Objectives:: Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neuropsychiatric degenerative disorder that occurs predominantly in male FMR1 premutation carriers. Recently, a broader FXTAS spectrum that, besides the core features of tremor and gait ataxia, also includes neuropsychiatric symptoms and neuropathy as further clinically relevant symptoms has been described among females. Herein 2 fragile X syndrome families with a mother-daughter FXTAS transmission are described in detail in order to shed more light on the female FXTAS phenotype. Methods:: Molecular characterization included CGG repeat length, X-chromosome inactivation pattern determination, as well as FMR1 mRNA and FMRP levels quantification. Neuroradiologic examination was performed by 3-T MRI. Neuropsychological assessment included global cognitive, attention, and executive prefrontal functions, verbal fluencies, verbal memory, and visuospatial perception. Results:: Molecular, neurologic, neuropsychiatric, psychological, cognitive, and neuroradiologic features description of 2 fragile X syndrome families with a mother-daughter FXTAS transmission in which dementia is present in both mothers. Conclusions:: Although it is not yet clear to what extent FXTAS shortens lifespan, our findings show that FXTAS progresses from mild tremor and/or ataxia to disabling motor and cognitive impairment, compromising the patients' quality of life. Furthermore, our results show that FXTAS in women can also develop as a multisystem neurodegenerative disorder with central and peripheral nervous system involvement, and both motor and mental disturbances. Copyright © 2010 by AAN Enterprises, Inc.