Familial marker in a Down Syndrome Child.

Four months old, female child, referred for cytogenetic analysis, showed mosaiciam for the marker chromosome. Her karyotype: 47,XX,+21/48,XX+21 mar (pat). The karyotype of her mother & her sib were normal. Her father showed, similar to the proband, mosaicism for the marker ie 46,XY/47,XY, + mar. AgNOR technique determined the marker as fused short arms of the acrocentric chromosome. Four months old, female child, referred for cytogenetic analysis, showed mosaiciam for the marker chromosome. Her karyotype: 47,XX,+21/48,XX+21 mar (pat). The karyotype of her mother & her sib were normal. Her father showed, similar to the proband, mosaicism for the marker ie 46,XY/47,XY, + mar. AgNOR technique determined the marker as fused short arms of the acrocentric chromosome.