Sudden infant death syndrome may have genetic basis in some cases, study suggests

The mutation causes a dysfunction in which can make in which harder for infants to adequately respond to hypoxemia, or low oxygen levels inside the blood, the researchers said. in which alters the shape of a “sodium channel” in which maintains an electric current to stimulate muscle contraction.

“I think the evidence is actually pretty compelling in which some cases of SIDS are caused by sodium channel mutations,” said Dr. Michael Hanna, a professor of clinical neurology at University College London along that has a leading author of the study.

“There must be a vulnerability, along with what we’re saying is actually in which in some cases, the sodium channel is actually rendering them vulnerable.”

Sudden infant death syndrome refers to the unexpected along with unexplained death of a seemingly healthy infant between 1 month along with 1 year of age, often while the child is actually asleep. The syndrome accounts for nearly 2,400 infant deaths every year inside the US along with is actually the leading cause of death in in which age group in high-income countries, according to the National Institutes of Health.

The phenomenon has long been known to be associated with sleeping positions, such as when babies sleep on their stomachs, along with second-hand exposure to cigarette smoke, according to Hanna.

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“There’s a big campaign in America along with in Europe called the Back to Sleep campaign in which’s been running for some years,” he said. “Basically, just the act of putting a baby on their back to go to sleep instead of the front reduces the incidence of these deaths by about 60%.”

nevertheless in which study would likely be among the first to show in which a dysfunction inside the electrical activity of skeletal muscle could also be a contributing factor, says Dr. Stephen Cannon, a neurologist along with professor of physiology at the David Geffen School of Medicine at the University of California, Los Angeles, who was not involved inside the research.

“in which’s a very convincing set of data,” Cannon said. “inside the preceding four or 5 years, there have been cases recognized where muscle defects cause breathing difficulties in (newborns) along with young children, so in which was kind of a logical extension in which in which might go on to progress to something like SIDS.”

The researchers compared the genomes of 278 children inside the United States along with United Kingdom who died of SIDS with 729 ethnically matched controls. They found in which an extremely rare mutation in a gene called SCN4A was present in four of the 278 cases of SIDS nevertheless none of the controls.

The SCN4A gene codes for a sodium channel responsible for maintaining the electrical current in which stimulates skeletal muscles, such as those responsible for breathing. A disruptive mutation in in which gene would likely normally be expected in fewer than one in every 100,000 individuals, according to Cannon.

“The odds of seeing four in a group of 300 is actually just astronomical. There’s no way in which’s going to happen by chance,” Cannon said. “The numbers are tiny, which is actually a challenge, nevertheless in which’s what happens with extraordinarily rare disorders.”

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A mutation inside the SCN4A gene has been linked to skeletal muscle disorders in adults. These disorders are typically characterized by an inability to effectively stimulate or relax skeletal muscles, resulting in excessive muscle stiffness or weakness.

The shared genetic basis between these adult muscle disorders along with some cases of SIDS could impact the screening along with counseling of prospective parents with known skeletal muscle disorders, Cannon suggests.

“An interesting spin off to in which study is actually whether the couple of thousand people who have these inherited muscle diseases inside the United States should be advised along with whether we should change the recommendations for how their infants are cared for,” he said.

However, Hanna cautioned in which the mutation was found in only 1.4% of the infants who died of SIDS, meaning the vast majority of cases are still probably caused by a host of additional factors. “I think in which’s probably a major factor, nevertheless in which’s not a sole factor,” he said. “along with what the additional factor might be could be one of these environmental triggers,” like smoke exposure.

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Because the study looked at only one ion channel, future research may want to look at similar mutations in additional channels, according to Hanna.

“The respiratory muscles probably have about a hundred different ion channels in which are ultimately responsible for normal contraction along with relaxation of respiratory muscles. We’ve just looked at one channel because in which was where our hypothesis took us,” Hanna said.

“The next step is actually to look at all the additional channels,” he added. “in which obviously requires further research into all these additional genes.”

The study looked exclusively at children with European ancestry, so the results may not be generalizable to people by additional ethnic backgrounds. African-Americans, for example, are known to have an increased risk of SIDS, which may or may not be attributable to in which genetic mutation, Cannon said.

What in which means for the future of SIDS prevention is actually unclear. nevertheless some medications, including sodium-channel blockers such as mexiletine, may play a future role in managing those infants at higher risk of SIDS, according to Cannon.

“There are already medications available in which can inhibit or block sodium channels along with could therefore be very beneficial to get the patient past the period of vulnerability,” Cannon said.

“Just knowing in which’s inside the family, you could also be more vigilant about monitoring or additional preventative measures in which have been used in SIDS along with additional cases — for example, careful positioning of a baby’s sleeping,” he added.

Source : Sudden infant death syndrome may have genetic basis in some cases, study suggests