45,X/46,X,+r(X) Can have a distinct phenotype different from Ullrich- Turner syndrome

Markus Grompe, N. Rao, F. F B Elder, C. T. Caskey, F. Greenberg

Research output: Contribution to journalArticle

35 Scopus citations


We present a patient with 45,X/46,X,+r(X) mosaicism and lack of inactivation of either the normal or the ring X in the 46,X,+r(X) cells. The patient has mental retardation, syndactyly, minor facial anomalies, and a congenital heart defect. Although most patients with 45,X/46,X,+r(X) have the Ullrich-Turner syndrome, 2 previously described patients with this karyotype also had a distinct phenotype consisting of severe mental retardation, syndactyly, and abnormal face. The unusually severe phenotype in these patients was thought to be due to lack of X-inactivation of the ring X chromosome. The findings in our patient support this hypothesis.

Original languageEnglish (US)
Pages (from-to)39-43
Number of pages5
JournalAmerican Journal of Medical Genetics
Issue number1
Publication statusPublished - 1992
Externally publishedYes



  • mental retardation
  • microcephaly
  • ring chromosome
  • syndactyly
  • X-inactivation

ASJC Scopus subject areas

  • Genetics(clinical)

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