Myotonic dystrophy type 1 associated with white matter hyperintense lesions: clinic, imaging, and genetic analysis

Myotonic dystrophy (DM) is a chronic, slowly progressing, highly variable, inherited multisystemic disease, which includes two main types: DM type 1 (DM1) and DM type 2 (DM2). Both DM1 and DM2 are autosomal dominantly inherited disorder. DM1, also called Steinert disease, is characterized by myotonia, muscle weakness, muscular dystrophy, endocrinopathy, cataract, cardiac conduction defect, central nervous system (CNS) dysfunction, and so on. The symptoms of CNS abnormalities mainly include impaired motor function, cognitive impairment, fatigue, and depression. The magnetic resonance images (MRI) of the brain may show brain atrophy and (or) white matter hyperintense lesions (WMHLs) on T2 or fluid-attenuated inversion recovery.[1] DM1 is caused by an expanded (CTG) n repeat (from 37 to several thousands) within the noncoding 3’untranslated region of the myotonic dystrophy protein kinase (DMPK) gene on chromosome 19q35. DM2, also called proximal myotonic myopathy, is rarer than DM1 and generally manifests with milder signs and symptoms, and is caused by an expanded CCTG repeat (from 75 to 11,000 repeats) in the first intron of the zinc finger protein 9 (ZNF9) gene on chromosome 3q21. Till now, there are few reports of DM with WMHLs in China. Here, we reported one case of DM1 with WMHLs, characterized by bilateral anterior temporal WMHLs (ATWMHLs).