Severe phenotype resulting from an active ring X chromosome in a female with a complex karyotype: characterisation and replication study.

摘要: We report on the characterisation of a complex chromosome rearrangement, 46,X,del(Xq)/47,X,del(Xq),+r(X), in female newborn with multiple malformations. Cytogenetic and molecular methods showed that del(Xq) contains XIST locus is non-randomly inactivated all metaphases. The tiny r(X) gave positive FISH signal UBE1, ZXDA, MSN cosmid probes, but not probe. Moreover, it has an active status, as shown by very short (three hour) terminal BrdU pulse followed fluorescent anti-BrdU antibody staining. normal X paternal origin both rearranged chromosomes originate from same maternal chromosome. suggest abnormal result three point breakage isodicentric idic(X)(q21.1). Finally, phenotype our patient compared to other published cases and, despite absence any 45,X clone, appears similar those 45,X/46,X,r(X) karyotype where active.