Genetic mutations that affect vital body functions are linked to an increased risk of cot death, a new US study shows. Researchers at the Rush University Medical School in Chicago studied DNA from 92 babies who had died of sudden infant death syndrome (SIDS), and 92 healthy babies. They looked at genes involved in the development of the autonomic nervous system, which controls processes such as breathing and heartbeat, and found that mutations in these genes were far more common in the SIDS cases, particularly in African American babies.
The scientists found 11 different mutations in 14 of the SIDS cases, but only one mutation in two of the healthy babies. Team leader Debra Weese-Mayer said that 71 per cent of the SIDS cases that had the mutation were African-American, as were both of the healthy babies. 'Knowing that SIDS incidence is significantly higher in African-Americans gives strong support for a the possibility of a genetic basis', she concluded. She thinks that mutations affecting regulation of the nervous system may mean that heart and breathing rate may not be able to react quickly enough to a stressful situation, causing these functions to 'simply shut down'.
The study, published in the journal Pediatric Research, sheds further light on the possible underlying causes of SIDS. Education campaigns in both the US and UK to teach parents to put babies to sleep on their backs has reduced the number of SIDS cases, but has not eradicated them. 'We've had too many parents who came to us and said 'look, we did everything right - we got the best prenatal care, no-one smoked anywhere near the baby, we put her down on her tummy and still she died', said Weese-Mayer, adding 'that led us to say there has to be a genetic basis'.
Earlier this year, another US team identified a gene mutation linked to cot death and genital malformation in an American Amish community, which also affected control of the nervous system.