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Mosaicism for a small marker chromosome resulting from a familial Robertsonian translocation (21;22)
Author(s) -
Arab Sara,
Chitayat David,
Gardner H Allen,
Winsor Elizabeth Jt
Publication year - 1999
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1034/j.1399-0004.1999.560504.x
Subject(s) - chromosomal translocation , marker chromosome , robertsonian translocation , biology , genetics , karyotype , chromosome , chromosome 21 , genetic marker , chromosomal rearrangement , gene
A mosaic marker chromosome found in amniotic fluid was shown to have originated from the proximal part of the long arm of chromosome 22. This marker is unusual because it is the result of a deletion of a maternally inherited Robertsonian 21;22 translocation. It is suggested that the deletion and marker formation probably occurred post zygotically in the fetus. This rare case illustrates the difficulty in estimating risk of fetal abnormalities associated with de novo marker chromosomes. In this example, although the ‘extra’ marker chromosome contains euchromatin, the karyotype may still be ‘balanced’.