Clinical and molecular‐cytogenetic studies in seven patients with ring chromosome 18

摘要: We report the results of detailed clinical and molecular-cytogenetic studies in seven patients with ring chromosome 18. Classical cytogenetics fluorescence situ hybridization (FISH) analysis 18 painting probe identified five non-mosaic two complex mosaic 46,XX,dup(18)(p11.2)/47,XX,dup(18)(p11.2),+r(18) 46,XX,dup(18)(p11.32)/47,XX,dup(18)(p11.32),+r(18) cases. FISH was performed for precise characterization breakpoints using 18-specific short-arm paint, centromeric, subtelomeric, a panel fifteen Alu- DOP-PCR YAC probes. The were assessed an average resolution approximately 2.2 Mb. In all r(18) chromosomes, 18q terminal deletions ranging from 18q21.2 to 18q22.3 ( 35 9 Mb, respectively) found, whereas only four cases could loss 18p material be demonstrated. dup(18) chromosomes as inv dup(18)(qter-->p11.32::q21.3-->qter) dup(18)(qter-->p11.32::p11.32-->p11.1: :q21.3-->qter)pat, no evidence deletion. A novel inter-intrachromatid mechanism formation duplications is proposed. Although effect "ring instability syndrome" cannot excluded, phenotypes our characteristic features 18q- 18p- syndromes are compared correlated analyzed genotypes. It has been observed that short neck absence cardiac anomalies may related deletion chromosome.