De novo ?pure? partial trisomy (6)(p22.1?pter) in a chromosome 15 with an enlarged satellite, identified by microdissection

We report on a newborn boy with a congenital heart defect, severe pre- and postnatal growth retardation, feeding problems, facial anomalies and unilateral hydronephrosis. Cytogenetic analysis showed extra chromosomal material on the short arm of one chromosome 15 that at first sight could be mistaken for a chromosomal variant and could not be identified with conventional banding techniques. Chromosome analysis of the parents showed that both had a normal karyotype. Microdissection of five copies of the aberrant chromosome 15, amplification of the dissected chromosomal material by DOP-PCR and subsequent reverse painting was performed and disclosed that the patient had a de novo 46,XY,der(15)(6pter-->6p22.1::15p12-->15qter) karyotype with a "pure" trisomy of chromosome region 6p22.1-->6pter. The associated phenotypic anomalies are compared with other reported cases with a distal duplication of chromosome 6p.