A new case of partial 2p trisomy due to de novo interstitial duplication 2p21-22.

We report on a case of "de novo" interstitial duplication of bands 2p21-22 in a 31-month-old female with mild mental retardation and dysmorphism. Cytogenetic investigations were performed on peripheral blood by adding 5-BrdU and 5-FdU. Measurements of enzymatic activity of malate dehydrogenase, whose gene has been mapped on the band 2p23, added reliability to the identification of bands 2p21-22 as the duplicated segment. The authors suggest that the duplication of this segment is able to cause the clinical picture of the syndrome of partial 2p trisomy.