A rare case of a liveborn with free, de novo and partial trisomy 12 and an unusual phenotype.

Abstract

Individuals with free and total trisomy 12 are rare and always mosaic. Incidences of partial trisomy 12 are more frequent and are classified into trisomy 12p and trisomy 12q. The phenotype of both trisomy 12p and trisomy 12q is well described in the literature. We report here, the rare occurrence of a liveborn with free and de novo trisomy 12, albeit not the whole chromosome. The clinical description of this infant includes characteristics of trisomy 12p and trisomy 12q syndromes. Few additional anomalies present in the infant are unaccounted for by both syndromes. We anticipate that these characteristics are caused by trisomy 12q13, which to our knowledge has not been reported in a trisomy before.