It is a silent genetic condition affecting millions of people, dramatically increasing the risk of heart attacks and strokes. Yet vanishingly few have ever heard of it.

Lipoprotein(a), or Lp(a), is a type of ‘bad’ cholesterol that causes no symptoms and is not detected by standard testing and checkups.

Around one in five people inherit high levels, often without knowing, and many are not diagnosed until they suffer a serious cardiovascular event.

Some die without ever discovering they were living with the hidden risk.

Last week, The Inbetweeners star James Buckley revealed on his podcast he is among those with dangerously high Lp(a) levels, after a blood test uncovered the condition.

Speaking on The Buckleys, which he hosts with his wife Clair, the actor said: ‘I’m at a high risk now for a cardiovascular incident. I’m not a religious man, but sometimes I feel like there is a God that sort of goes, “That’ll teach you.”

‘There’s nothing you can do about it, by the way. And the doctor’s just been like, “You need to change.” ’

Last week The Inbetweeners star James Buckley revealed on his podcast he is among those with dangerously high Lp(a) levels

As James points out, there is no medication which can treat the condition. Since being diagnosed, he has instead overhauled his lifestyle, including cutting back on alcohol.

But how much difference can this actually make? And could you be among the millions of people to inherit high levels of Lp(a) without knowing it?

Here, our experts tell you everything you need to know about the condition, the new drugs in the pipeline and – if you do have it – how to manage it to significantly reduce your risk.

What is Lp(a) and where does it come from?

Lp(a) is a type of cholesterol particle made naturally by the liver. Scientists believe it may play a role in helping repair damaged blood vessels and aid wound healing, meaning everyone has some in their bloodstream.

The problem is that about one in five people inherit genes that cause them to produce far more Lp(a) than normal. Unlike LDL – or low-density lipoprotein – the more familiar ‘bad’ cholesterol that is largely influenced by diet and lifestyle, Lp(a) levels are almost entirely determined by genetics.

At high levels, Lp(a) behaves much like LDL, sticking to artery walls where it fuels inflammation and the build-up of fatty plaques that narrow blood vessels and raise the risk of heart attacks and strokes. It may also make blood more likely to clot, further increasing cardiovascular risk.

Despite affecting millions of people, Lp(a) is not routinely tested for on the NHS because its role in heart disease has only relatively recently become clear.

A study published in 2009 found that people with genetic variants causing high Lp(a) levels faced almost double the risk of cardiovascular disease. That evidence has prompted a growing campaign for Lp(a) testing to be added to routine NHS Health Checks for over-40s in the UK, with experts arguing that identifying those at risk could allow them to take steps to reduce their chances of suffering a heart attack or stroke.

Isn’t it the same as having high cholesterol?

No. High cholesterol usually refers to raised levels of LDL – the ‘bad’ cholesterol that is strongly influenced by diet, weight, exercise, smoking and alcohol.

Lp(a) is different. Your level is determined almost entirely by the genes you inherit, meaning healthy eating, regular exercise and weight loss have little effect.

It is also more dangerous than LDL because every Lp(a) particle carries an extra protein called apolipoprotein(a), or Apo(a), which makes it particularly effective at burrowing into artery walls, triggering inflammation and accelerating the build-up of fatty plaques.

Because people are exposed to high Lp(a) from birth, that damage can accumulate over decades, meaning heart attacks and strokes can strike much earlier than expected – often before 60.

For many people, the first sign of the condition is having a heart attack or stroke early in life

‘It’s nastier because of that extra protein tail,’ says Professor Kausik Ray, a cardiologist and professor of public health at Imperial College London. ‘If LDL is like taking 100 bullets to your arteries, Lp(a) is more like a bazooka – there’s much less of it around, but it does more damage.’

Cardiologist Dr Ravi Assomull adds: ‘Unlike other types of cholesterol, you can’t diet or exercise your way out of this.

‘Some particles can stick to the artery walls and detach – this doesn’t. It invades the vessel wall, causes inflammation and then the formation of plaque which can potentially rupture, causing a clot to form and a heart attack.’

Could I have high Lp(a)?

Possibly, and it takes a specific blood test to find out.

Like high cholesterol, it has no symptoms, and a standard cholesterol test from your GP or pharmacy does not test Lp(a) levels.

Regina Giblin, senior cardiac nurse at the British Heart Foundation, says: ‘Even if your cholesterol test comes back completely normal, you can still be living with elevated Lp(a).’

For many people, the first sign of the condition is having a heart attack or stroke early in life.

But there are signs to look out for in your own family, including other close relatives who have high Lp(a).

‘If there is a high incidence of heart disease from a young age in your family, perhaps even heart attacks in relatives who are in their early 40s or even late 30s, then it’s worth thinking about getting a test for inherited high cholesterol diseases,’ says Ms Giblin.

A single blood test is all it takes, and because Lp(a) levels are largely fixed from birth, it usually only has to ever be done once.

How can I get tested?

THIS isn’t something your GP can do – you need to be referred to a specialist lipid clinic or get a private test.

Private at-home tests cost around £45, while private clinics charge anywhere from £65 to £130.

It involves a simple blood test, which is then analysed for Lp(a) levels. However, at the moment, the National Institute for Health and Care Excellence (NICE) does not recommend routinely testing people for Lp(a).

Prof Ray says: ‘We’ve got a bit of work to do in terms of getting access to the test, and there’s even a postcode lottery when it comes to hospitals using it. That needs to change. I think everybody should be tested once in their lifetime.’

A taskforce spearheaded by cholesterol charity Heart UK is calling for increased recognition of Lp(a) as a cardiovascular risk factor, and to consider adding it to the QRISK tool which doctors use to calculate an individual’s ten-year risk of a heart attack or stroke.

Does it mean I’m definitely going to have a heart attack?

NO, but it does make it significantly more likely, says Prof Ray.

Having more Lp(a) can increase the risk of atherosclerosis, a condition which involves the furring of the arteries, coronary heart disease, strokes, peripheral arterial disease, aortic valve disease and heart failure. And studies show the higher your Lp(a) levels, the greater the risk – over a certain rate may more than double the risk.

But crucially, it is all relative.

If you’re otherwise healthy and fit, with no other risk factors, doubling your risk may take your lifetime risk of a heart attack or stroke from 5 per cent to 10 per cent, for example – not a hugely significant increase given one third of people will die from cardiovascular disease.

Prof Ray says: ‘Don’t freak out if your number is high. There is nuance, based on other factors that also influence heart health, from whether you have high cholesterol, high blood pressure and type 2 diabetes, to whether you smoke and drink heavily, to your diet, your weight and whether you exercise.’

Are some people more at risk?

YES – some ethnic groups might be more likely to inherit the condition. ‘People with Afro Caribbean or South Asian heritage might have higher levels of Lp(a), while people from places like China and Japan may be less at risk,’ Dr Assomull explains.

Other conditions can also cause Lp(a) levels to rise, such as chronic kidney disease, nephrotic kidney disease, and hyperthyroidism. Levels may also increase for some women during pregnancy or after menopause, although Prof Ray says there is not enough evidence to know for certain how this affects risk, or to explain why.

What can I do about it – can I just take statins?

YOU can take a statin, but it won’t lower Lp(a). In fact, it can even raise levels slightly.

What statins do lower is LDL cholesterol, reducing overall cardiovascular risk.

Some studies also suggest they may shrink Lp(a) particles, says Ms Giblin, although it isn’t yet clear whether this improves outcomes.

Another option is a class of drugs called PCSK9 inhibitors, including Repatha and Praluent. Licensed to prevent heart attacks and strokes by lowering LDL cholesterol, they also cut Lp(a) by around 25 per cent, says Dr Assomull. On the NHS, they are reserved for people whose LDL remains high despite statins, or who cannot take them.

A final option is apheresis, a dialysis-like procedure that filters cholesterol from the blood. Because it carries risks, including blood clots, it is generally reserved for the highest-risk patients.

Are better treatments on the way?

Yes. Several drugs designed specifically to lower Lp(a) are in the final stages of clinical trials and could reach the NHS within the next five years.

Among the most promising is lepodisiran, a twice-yearly injection that blocks the liver from making Lp(a). In a major trial, it cut levels by up to 94 per cent, with some patients’ Lp(a) becoming undetectable.

Another treatment, pelacarsen, lowers Lp(a) by around 80 per cent and is also in late-stage international trials, including in the UK, with results expected this year.

Other new cholesterol drugs may also help.

Last month, the FDA approved enlicitide (Lipfendra), which lowers LDL cholesterol but also cuts Lp(a) by about 28 per cent.

Obicetrapib, which could reach the UK by the end of the year, appears to reduce Lp(a) by 40 to 50 per cent.

The remaining hurdle is proving that lowering Lp(a) translates into fewer heart attacks and strokes.

‘We’ve still got to show that lowering Lp(a) modifies outcomes,’ says Professor Ray. ‘But the landscape could change considerably over the next few years.

‘The next step is then gene-editing therapies.’

Is there anything I can do to protect myself?

THIS is the good news. While you can’t lower Lp(a) itself, experts say you can substantially reduce your overall cardiovascular risk by tackling the factors you can control.

‘Lp(a) is only one piece of the puzzle when it comes to cardiovascular risk,’ says Dr Assomull. ‘It’s worth thinking about it as a useful wake-up call.’

That means quitting smoking, drinking alcohol only in moderation, controlling blood pressure and maintaining a healthy weight.

Diet also matters. Ms Giblin recommends a Mediterranean-style diet rich in fruit, vegetables, wholegrains, fish, nuts and seeds, while cutting back on red meat and processed foods.

Exercise is equally important. The NHS recommends at least 150 minutes of moderate activity a week, while Dr Assomull says regular resistance training can also help by lowering LDL cholesterol and triglycerides – a type of fat – and improving blood pressure and blood sugar.

‘People often assume this is a death sentence,’ says Professor Ray. ‘But no one single factor is going to predict that you’re going to have a problem, and there is a lot you can do to protect yourself.’