title: Analyses of Gonadoblastoma Y (GBY)-locus and of Y centromere in Turner syndrome patients.
abstract: BACKGROUND
  Mosaicism with cytogenetically visible Y chromosome is found in 5-6% of Turner Syndrome (TS) patients. Additionally, occult Y-chromosome derived material is increasingly found in patients with monosomy X when using more sensitive molecular techniques. These TS patients are at risk of developing gonadoblastomas when the Y genes presumed to be involved in gonadoblastoma development (Gonadoblastoma-Y-locus; GBY) are present.
  
  
  OBJECTIVE
  To find occult Y-chromosome material in TS patients and to correlate the patient's phenotype to Y-chromosome material.
  
  
  METHODS
  We studied 60 TS-patients for presence of the Y chromosome with focus on the Gonadoblastoma Y-locus and its extension in Yp and Yq using sensitive Y centromere and Y gene deletion PCR assays. In addition, we evaluated their individual clinical and auxological characteristics.
  
  
  RESULTS
  We identified presence of the GBY-locus in 7 patients (11.7%) including 4 patients without evidence for a Y chromosome in their preceding standard karyotype analyses. Clinical and auxological characteristics were similar in GBY-positive and GBY-negative patients.
  
  
  CONCLUSIONS
  Presence of the GBY locus in Turner patients with no indication of the Y chromosome in standard cytogenetic chromosome analysis can be revealed by sensitive molecular PCR assays screening for presence of the Y centromere and the GBY-candidate-genes in proximal Yp11 and Yq11, respectively.
authors.affiliation: Division of Paediatric Endocrinology, Children's Hospital, University of Heidelberg.
authors.forename: S
authors.initials: S
authors.lastname: Knauer-Fischer
authors.affiliation: Division of Reproductive Genetics, Women's Hospital, University of Heidelberg.
authors.forename: B
authors.initials: B
authors.lastname: Besikoglu
authors.affiliation: Division of Paediatric Endocrinology, Children's Hospital, University of Heidelberg.
authors.forename: I
authors.initials: I
authors.lastname: Inta
authors.affiliation: Division of Paediatric Endocrinology, Children's Hospital, University of Heidelberg.
authors.forename: C
authors.initials: C
authors.lastname: Kneppo
authors.affiliation: Division of Reproductive Genetics, Women's Hospital, University of Heidelberg.
authors.forename: P H
authors.initials: PH
authors.lastname: Vogt
authors.affiliation: Division of Paediatric Endocrinology, Children's Hospital, University of Heidelberg.
authors.forename: M
authors.initials: M
authors.lastname: Bettendorf
mesh_terms: D000293:Adolescent; D002503:Centromere / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D041322:Chromosomes, Human, Y / Q000235:genetics*; D056426:Genetic Loci; D018238:Gonadoblastoma / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D009634:Noonan Syndrome / Q000235:genetics*