Update on several/certain adult-onset genetic leukoencephalopathies: clinical signs and molecular confirmation

Adult-onset leukoencephalopathies are clinically and pathologically heterogeneous diseases, characterized by overlapping clinical and neuroradiological features and a difficult diagnostic process. Nevertheless, knowledge of the metabolic and genetic basis of leukoencephalopathies is constantly increasing. This article provides an overview of currently known leukoencephalopathies in adulthood, emphasizing, in addition to the classical forms, their atypical clinical presentations. In particular, we review the clinical spectrum and the molecular pathogenesis of certain adult-onset leukoencephalopathies, including cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), cerebroretinal microangiopathy with calcifications and cysts (CRMCC), hereditary diffuse leukoencephalopathy with spheroids (HDLS), fragile X-associated tremor/ataxia syndrome (FXTAS), vanishing white matter disease (VWM), autosomal dominant leukodystrophy due to lamin B1 duplication (ADLD), and vascular leukoencephalopathy mapping to chromosome 20q13.