Original article Electro-clinical phenotypes of chromosome disorders associated with epilepsy in the absence of dysmorphism q Stewart Macleod a , Arup Mallik b , John L. Tolmie c , John B.P Stephenson a , Mary E. O’Regan a , Sameer M. Zuberi a, * a Fraser of Allander Neurosciences Unit, Royal Hospital for Sick Children, Yorkhill, Glasgow, UK b Regional Clinical Neurophysiology Department, Southern General Hospital, Glasgow, UK c Duncan Guthrie Institute of Medical Genetics, Royal Hospital for Sick Children, Glasgow, UK Received 14 July 2003; accepted 1 October 2003 Abstract Chromosome imbalances are associated with epilepsy but electro-clinical phenotypes are lacking for all but the best-known syndromes. Scanty information is contained in older case reports published in genetics journals that describe children with severe patterns of malformation and dysmorphism. From a larger series of children with chromosome abnormalities and epilepsy, we identified 10 patients with associated dysmorphism without malformation. Electro-clinical features are described for each patient. We found that these patients are at greater risk of delayed diagnosis, particularly when there are no learning difficulties at the onset of epilepsy, as in ring chromosome 20 syndrome. Chromosome studies should be ordered on all children with learning difficulties and epilepsy, and on children with atypical non-lesional epilepsy, even in the absence of learning difficulties or dysmorphism. q 2004 Elsevier B.V. All rights reserved. Keywords: Chromosome; Epilepsy; Dysmorphism 1. Introduction Epilepsy is a complication of many chromosomal abnormality syndromes [1,2]. However, there are only a small number of chromosome abnormalities that have epilepsy as a consistent feature. These include the Miller-Dieker syndrome del(17) (pter ! p13) [3,4], Angelman syndrome del(15)(q11 ! q13)mat [5,6], and ring chromosome 20 syndrome [7,8]. Electro-clinical descriptions of the epilepsies associated with these conditions and other common chromosome abnormalities such as trisomy 21[8–10] are thoroughly described. However, information about epilepsy in other chromosome disorders is predominantly found in genetics journals and the descriptions of the epilepsy phenotype are often very sparse. If more detailed descriptions of epilepsy phenotypes associated with chromosome disorders were available, this would permit recognition of characteristic patterns of clinical presentation and EEG features and facilitate diagnosis. Data on seizure semiology would help to tailor appropriate treatment regimes and may be used to give patients and carers information on prognosis. Finally, electro-clinical descriptions allied to more sophisticated cytogenetic and molecular techniques may give clues in the search for genes associated with epilepsy. Ieshima et al. found that 6% of patients with learning difficulties and epilepsy had a chromosome abnormality [11]. This figure rises to 50% in patients with major congenital malformations yet chromosome studies are often omitted from the work-up of children with learning difficulties and epilepsy, particularly if the child is not dysmorphic, or if the child develops cognitive problems after the onset of epilepsy. We report a series of non-dysmorphic patients with epilepsy and a chromosome abnormality taken from a larger series of children with chromosome disorders and epilepsy. Brain & Development 27 (2005) 118–124 www.elsevier.com/locate/braindev 0387-7604/$ - see front matter q 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.braindev.2003.10.006 q The paper is based on the lecture given at the 6th annual meeting of the Infantile Seizure Society, Tokyo, March 15–16, 2003. * Corresponding author. Fax: þ 44-141-201-0671. E-mail address: sameer.zuberi@yorkhill.scot.nhs (S.M. Zuberi).