Conventional karyotyping, FISH, SKY and CGH analyses showed that the region distal to the MLL locus on 11q23 was lost and replaced by the distal region of 11p, leading to a partial trisomy of 11p and a partial monosomy of 11q.
If array CGH had been performed along with the fetal karyotype, the cryptic partial trisomy 2 could have been identified in a more timely manner to assist in the prenatal counseling of this family.
Using FISH and CGH techniques, it was found that the ring chromosome was a partial trisomy of chromosome 7, and the region implicated corresponded to 7p13-q21.