A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Winter, 2016 | Number 1, Volume 30

Prenatal carnitine supplementation may help prevent ASD caused by TMLHE gene mutation

One gene implicated as a contributor to autism—a mutated variant of the TMLHE gene—makes it impossible for cells to manufacture carnitine. New research suggests that for children with this gene, prenatal carnitine supplementation may help prevent autism. 

Zhigang Xie and colleagues have refined a technology that allows them to mark, follow, and analyze individual neural stem cells in a developing brain. Studying embryonic mouse brains, they were able to determine that neural stem cells unable to produce carnitine because of a defective TMLHE gene do not function properly. 

Normally when neural stem cells divide, they produce two “daughter” cells; one remains a neural stem cell, while the other differentiates. Neural stem cells that are deficient in carnitine frequently produce two differentiated cells instead, failing to resupply the brain with needed neural stem cells. 

To see if providing cells with carnitine could correct this abnormality, the researchers incubated fetal forebrain tissue in a medium with or without carnitine. They found that in the presence of carnitine, the cells functioned normally. 

The researchers note that the TMLHE gene is located on the X chromosome. Because males have only one X chromosome, while females have two (the second gene could compensate for the mutated one), male children are at greater risk for TMLHE-associated autism. 

In addition to manufacturing carnitine, the body obtains it from food. Red meat is very high in carnitine and whole milk is a good source, while vegetables are very low in this nutrient. The researchers speculate that mothers who eat few carnitine-rich foods during pregnancy may put children with the TMLHE gene variant at greater risk for developing autism. 

They conclude, “We suggest that genetic screening of prospective parents for TMLHE mutations, coupled with the inclusion of carnitine as a dietary supplement upon initial diagnosis of pregnancy, promises mental health benefits for newborns otherwise at significant risk for developmental brain disorders.” 


Citations

“Inborn errors of long-chain fatty acid β-oxidation link neural stem cell self-renewal to autism,” Zhigang Xie, Albert Jones, Jude T. Deeney, Seong Kwon Hur, and Vytas A. Bankaitis, Cell Reports, February 9, 2016 (online). Address: Zhigang Xie, [email protected]

—and— 

“Research hints at a nutritional strategy for reducing autism risk,” Christina Sumners, Vital Record, Texas A&M Health Science Center, January 28, 2016.