Replication banding and molecular studies of a mosaic, unbalanced dic(X;15)(Xpter→Xq26.1::15p11→15qter)

A. Scheuerle, J. L. Zenger-Hain, D. L. Van Dyke, D. H. Ledbetter, F. Greenberg, L. G. Shaffer

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We present a patient with a chromosomal mosaicism involving the X chromosome. One cell line is 45,X and the other has a de novo paternally derived dicentric X;15 translocation. Her karyotype is therefore 45,X/45,X,dic(X;15)(Xpter→Xq26.1::15p11→15 qter) based on G-banding. The presence of 2 centromeres on the derivative X was confirmed by fluorescence in situ hybridization (FISH) and a deletion of Xq26.1→qter was confirmed by polymerase chain reaction (PCR) using DXS52 and DXYS154. Replication banding studies indicate that the derivative X is late replicating. Based on these studies, it is unclear whether inactivation has spread to proximal 15q. The patient has a unique phenotype distinct from Ullrich-Turner or Prader-Willi syndromes, but includes ataxia and language delay which are commonly seen in Angelman syndrome. These findings are contrary to those anticipated since deficiency of paternal genes at 15q12 typically leads to Prader-Willi syndrome. Molecular analysis of PCR-based polymorphisms of chromosome 15 and X indicates that uniparental disomy is not present for the X chromosome or chromosome 15 in either cell line. It is hypothesized that her phenotype results from the interaction of the 2 abnormal genotypes. Each abnormality may be diluted by the mosaicism and, in the derivative X line, by the possible variation among cells of inactivation spreading to chromosome 15.

Original languageEnglish (US)
Pages (from-to)403-408
Number of pages6
JournalAmerican journal of medical genetics
Issue number4
StatePublished - 1995


  • FISH
  • PCR
  • X chromosome
  • de novo paternal deletion
  • inactivation
  • mosaicism

ASJC Scopus subject areas

  • Genetics(clinical)


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