title: Relevance of corpus callosum splenium versus middle cerebellar peduncle hyperintensity for FXTAS diagnosis in clinical practice.
abstract: Fragile X-associated tremor ataxia syndrome (FXTAS) is caused by FMR1 premutation. The features include ataxia, action tremor and middle cerebellar peduncle (MCP) hyperintensity, the latter being the only major radiological criterion in the diagnosis of definite FXTAS until very recently. The importance of corpus callosum splenium (CCS) hyperintensity was recently reported and this sign is now considered as an additional major radiological diagnostic criterion in the diagnosis of FXTAS. However, little is known about its relevance for the diagnosis of FXTAS in clinical practice. We report a practical justification of the relevance of CCS hyperintensity in parallel with MCP hyperintensity for the diagnosis of FXTAS. Clinical and radiological study of 22 FMR1 premutation carriers with neurological signs that may be encountered in FXTAS compared to series of patients with essential tremor, multiple system atrophy of cerebellar type, Parkinson's disease, Alzheimer's disease and stroke. Among the 22 patients with FMR1 premutation [17 men, 5 women; mean age, 63 ± 7.5 (46-84)], 14 were diagnosed with definite FXTAS with the initial criteria. Considering CCS hyperintensity as a new major radiological criterion permitted the diagnosis of definite FXTAS in 3 additional patients. Overall CCS proved as frequent as MCP hyperintensity (64 versus 64 %), while 23 % of patients had CCS but not MCP hyperintensity, 14 % of patients had CCS hyperintensity but neither MCP, nor brainstem hyperintensity. In contrast with CCS hyperintensity, MCP hyperintensity proved less frequent in women than in men. CCS and MCP hyperintensity were more frequent in FXTAS than in the other neurodegenerative disorders. The combination of CCS and MCP hyperintensity was specific of FXTAS. We confirmed the relevance of CCS hyperintensity in FXTAS and we clarified its interest compared to MCP hyperintensity. Our results support the inclusion of CCS hyperintensity in the diagnostic criteria as a new major radiological criterion.
authors.affiliation: Département de Neurologie, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 1 Avenue Molière, 67098, Strasbourg Cedex, France.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Renaud
authors.forename: Julien
authors.initials: J
authors.lastname: Perriard
authors.forename: Sarah
authors.initials: S
authors.lastname: Coudray
authors.forename: Mathieu
authors.initials: M
authors.lastname: Sévin-Allouet
authors.forename: Christophe
authors.initials: C
authors.lastname: Marcel
authors.forename: Wassilios G
authors.initials: WG
authors.lastname: Meissner
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Chanson
authors.forename: Nicolas
authors.initials: N
authors.lastname: Collongues
authors.forename: Nathalie
authors.initials: N
authors.lastname: Philippi
authors.forename: Odile
authors.initials: O
authors.lastname: Gebus
authors.forename: Véronique
authors.initials: V
authors.lastname: Quenardelle
authors.forename: Anna
authors.initials: A
authors.lastname: Castrioto
authors.forename: Paul
authors.initials: P
authors.lastname: Krack
authors.forename: Karine
authors.initials: K
authors.lastname: N'Guyen
authors.forename: François
authors.initials: F
authors.lastname: Lefebvre
authors.forename: Andoni
authors.initials: A
authors.lastname: Echaniz-Laguna
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Azulay
authors.forename: Nicolas
authors.initials: N
authors.lastname: Meyer
authors.forename: Pierre
authors.initials: P
authors.lastname: Labauge
authors.forename: Christine
authors.initials: C
authors.lastname: Tranchant
authors.forename: Mathieu
authors.initials: M
authors.lastname: Anheim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001259:Ataxia / Q000175:diagnosis*; D003337:Corpus Callosum / Q000473:pathology*; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics; D005600:Fragile X Syndrome / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D065837:Middle Cerebellar Peduncle / Q000473:pathology*; D014202:Tremor / Q000175:diagnosis*
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; C497683:FMR1 protein, human