Chimerism involving a RB1 pathogenic variant in monochorionic dizygotic twins with twin–twin transfusion syndrome

Anna M. Armitage, Monica A. Kundra, Neda Ghiam, Paldeep S. Atwal, Dayna Morel, Kathleen S. Hruska, Rebecca Torene, J. William Harbour, Irman Forghani

Research output: Contribution to journalArticlepeer-review

Abstract

We report the first case of blood chimerism involving a pathogenic RB1 variant in naturally conceived monochorionic-dizygotic twins (MC/DZ) with the twin–twin-transfusion syndrome (TTTS), presumably caused by the exchange of stem-cells. Twin A developed bilateral retinoblastoma at 7 months of age. Initial genetic testing identified a de novo RB1 pathogenic variant, with a 20% allelic ratio in both twins' blood. Subsequent genotyping of blood and skin confirmed dizygosity, with the affected twin harboring the RB1 pathogenic variant in skin and blood, and the unaffected twin carrying the variant only in blood.

Original languageEnglish (US)
Pages (from-to)208-212
Number of pages5
JournalAmerican Journal of Medical Genetics, Part A
Volume185
Issue number1
DOIs
StatePublished - Jan 2021
Externally publishedYes

Keywords

  • chimerism
  • monochorionic-dizygotic twins
  • twin–twin-transfusion syndrome

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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