The molecule researchers at Baylor are concerned with is carnitine, specifically the decreased production of carnitine due to a deletion in the gene trimethyllysine hydroxylase epsilon (TMLHE) responsible for the first enzyme in a biochemical reaction that eventually yields carnitine. Carnitine itself is involved in the transport of fatty acids to mitochondria (essentially cellular energy production). It is currently being postulated that the carnitine deficiency is linked to autism and in certain cases carnitine supplements may help. However, these results are still preliminary and how they are related is not yet understood.
Male subjects were the focus of the study as they only have one copy of the X chromosome (where the gene deletion takes place) and are more likely to exhibit symptoms. As it stands 1 in 366 males have the deletion and about 3 percent are then found to have autistic characteristics. Strangely, there was no link found with families that have only one autistic child or families with both an autistic boy and girl. But, in families with two autistic male children they are 2.82 times more likely to have the deletion. When moved to a larger sample study focused only on male pairs, the results rose to 7.7% with autism & the deletion and 2.7% for only the deletion.
The researchers now want to broaden their search for carnitine deficiencies beyond this gene deletion to determine what role carnitine might be playing. Douglas Wallace, not affiliated with the research but director of the Center for Mitochondrial and Epigenomic Medicine at the Children’s Hospital of Philadelphia, say these findings fall in line with his recently published work on broad cellular energy defects, neuronal connections, and ion transport.