Ring 21 chromosome presenting with epilepsy and intellectual disability: Clinical report and review of the literature.

摘要

Several chromosomal abnormalities lead to anatomic alteration of the central nervous system, and most of them are accompanied by intellectual disability. Among patients with epilepsy and intellectual disability, about 6% have chromosomal abnormalities [Singh et al., 2002]. The majority of chromosome aberrations can be associated with a variety of epilepsy phenotypes and seizure types, but there are certain aberrations which show specific seizure and electroenceph-alographic (EEG) patterns. Chromosomal aberrations associated with epilepsy are mainly characterized by chromosome breaks and subsequent loss of genetic material. The more frequently reported deletions involve chromosomes 1 and 4 (del Ip36, del 4pl6.3) [Battaglia and Guerrini, 2005]. Ring chromosomes could also be the cause of different epileptic phenotypes. Ring chromosomes 14, 17, and 20 are related to a well-defined epileptic electro-clinical picture [Singh et al., 2002]. Single cases have been published with ring chromosome 4 [Soysal et al., 2009], 6 [Kara et al., 2008], 9 [Lanzi et al., 1996], 18 [Nakayama et al., 1997], and 19 [Shahwan et al., 2004] associated with epilepsy.