Chromosome abnormalities and epilepsy.

Abstract

Chromosome abnormalities are often associated with central nervous system (CNS) malformations and with other neurologic dysfunctions. In particular, patients with chromosomal abnormalities can have mental retardation (MR) and have a higher risk for seizures than that found in the general population (1). Genetic tools such as karyotyping, high-resolution chromosome banding, fluorescent in situ hybridization (FISH), and other molecular genetics techniques have increased the number of chromosome abnormalities detected in subjects with MR or seizures. However, the majority of studies and reports published have usually considered sporadic cases or very small groups of patients with chromosome abnormalities. Furthermore, the characteristics of seizures and EEGs have been described in detail on very few occasions, to define the electroclinical phenotype, and eventually to classify the epilepsy. In recent years, a few identified chromosome abnormality syndromes seem to show a particular clinical and EEG picture; some of them are relatively common, such as Angelman’s syndrome, the fragile-X (fra-X) syndrome, the Miller‐Dieker syndrome; and others are more rare, such as trisomy 12p syndrome, the Wolf‐ Hirschhorn syndrome, and ring 20 syndrome. We review some clinical and neurophysiologic aspects of these syndromes that can support the neurologist in choosing the genetic analysis to be carried out, and help to identify specific genes influencing epileptogenesis. ANGELMAN’S SYNDROME