Report of a new case and clinical delineation of mosaic trisomy 9 syndrome.

A newborn girl with trisomy 9 mosaicism is reported. Clinical findings included major malformations: bilateral hip dislocation, dislocation of the left knee, extreme micrognathia, and microsomy. Up to date, 11 liveborn infants with trisomy 9 have been reported, which allows us to make a karyotype/phenotype correlation. Minimal clinical diagnostic criteria are defined, on the basis of which the presence of this syndrome can be suspected.