Medknow Publications on behalf of Indian Society of Human Genetics
Abstract
This article reports a case of four-month-old female infant referred to
Division of Human Genetics, St. Johns' Medical College, for karyotyping
with suspicion of Down syndrome. On karyotyping all analysed spreads
showed trisomy 21 but a few spreads (6.66%) showed fragment X. X was
broken at the centromere and both short and long arms were present in
the spread. GTG bands of the two fragments correlated with the normal X
counter parts. The mechanism behind isochromosome formation is
discussed. Thus, this case is free trisomy 21 for Down syndrome and a
mosaic for the X structural anomaly
