Mosaic inv dup(8p) marker chromosome with stable neocentromere suggests neocentromerization is a post-zygotic event

Abstract

Marker chromosomes containing active human neocentromeres have been described in individuals where the chromosomes are non-mosaic, suggesting that they are mitotically stable, but also in individuals where there is mosaicism, raising the possibility of neocentromere instability. We report two independently ascertained individuals who are mosaic for a supernumerary marker chromosome, shown by reverse chromosome painting to have an 8p origin, resulting in mosaicism for tetrasomy 8p23.1→pter in the patient. The markers have a primary constriction but show no detectable centromeric α-satellite DNA. The marker in Patient 1 demonstrated no centromere protein CENP-B binding, but associated with nin..