Twenty-nine as yet unreported ring chromosomes were characterized in detail by cytogenetic and molecular techniques. for FISH (fluorescence in situ hybridization) previously published high resolution approaches such as multicolor banding (MCB), subcentromere-specific multi-color-FISH (cenM-FISH) and two to three-color-FISH applying locus-specific probes were used. Overall, ring chromosome derived from chromosomes 4 (one case), 10 (one case), 13 (five cases), 14, (three cases), 18 (two cases), 21 (eight cases), 22 (three cases), X (five cases) and Y (one case) were studied. Eight cases were detected prenatally, eight due developmental delay and dysmorphic signs, and nine in connection with infertility and/or Turner syndrome. in general, this report together with data from the literature, supports the idea that ring chromosome patients fall into two groups: group one with (severe) clinical signs and symptoms due to the ring chromosome and group two with no obvious clinical problems apart from infertility.DAADBMBF/DLRElse Kroner-Fresenius-StiftungCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ Jena, Jena Univ Hosp, Inst Human Genet, D-07743 Jena, GermanyUniversidade Federal de São Paulo, Dept Morphol & Genet, BR-04023900 São Paulo, BrazilUniv Magdeburg, Inst Humangenet, D-39120 Magdeburg, GermanyNatl Med Ctr, Minsk 220053, ByelarusBelarus State Med Univ, Minsk 220116, ByelarusInst Human Genet & Anthropol, D-72076 Tubingen, GermanyUniv Klinikum Essen, Inst Humangenet, D-45122 Essen, GermanyMVZ WagnerStibbe, D-30159 Hannover, GermanyUniv Zagreb, Sch Med, Croatian Inst Brain Res, Zagreb 1000, CroatiaEurogenetica SA, Athens 11527, GreeceUniversidade Federal de São Paulo, Dept Morphol & Genet, BR-04023900 São Paulo, BrazilDAAD: D07/00070BMBF/DLR: BLR 10/006Else Kroner-Fresenius-Stiftung: 2011_A42CAPES: 2333-11-2Web of Scienc
