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

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. I...

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Bibliographic Details
Published inAmerican journal of medical genetics. Part A Vol. 185; no. 1; pp. 208 - 212
Main Authors Armitage, Anna M., Kundra, Monica A., Ghiam, Neda, Atwal, Paldeep S., Morel, Dayna, Hruska, Kathleen S., Torene, Rebecca, Harbour, J. William, Forghani, Irman
Format Journal Article
LanguageEnglish
Published Hoboken, USA John Wiley & Sons, Inc 01.01.2021
Wiley Subscription Services, Inc
Subjects
Blood
Cancer
Chimerism
Genetic screening
Genotyping
monochorionic‐dizygotic twins
Retina
Retinoblastoma
Twins
twin–twin‐transfusion syndrome
monochorionic-dizygotic twins
chimerism
twin-twin-transfusion syndrome
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Summary: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.
ISSN:1552-4825
1552-4833
DOI:10.1002/ajmg.a.61913