P08.5 Intractable myoclonic epilepsy, mental retardation and dysmorphic features in a boy with chromosomal aberration: 46XY. ish der(15)t(X;15)(p22.; q26.3)dn

Abstract

Background: Mental retardation affects 2-3% of general population and genetic cause can be detected in around 5% of patients. Many of these patients also suffer from epilepsy. Aim of the study: We present 13 years old patient with de novo chromosomal aberation characterized by addition of Xp chromosome (partial trisomy) to terminal part of 15q chromosome associated with intractable myoclonic epilepsy, mental retardation and dysmorphic features. Methods: The boy is third child of healthy parents and has two healthy siblings. At the age of 6 months psychomotor retardation was noticed. He revealed numerous dysmorphic features: down-slanted palpebral fissures, hypertelorism, micrognatia, dysmorphic ears, clubbing fingers and genital malformations. At the age of 10 he developed intractable myoclonic-astatic epilepsy that resulted in frequent falls and injuries. At present he is moderately mentally retarded, has clumsy gait and his somatic development follows 5th percentile for height and weight, while he is normocephalic. Results: EEG recordings showed slower cerebral activity with diffuse paroxysmal discharges of high-voltage polyspike-wave complexes. MRI showed moderate dilation of lateral ventricles, small hyperintensive areas in peritrigonal white matter and depletion of white matter of dorsal corpus callosum. Standard karyotype revealed an excess of the Xp material attached to the terminal part of the 15q. FISH analysis performed by SHOX probe confirmed the excess of genetic material of Xp on 15q. Conclusion: Our presentation is additional contribution to genetic cause of mental retardation, dysmorphic features and intractable epilepsy, to our knowledge not described by now.