["Free" 9p trisomy in a male child with severe mental retardation (author's transl)].

A new case of free 9p trisomy is described. The GTG banding technique and the Giemsa-11 method showed that the extra chromosome comprised precisely the 9pter leads to q12 segment. The carrier is an eleven-year-old male child with typical facial features: globulous nose, antimongoloid slant of palpebral fissures, downward turning of mouth angels and winged ears, severe mental retardation particularly regarding language and characteristic dermatoglyphics.