Babies who die from Sudden Infant Death Syndrome (SIDS), are more likely to have rare genetic mutations associated with weaker breathing muscles.

SIDS

Also known as cot death, SIDS is the unexplained death of seemingly healthy babies less than a year old. It often occurs during sleep.

The cause of SIDS is still unknown, but there are some factors that may increase a baby's risk such as brain defects, low birth weight, and respiratory infections. Maternal risk factors such as use of drugs or alcohol and sleep environmental factors, which include the baby's sleeping positions and items in the crib, are believed to contribute to a child's risk.

Findings of a new study now reveal another factor that may help identify babies at risk for SIDS.

Rare Genetic Mutation

In a new study published in The Lancet, Michael Hanna, from University College London, and colleagues looked at the tissue samples of 278 children whose deaths were unexplained.

The DNA from the samples were compared with those from 729 healthy adults without history of lung, heart, and neurological disease.

Hanna and colleagues found a rare mutation in the SCN4A gene in four of the children but none in the adults. The SCN4A gene plays a role in regulating muscle control. Mutations can cause a number of conditions, which include spasms that can make breathing and speaking impossible.

Although the researchers found the mutation in only a small number of the children's DNA samples, the finding is still significant because SCN4A mutation is extremely rare, affecting fewer than five people in every 100,000.

The researchers think that this mutation can leave children with weaker breathing muscles more vulnerable when they sleep in the wrong position or get tangled in the bedclothes.

"We showed that rare variants that alter NaV1.4 channel function in a similar fashion to known pathogenic SCN4A variants were over-represented in infants who had died of SIDS compared with ethnically matched controls," the researchers wrote in their study.

Safe Sleeping Measures Still Essential For Babies

Treatments are currently available for genetic neuromuscular disorders caused by SCN4A gene mutations, but the researchers said that it is still not clear if these treatments can reduce the risk of sudden infant death syndrome.

Hanna and colleagues also stressed the faulty genes are likely not the only cause of cot death, and having safe sleeping measures can still ensure the safety of the baby.