Résumé en anglais
 
Steinert's Myotonic Dystrophy (DM) is a neuromuscular disease of variable severity with a clinical phenomenon of anticipation due to an unstable mutation. Classically, there are three clinical forms, a mild late form with few symptoms which can be limited to a cataract, a classical adult form with myotonie and muscle weakness with onset between 20 and 30 years of age and a serious congenital form (CDM). A fourth form can also be distinguished; this is a childhood form with onset later than one year and less severe than CDM.
The cognitive problems of this disorder are variable: from almost constant and severe mental retardation in the congenital form to more specific cognitive difficulties in the classical adult form, which have been the subject of numerous publications. In the juvenile form, learning difficulties are very frequent and one of the principal clinical features. Nevertheless, the distinction between neonatal and childhood DM is not always clear, and in both forms, a school retardation is constantly present. The goals of this research project are to better understand the cognitive dysfunction which affects chiidren with this form of DM, and to observe whether the same features can be found in the classical adult form (in this case, could we speak of a continuum?) and to determine a specific cognitive profile, notably at the level of executive and mnemonic functions (is there one homogeneous group, or subgroups with characteristic dysfunctions depending on the carrier parent and the extent of triplet expansion?).
We therefore propose to perform a detailed neuropsychological study of 40 chiidren with the juvenile form of this disorder, separating the children into groups of 20 based on whether the mode of transmission is paternai or maternai.