Researchers have reported findings suggesting that a rare genetic mutation may play a role in some cases of sudden infant death syndrome (SIDS). Researchers at the Chinese University of Hong Kong and the Medical College of Georgia in Augusta say the genetic mutation, OCTN2, apparently causes a deficiency in carnitine, a fatty acid-transporting substance that plays a key role in cellular metabolism. The researchers say that primary carnitine deficiency is a genetic disease found in only 40 families worldwide. The OCTN2 mutations was reportedly found in a child whose death was attributed to SIDS, the second such sibling to die of SIDS. It was further found that the parents of the children also carried the mutation, but that a third sibling, who did not die, did not carry the mutation. Authors say primary carnitine deficiency causes no apparent symptoms in either adults or infants, but that affected children may be at increased risk of death prior to the age of one year. The research was reported in the journal "Human Molecular Genetics" (1999;8:655-660).