TRAX study ParticipantFragile X carriers are individuals with the FMR1 premutation, who are at risk of developing a neurodegenerative condition called fragile X-associated tremor/ ataxia syndrome (FXTAS) in later life. FXTAS symptoms include tremor, balance problems, cognitive changes, and a range of other neurological problems.

This study, co-directed by Dr. David Hessl and Dr. Susan Rivera,  aims to discover genetic, brain and cognitive factors that may precede or occur with the onset of FXTAS in adult male fragile X carriers. This is the first longitudinal study of this population. We study intellectual function, motor function, executive function, memory, dexterity, and balance, as well as learn about participants’ psychological health. The brain health portion of our study is completed through magnetic resonance imaging (MRI). Information gathered from these scans includes size, shape, and integrity of the brain and its structures.

We know that many of our participants and their family members have questions about the premutation, especially how to identify early signs of neurodegeneration and most importantly how to treat or prevent FXTAS. While this is not a treatment study, it will provide extremely valuable information about the natural course of aging in these carriers that will inform treatment studies, and we are working hard, with Dr. Randi Hagerman and others, to identify the most promising interventions to investigate. Our study will also help to develop and validate clinical or neuroimaging methods that could be used to track effectiveness of these interventions. Here is list of the scientific publications that were made possible by this study (PDF).

We continue to recruit new participants, and also to bring participants back for follow up visits, and we have enjoyed getting to know them over time. We have learned a great deal about the structure of white matter in the brain, aspects of social cognition, anxiety, and age-related patterns of changes in brain structure. We look forward to exploring the longitudinal data over the course of this study.

If you or someone you know would be interested to participate in this study, please contact Glenda M Espinal at or by phone at 916-703-0470.