Queen Mary University of London. Stephen is a leading researcher in the genetic determinants of colonic cancer.

• Dr Lynette Yong, MAm MBBSm FRCSm LF Hom – Dr Yong studied medicine at Cambridge University and at St Mary’s Hospital, London. She completed her surgical fellowship in London with the Royal College of Surgeons of England. She has a special interest in the application of genetic analysis to the prescribing of hormones for men and women.

Patient information can be obtained by calling +44(0) 870 043 5551 email: info@genetic-health.co.uk

GeneticHealth is a clinically led company, based at 68 Harley Street, London W1, run by world-renowned doctors and genetic scientists. www.genetic-health.co.uk

Gene trigger for stem cell shut down in ageing

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Biologists have uncovered a gene that shuts down stem cells as people age.

They say the gene known as p16-Ink4a gradually reduces the ability of stem cells to proliferate, thus reducing the risk of cancer.

The discovery, reported in the scientific magazine Nature, was made in an experiment on mice, but the scientists believe that it applies to humans too.

The finding indicates that many degenerative diseases of ageing are caused by an active shutting down of the stem cells that renew the body’s various tissues and are not just a passive disintegration of tissues under daily wear and tear.

Senior author Dr Norman E Sharpless of the University of North Carolina said: “I don’t think aging is a random process — it’s a program, an anticancer program.”

The finding that stem cells are switched off with age is not encouraging for those who wish to use a patient’s own adult stem cells to treat disease.

The gene plays a central role in the body’s defenses against cancer, and it produces two quite different proteins that interact with the two principal systems for deciding whether a cell will be allowed to divide.

One of the proteins had also been noted to increase substantially with age. The cells of a 70-year-old produce 10 times as much of the Ink4 protein as those of a 20-year-old.

In the experiment the scientists genetically engineered a mouse strain with the gene knocked out. They found that the mouse cells had an extra ability to proliferate when the Ink4 protein was not present. At the same time the mice were highly prone to cancer which they developed as early as a year.

The researchers assume, but have not yet proved, that the increasing amounts of Ink4 as a person ages will thrust the stem cells into senescence, meaning that they can never divide again. The evolutionary purpose is evidently to avert the risk that a damaged stem cell might evade controls and proliferate into a tumor.

One implication is that therapists who hope to increase longevity have to tackle a system that may be hard to cheat. An intervention that reduces Ink4 production to prevent the age-related decline of stem cells will also increase the risk of cancer.

Dr Sharpless said that so far the only intervention known to increase lifespan was a calorically restricted diet which also reduced cancer, at least in laboratory mice. The reason, he said, is probably because such diets reduce cell division, the prime source of cancer risk.

For cell therapists, the dual activity of Ink4 may be “a hard box to get out of,” he said, unless they use cells that are somehow much younger than the patient.

Some proposals for stem cell therapy with adult stem cells envisage taking a patient’s stem cells, making them divide in the laboratory and putting them back in the patient to build new tissue.

The researchers said they did not yet know what stimulus makes cells increase their production of the Ink4 protein as a person grows older. Their suspicion is that the usual factors implicated in aging like mutation and oxidative damage to tissues would turn out to have a role in making cells produce more Ink4.