Table 1.

Fragile X-associated tremor/ataxia syndrome FXTAS diagnostic criteria

FXTAS category: a	Exam and degree	Observation
Definite:	Radiological
One clinical major and one of the following:	Major	MRI white matter lesions in middle cerebellar peduncle and/or brain stem
• one radiological major criterion	Minor	MRI white matter lesions in cerebral white matter
• presence of intranuclear inclusion	Minor	Moderate to severe generalized atrophy
	Clinical
Probable:	Major	Action tremor
One of the following:	Major	Cerebellar gait ataxia
	Minor	Parkinsonism
• two clinical major criteria	Minor	Moderate to severe short-term memory deficiency
• one radiological major criterion and one clinical minor criterion	Minor	Executive function deficit
	Pathological
	Major	Classic FXTAS CNS intranuclear inclusions
Possible:
Both of the following:
• one clinical major criterion
• one radiological minor criterion

^aFor all categories, must have FMR1 premutation. CNS, central nervous system; MRI, magnetic resonance imaging.