Cytogenetic and molecular characterization of two isodicentric Y chromosomes

✍ Scribed by Stankiewicz, Pawe? ;H�lias-Rodzewicz, Zofia ;Jakub�w-Durska, Krystyna ;Bocian, Ewa ;Obersztyn, Ewa ;Rappold, Gudrun A. ;Mazurczak, Tadeusz

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 258 KB
• Volume: 101
• Category: Article
• ISSN: 0148-7299
• DOI: 10.1002/ajmg.1304

✦ Synopsis

We report the results of detailed molecularcytogenetic studies of two isodicentric Y [idic(Y)] chromosomes identi®ed in patients with complex mosaic karyotypes. We used ¯uorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) to determine the structure and genetic content of the abnormal chromosomes. In the ®rst patient, classical cytogenetics and FISH analysis with Y chromosome-speci®c probes showed in peripheral blood lymphocytes a karyotype with 4 cell lines: 45,X[128]/46,X, idic(Y)(p11.32)[65]/47,XY,idic(Y)(p11.32)[2]/ 47,X,2idic(Y)(p11.32) [1]. No Y chromosome material was found in the removed gonads. For precise characterization of the Yp breakpoint, FISH and ®berFISH analysis, using a telomeric probe and a panel of cosmid probes from the pseudoautosomal region PAR1, was performed. The results showed that the breakpoint maps $1,000 Kb from Ypter. The second idic(Y) chromosome was found in a boy with mild mental retardation, craniofacial anomalies, and the karyotype in lymphocytes 47,X,idic(Y)(q11.23), i(Y)(p10)[77]/46,X,i(Y)(p10) [23]. To our knowledge, such an association has not been previously described. FISH and PCR analysis indicated the presence of at least two copies of the SRY gene in all analyzed cells. Using 17 PCR primers, the Yq breakpoint was shown to map between sY123 (DYS214) and sY121 (DYS212) loci in interval 5O in AZFb region. Possible mechanisms of formation of abnormal Y chromosomes and karyotype-phenotype correlations are discussed.