title: Cortical damage in brains of patients with adult-form of myotonic dystrophy type 1 and no or minimal MRI abnormalities.
abstract: OBJECTIVE
  To evaluate, by using quantitative MRI metrics, subtle cortical changes in brains of patients with the adult form of myotonic dystrophy type I (DM1) who showed no or minimal abnormalities on MRI.
  
  
  BACKGROUND
  DM1 is an autosomal dominant multisystem disorder caused by the expansion of CTG repeats in the myotonic dystrophy-protein kinase gene. Mild to severe involvement of the CNS can be part of the clinical features of the disease. Several MRI studies have demonstrated that both focal white matter (WM) lesions and diffuse grey matter atrophy can be found in the brains of DM1 patients. However, whether these two processes are related or may occur independently is not clear.
  
  
  METHODS
  Ten genetically-proven DM1 patients who showed no or minimal abnormalities on MRI underwent a new brain MRI examination to obtain computerized measures of total and regional brain volumes normalized to head size and regional measurements of the magnetization transfer ratio (MTr).
  
  
  RESULTS
  Normalized brain volumes (NBV) were significantly (p < 0.0001) lower in DM1 subjects than in a group of age- and sex-matched normal controls. Normalized cortical volumes (NCV) also were lower (p = 0.003) in DM1 subjects than in normal controls, whereas normalized WM volumes were not different between the two groups (p = 0.3). In agreement with this, values of MTr in the neocortex (cortical-MTr) were significantly (p = 0.006) lower in DM1 patients than in normal controls and this difference was not found in the WM tissue (p = 0.8).
  
  
  CONCLUSIONS
  Neocortical damage seems to be evident in the absence of visible WM lesions suggesting that a neocortical pathology, unrelated to WM lesion formation, occurs in DM1 brains.
authors.affiliation: Neurology & Neurometabolic Unit, Dept Neurological and Behavioral Sciences, University of Siena, Viale Bracci 2, 53100, Siena, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Giorgio
authors.forename: Maria T
authors.initials: MT
authors.lastname: Dotti
authors.forename: Marco
authors.initials: M
authors.lastname: Battaglini
authors.forename: Silvia
authors.initials: S
authors.lastname: Marino
authors.forename: Marzia
authors.initials: M
authors.lastname: Mortilla
authors.forename: Maria L
authors.initials: ML
authors.lastname: Stromillo
authors.forename: Placido
authors.initials: P
authors.lastname: Bramanti
authors.forename: Alfredo
authors.initials: A
authors.lastname: Orrico
authors.forename: Antonio
authors.initials: A
authors.lastname: Federico
authors.forename: Nicola
authors.initials: N
authors.lastname: De Stefano
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000473:pathology*