Heart gene linked to cot death

Babies should be put to sleep on their backs

Scientists believe they may have discovered a cause of unexplained deaths in apparently healthy babies.

They hope the breakthrough could eventually lead to measures to prevent cot death, or sudden infant death syndrome (SIDS).

This study attempts to make SIDS less of a mysterious black box

Dr Michael Ackerman

The researchers, from the Mayo Clinic, Rochester, US, believe that in some cases SIDS is linked to a gene called SCN5A.

This gene helps controls how heart cells use sodium to regulate their electrical rhythm.

Researcher Dr Michael Ackerman said: "This is step one of many that could eventually prevent SIDS.

"This study attempts to make SIDS less of a mysterious black box.

"We're just starting to be able to identify those infants that may be at risk for SIDS and take steps to prevent the incidence of death."

Heart syndrome

How to reduce the risk

place baby on the back to sleep

cut smoking in pregnancy

don't let anyone smoke around baby

don't let baby get too hot

keep your baby's head uncovered

position to prevent wriggling down under the covers

if baby is unwell, seek medical advice promptly

keep the cot in the parental bedroom for the first six months

avoid falling asleep on the sofa with your baby

The gene is associated with long-QT syndrome, a heart irregularity that can cause sudden death.

People with long-QT syndrome can faint or even die while resting or sleeping.

Dr Ackerman said that deaths associated with the gene could easily go undetected because there would be no obvious clues when a post mortem was carried out.

However, he warned that the gene was only one of many that controlled heart rhythm, and others might also play a role in SIDS.

Dr Ackerman's team looked at cells from the hearts of 93 babies who died of SIDS.

Two of the babies had defects in the SCN5A gene.

Dr Ackerman said this is a low percentage but other, related genes may be involved that explain more of the cases.

He said: "A theory, and this is only a theory, is that perhaps sleeping on the stomach is more likely to cause a long QT heart to spin electrically out of control.

"Maybe because when sleeping on its back a baby is less likely to have breath-holding spell."

Other research

Many cot deaths may have no basis in genetics

Foundation for the Study of Infant Deaths

The Foundation for the Study of Infant Deaths (FSID), the UK's leading cot death charity, said it was also carrying out research into the possibility of a genetic background to some cot deaths.

In a statement it said: "Some cot deaths may be due to a single gene, others may be explained by different genes affecting how the body reacts.

"However, many cot deaths may have no basis in genetics.

"UK research has shown a gene affecting a baby's immune response to infection was found in a number of babies who died as cot deaths."

A campaign to encourage parents to put babies to sleep on their backs cut the rate of SIDS deaths by nearly half in the US and Britain.

The only other known cause of SIDS is a defect in liver enzymes, blamed in about 5% of cases.