Abstracts

Rationale: The high incidence of epilepsy in subjects with chromosomal abnormalities and the presence of specific microdeletion syndromes with major epileptic features (i.e., Angelman syndrome, Wolf-Hirschhorn syndrome) suggest that genomic rearrangements may be more common than currently thought in human epilepsy. Recent data report the identification by array-comparative genomic hybridization (a-CGH) of new microrearrangements in patients with epilepsy and mental retardation. Array-CGH is a genetic technique able to screen the whole genome with high resolution detecting abnormalities not visible with standard karyotype. We investigated the occurrence of chromosomal microrearrangements in patients with epilepsy and mental retardation by array-CGH. Methods: Patients with the following criteria were included: partial or generalized epilepsy; slight to moderate mental retardation; normal karyotype. The occurrence of minor dysmorphisms and/or minor MRI structural changes were not exclusion criteria. Array-CGH was performed using the Agilent Human Genome CGH Microarray Kit 44B (Agilent, Santa Clara). Results: 94 patient (57 male and 37 females) with median age 18.72 years were collected. CGH analysis identified a chromosomal microrearrangement in 13 patients (12.22 %).[ 2 pt with 22q del; 1q del; 15q dup; 10p del; 15q del; 6q del; 19q del; Xp dup; t (7,14) q ; 8p inv dup del ; 9p del; Xq ]. Genetic study in the parents revealed that most rearrangements occurred de novo. Conclusions: Array-CGH is a valid diagnostic tool to detect microrearrangements in patients with “cryptogenetic” epilepsy and mental retardation and dysmorphisms. Further studies will clarify whether array-CGH should be routinely performed in patients with normal standard cytogenetic study.