title: Study of two cases of ring 13 chromosome using high-resolution banding.
abstract: The chromosomes of two patients with ring 13 (r13) were studied using high-resolution RBG banding of prometaphase cells. The rings of the two patients differ slightly in breakpoints. Cell with multiple single, double-sized rings, quadruple-sized rings, rod- and ring-shaped fragments, and fragments showing varied states of condensation were seen, as were cells monosomic for chromosome 13. The evolution of these cell lines as a result of sister chromatid exchange, nondisjunction, ring breakage, and premature chromosome condensation is discussed. Clinical features of these patients reflect the heterogeneity of phenotype for r13 patients. Each case includes a feature of trisomy 13. The significance of mosaicism of cell lines in patients bearing ring chromosomes is considered with respect to variation in clinical findings.
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D002460:Cell Line; D002869:Chromosome Aberrations / Q000235:genetics*; D002871:Chromosome Banding; D025063:Chromosome Disorders; D002901:Chromosomes, Human, 13-15 / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008214:Lymphocytes / Q000648:ultrastructure; D009030:Mosaicism; D012854:Sister Chromatid Exchange