Glyoxalase I polymorphism rs2736654 causing the Ala111Glu substitution modulates enzyme activity—implications for autism

Lay Abstract Autism is a complex developmental disability characterized by abnormalities in spoken language, socialization and repetitive behaviors. In recent years, an increase in the number of autism cases worldwide has been reported. Researchers have found evidence that autism is caused by multiple genetic factors, and a number of potential risk genes have been identified. Earlier we have found an increased frequency in subject with autism of a form of the enzyme glyoxalase I (Glo1) that has glutamic acid at position 111. By using lymphoblastoid and neuronal cells in culture, we now present evidence that this form of Glo1 is reduced in function, and consequently accumulates a toxic metabolite called methylglyoxal (MG). MG can form conjugates with cellular proteins, thereby compromising their function. We propose that an increase in conjugated proteins causes over-expression of receptors that bind these altered proteins, which in turn can initiate cascades of potentially harmful events. These studies suggest that in a subset of individuals with autism, the occurrence of the Glo1 polymorphism may precipitate changes in cellular structure and function that support risk for autism.