À propos du GNT

Fragile X syndrome (FXS), also known as Martin-Bell syndrome, is a genetic condition and the most common inherited cause of intellectual disability. It is also frequently associated with autism spectrum disorder. FXS can affect cognitive, behavioral, sensory, and social functioning and may involve a range of physical and neuropsychiatric conditions. The syndrome is associated with alterations in brain development, synaptic functioning, and neurological processes that have prompted questions about possible vulnerability to neurodegenerative disorders later in life.

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An important distinction exists between fragile X syndrome (FXS) and fragile X-associated tremor/ataxia syndrome (FXTAS). FXS typically results from a full mutation of the FMR1 gene and is characterized by developmental and cognitive differences beginning in childhood. In contrast, FXTAS occurs in some individuals who carry an FMR1 premutation and is a recognized late-onset neurodegenerative disorder. FXTAS may involve progressive tremor, difficulties with balance and coordination, memory impairment, executive dysfunction, and behavioral changes. In some individuals, cognitive deterioration progresses to dementia.

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The relationship between fragile X conditions and dementia remains incompletely understood. Although concerns have been raised about possible neurodegenerative vulnerability among aging adults with FXS, current evidence is insufficient to establish that individuals with the full FMR1 mutation have an independently increased risk of Alzheimer's disease or other dementias. By comparison, progressive cognitive decline and dementia are recognized clinical features of FXTAS in some premutation carriers, although the underlying disease processes differ from those typically associated with Alzheimer's disease.

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These distinctions have important implications for clinical assessment and care planning. Recognizing acquired changes in cognition, behavior, mobility, and everyday functioning requires careful consideration of an individual's lifelong abilities and neurological history. Further longitudinal research is needed to clarify dementia risk among older adults with FXS and intellectual disability, improve the identification of neurodegenerative changes in individuals with FXTAS, and guide appropriate diagnostic evaluation, treatment, and supportive care.

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