Another 'bad' type of cholesterol that contributes to heart disease has been discovered by scientists at Oxford University.
Lipoprotein(a) or Lp(a) cannot be controlled by cutting down on dietary fats or taking a statin drug, unlike the well-known LDL cholesterol.
However, researchers say high levels do not carry the same risk as LDL and other drugs might work to minimise its effects.
LDL is considered the aggressive tiger of the cholesterol world, furring the arteries and greatly increasing heart risk.
The research into Lp(a) found that levels of cholesterol appear to depend on our genes.
Study's lead author Professor Martin Farrall and colleagues used gene-chip technology to scan DNA that they knew from previous studies were potential "hotspots" for heart disease risk. This analysis revealed the two genetic culprits.
Farrall said one in six people carries one or more of the genes for Lp(a)."The increase in risk to people from high Lp(a) levels is significantly less severe than the risk from high LDL cholesterol levels," the BBC quoted him as saying.
"So Lp(a) doesn't trump LDL, which has a larger impact and which we can already control pretty effectively.
"The hope now is that by targeting both we could get even better risk reduction," he added.
The study has been published in the New England Journal of Medicine.