Functional disomy of the Xq28 chromosome region

Eur J Hum Genet. 2005 May;13(5):579-85. doi: 10.1038/sj.ejhg.5201384.

Abstract

We report on two patients, a boy and a girl, with an additional Xq28 chromosome segment translocated onto the long arm of an autosome. The karyotypes were 46,XY,der(10)t(X;10)(q28;qter) and 46,XX,der(4)t(X;4)(q28;q34), respectively. In both cases, the de novo cryptic unbalanced X-autosome translocation resulted in a Xq28 chromosome functional disomy. To our knowledge, at least 17 patients with a distal Xq chromosome functional disomy have been described in the literature. This is the third report of a girl with an unbalanced translocation yielding such a disomy. When the clinical features of both patients are compared to those observed in patients reported in the literature, a distinct phenotype emerges including severe mental retardation, facial dysmorphic features with a wide face, a small mouth and a thin pointed nose, major axial hypotonia, severe feeding problems and proneness to infections. A clinically oriented FISH study using subtelomeric probes is necessary to detect such a cryptic rearrangement.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Aneuploidy*
  • Chromosomes, Human, Pair 10 / genetics*
  • Chromosomes, Human, Pair 4 / genetics*
  • Chromosomes, Human, X / genetics*
  • Female
  • Humans
  • Infant
  • Karyotyping
  • Male
  • Translocation, Genetic*