title: Kleefstra syndrome in Hungarian patients: additional symptoms besides the classic phenotype.
abstract: BACKGROUND
  Kleefstra syndrome is a rare genetic disorder, with core phenotypic features encompassing developmental delay/intellectual disability, characteristic facial features - brachy(micro)cephaly, unusual shaped eyebrows, flat face with hypertelorism, short nose with anteverted nostrils, thickened lower lip, carpmouth with macroglossia - and childhood hypotonia. Some additional symptoms are observed in different percentage of the patients. Epilepsy is common symptom as well. The underlying cause of the syndrome is a submicroscopic deletion in the chromosomal region 9q34.3 or disruption of the euchromatin histone methyl transferase 1.
  
  
  METHODS
  We describe two Hungarian Kleefstra syndrome patients, one with the classic phenotype of the syndrome, the diagnosis was confirmed by subtelomeric FISH. Meanwhile in our second patient beside the classic phenotype a new symptom - abnormal antiepileptic drug metabolic response - could be observed. Subtelomere FISH confirmed the 9q34.3 terminal deletion. Because of the abnormal drug metabolism in our second patient, we performed array CGH analysis as well searching for other rearrangements. Array CGH analysis indicated a large - 1.211 Mb -, deletion only in the 9q subtelomeric region with breakpoints ch9:139,641,471-140,852,911.
  
  
  CONCLUSIONS
  This is the first report on Kleefstra syndrome in patients describing a classical and a complex phenotype involving altered drug metabolism.
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary ; Szentagothai Research Center, University of Pecs, Ifjusag 20, H-7624 Pecs, Hungary.
authors.forename: Kinga
authors.initials: K
authors.lastname: Hadzsiev
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary ; Szentagothai Research Center, University of Pecs, Ifjusag 20, H-7624 Pecs, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Komlosi
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary ; Szentagothai Research Center, University of Pecs, Ifjusag 20, H-7624 Pecs, Hungary.
authors.forename: Marta
authors.initials: M
authors.lastname: Czako
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary ; Szentagothai Research Center, University of Pecs, Ifjusag 20, H-7624 Pecs, Hungary.
authors.forename: Balazs
authors.initials: B
authors.lastname: Duga
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary ; Szentagothai Research Center, University of Pecs, Ifjusag 20, H-7624 Pecs, Hungary.
authors.forename: Renata
authors.initials: R
authors.lastname: Szalai
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary.
authors.forename: Andras
authors.initials: A
authors.lastname: Szabo
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary.
authors.forename: Etelka
authors.initials: E
authors.lastname: Postyeni
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary.
authors.forename: Titanilla
authors.initials: T
authors.lastname: Szabo
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary ; Szentagothai Research Center, University of Pecs, Ifjusag 20, H-7624 Pecs, Hungary.
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Kosztolanyi
authors.affiliation: Department of Medical Genetics, Clinical Center, University of Pecs, Szigeti 12, H-7624 Pecs, Hungary ; Szentagothai Research Center, University of Pecs, Ifjusag 20, H-7624 Pecs, Hungary.
authors.forename: Bela
authors.initials: B
authors.lastname: Melegh
keywords: 9q subtelomeric deletion syndrome; Drug metabolism; Epilepsy; Kleefstra syndrome