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. Cells 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 of 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.
|Original language||English (US)|
|Number of pages||10|
|Journal||American Journal of Human Genetics|
|State||Published - Jan 1 1981|
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