Date of Completion


Embargo Period



Rachel O'Neill; Barbara Mellone

Field of Study

Genetics and Genomics


Master of Science

Open Access

Open Access


Genomic imprinting is an epigenetic phenomenon resulting in differential gene expression based on parental origin. Recently, transketolase-like 1 (TKTL1) has been identified as an X-linked imprinted gene. TKTL1 functions in the nonoxidative branch of the pentose phosphate pathway (PPP), which maintains glutathione in a reduced state through the generation of NADPH. Previous studies on transaldolase, the other critical enzyme in the nonoxidative branch of the PPP, suggest that TKTL1 may affect the cell’s ability to reduce glutathione. This study provides evidence that TKTL1 overexpression inhibits glutathione reduction. Intriguingly, aberrant glutathione levels are associated with autism. Additionally, studies involving Turner syndrome females found that differences in social behavior could distinguish females expressing the maternal X chromosome from those expressing the paternal X chromosome. This led researchers to hypothesize the influence of an X-linked imprinted gene in autism. Accordingly, this study compared TKTL1 expression levels in autistic patients versus their unaffected siblings. The results suggest that further studies are required.

Major Advisor

Michael O'Neill