US scientists have uncovered the genetic basis of a form of sudden infant death syndrome (SIDS) - or 'cot death' - associated with testes abnormalities. Team leader Dietrich Stephan says the findings, which will appear in the Proceedings of the National Academy of Sciences, could help save some babies at risk of sudden death.
The scientists studied nine families from an American Amish community, who between them had 21 babies who had died suddenly before the age of 12 months. They looked at DNA samples from four of the affected infants, and found that all had inherited two faulty versions of a gene called TSPYL. The researchers think the genetic change affects the control of the nervous system, which in turn causes severe heart and breathing problems.
Although several gene alterations are known to be linked with an increased risk of SIDS, this is the first gene identified that causes a primary form of cot death. The researchers, based at the Translational Genomics Research Institute in Phoenix, Arizona, have named the new form sudden infant death with dysgenesis of the testes (SIDDT). Baby boys with SIDDT may have underdeveloped testes, but baby girls appear normal, and have normal hormone levels. 'This is one of the first genetic sub-classifications of SIDS', said Stephan, adding that 'it's going to be helpful in offering parents answers for sudden infant deaths, recognising predisposition early, and hopefully saving a number of these babies'.
Although the study looked at SIDS in an isolated community, Stephan says that 'all of the disorders that are present in the Amish communities are also present in the general population, just at a lower frequency, both in the US and in the UK'. In 2002, a total of 342 British babies under the age of two died from SIDS.
The study also highlights the increasing speed with which new disease genes can be identified, using DNA 'chips', or microarrays, which enable researchers to look at thousands of different genetic variations at the same time. Using chip technology, the scientists say they pinpointed the TSPYL gene in less than two months.