WE all know that heart attacks sometimes run in families. It is generally
accepted that one third of the cases
are due to genes and two thirds due to the
environment – for instance, an unhealthy
lifestyle which includes a faulty diet, smoking
and a lack of exercise.
Studies show that heart attack rates are
low in countries like Japan where the diet is
low in fat.
When the Japanese migrated to Hawaii and
California, however, they became prone to
heart attacks. This showed that their former
protection against heart attacks was due to
the Japanese way of life rather than inheritance.
Among people who live in the same
country, there are differences in their rates of
cholesterol levels and heart attacks even
though their dietary habits do not differ very
Recent research indicates a differing susceptibility to the cholesterol-raising effect of
the fat and cholesterol in our diets.
The fortunate part is that those who have
this inherited susceptibility will also tend to
show a large fall in blood cholesterol level
when they reduce the amount of fat they eat.
These differences reflect the combined effect
of many genes of small-effects combined
The family prone to heart attack can also
reflect other risk factors such as diabetes mellitus, high blood pressure and obesity which
are, in part, inherited.
There are a few conditions that cause very high cholesterol as a result
of inheriting a single abnormal gene (monogenic). They run
strongly in the families and the disease may
not be apparent. Hence, cholesterol testing in
healthy people may pick up the condition.
One of these conditions is familial hypercholesterolaemia (FH). It occurs in one out of
every 400 people in this country.
In the current population of 26 million in
Malaysia, it is estimated that there are 65,000
people suffering from FH. Their blood cholesterol is high from birth and is about twice
that of a normal individual (8-10 mmol/L).
The average cholesterol in a normal
Malaysian is 5.2 mmol/L.
Cholesterol deposits in the skin and tendon
There are tell-tale signs of cholesterol
deposits in the skin and tendon known as xanthomas. The tendon behind the ankle
(tendo achilles) is thickened.
Less frequently, this pea-shaped swelling
over the knuckles is similar to those you find
on an individual who practices tae-kwan-do,
except that in FH, the overlying skin is normal.
About 50% of FH patients have these signs
and the only way to be sure of the diagnosis
is to take a blood sample and measure their
levels of cholesterol and triglycerides.
Other less reliable signs
Arcus cornealis is a white ring or crescent
over the outer part of the cornea of the eye. It
is only reliable if the patient is tinder the age
of 30 years and does not have a current eye
These are yellow flat spots on the eyelids.
Only 50% of individuals with these spots have
Familial hypercholesterolaemia is a condition
that is strongly inherited. One parent is always
affected and about half of the offspring will
carry the gene and will be affected.
Thickened knuckle tendons – a sign of
It is important to reduce the intake of
cholesterol-rich foods and saturated fats,
while consuming foods which inhibit the
absorption of cholesterol in the gut.
Many people think that going on a cholesterol-free and saturated-free diet is fine.
Unfortunately, the liver produces 800mg of
cholesterol daily and this is excreted in the
About 50% is reabsorbed in the terminal
ileum. Foods that inhibit cholesterol absorption such as plant, stanol and sterol and
beta-glucan (oat soluble fibre found in oats)
can help lower the cholesterol.
Taking cereals can replace fat intake and
inhibit the absorption of cholesterol from
Statin drugs are favoured because they
are very effective and produce the least
side-effects. Bile acid sequestrants will
lower cholesterol by inhibiting the re-absorption by bile acid
LDL-C apheresis is indicated in
cases where cholesterol isn't successfully lowered to the target desirable
levels despite maximal diet and drug therapy.