PMC:1852721 / 45876-47016 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/1852721","sourcedb":"PMC","sourceid":"1852721","source_url":"https://www.ncbi.nlm.nih.gov/pmc/1852721","text":"Reciprocal X-autosome translocations have been important for finding the chromosomal location of genes determining X-linked disorders (and the nature of those genes). Sporadic cases of an X-linked recessive disorder in a female with such a translocation was sometimes not only the main or even the only evidence that the gene was on the X chromosome, but also the breakpoint on X indicated the precise location of the gene. In females with an X-autosome translocation, the derivative X chromosome (the derivative chromosome with the centromere of the X) is active in all cells; if the derivative X chromosome were inactive (lyonized), its autosomal component would likewise be inactive, with cell-lethal effects due to autosomal monosomy. Thus, the normal X chromosome is the inactive one, and the derivative X—which may have disruption of the gene at the breakpoint—is the active one. The breakpoint, therefore, marks the site of the gene responsible for the disorder in the patient. Duchenne muscular dystrophy was among the first disorders to be mapped by this method; table 1 in the preface of MIM12 (1998) tabulated 16 other examples.2","tracks":[]}