title: A de novo atypical ring sSMC(22) characterized by array CGH in a boy with cat-eye syndrome.
abstract: BACKGROUND
  Microduplications 22q11 have been characterized as a genomic duplication syndrome mediated by nonallelic homologous recombination between region-specific low-copy repeats. Here we report on a 19 years old boy with intellectual disability having an unexpected structurally complex ring small supernumerary marker chromosome (sSMC) originated from a larger trisomy and a smaller tetrasomy of proximal 22q11 harboring additional copies of cat eye syndrome critical regions genes.
  
  
  RESULTS
  PRINCIPAL CLINICAL FEATURES WERE: anorectal and urogenital malformations, total anomalous pulmonary venous return with secundum ASD, hearing defect, preauricular pits, seizure and eczema. The proband also presented some rare or so far not reported clinical findings such as hyperinsulinaemia, severe immunodeficiency and grave cognitive deficits. Chromosome analysis revealed a mosaic karyotype with the presence of a small ring-like marker in 60% of cells. Array CGH detected approximately an 1,2 Mb single and a 0,2 Mb double copy gain of the proximal long arm of chromosome 22. The 1,3 Mb intervening region of chromosome 22 from centromere to the breakpoints showed no copy alteration. The karyotype of the patient was defined as 47,XY,+mar[60]/46,XY[40].ish idic r(22)(q11.1.q11.21) × 4.arr 22q11(17,435, 645-18,656,678) × 3,(17,598,642-17,799,783) × 4 dn.
  
  
  CONCLUSIONS
  The present report is the first one with a detailed description of clinical presentation in a patient carrying an atypical size ring sSMC (22) analyzed by array CGH. The specialty of the finding is emphasized by the fact that although the patient had a mosaic sSMC and the amplified region was smaller than in typical cat eye syndrome cases, the clinical presentation was severe.
authors: 2nd Department of Paediatrics, Semmelweis University, Tűzoltó utca 7-9, Budapest 1094, Hungary.
authors: Irén
authors: I
authors: Haltrich
authors: Department of Molecular Genetics and Diagnostics, National Institute of Environmental Health, Budapest, Hungary.
authors: Henriett
authors: H
authors: Pikó
authors: 2nd Department of Paediatrics, Semmelweis University, Tűzoltó utca 7-9, Budapest 1094, Hungary.
authors: Eszter
authors: E
authors: Kiss
authors: 2nd Department of Paediatrics, Semmelweis University, Tűzoltó utca 7-9, Budapest 1094, Hungary.
authors: Zsuzsa
authors: Z
authors: Tóth
authors: Department of Molecular Genetics and Diagnostics, National Institute of Environmental Health, Budapest, Hungary.
authors: Veronika
authors: V
authors: Karcagi
authors: 2nd Department of Paediatrics, Semmelweis University, Tűzoltó utca 7-9, Budapest 1094, Hungary.
authors: György
authors: G
authors: Fekete
keywords: Cat eye syndrome; Microarray; Small supernumerary marker chromosome; ring(22); sSMC