[Increased activity of adenine phosphoribosyl transferase in a child trisomic for 16q22.2 to 16qter due to malsegregation of a t(16;21) (q22.2;q22;2)pat (author's transl)].

Two cousins with trisomy for the distal third of 16q due to a familial translocation, t(16;21)(q22.2;q22-2), are reported. The APRT gene locus could be assigned to 16q22.2 to 16qter. The phenotypic similarities of the first patient, who had trisomy 16q22.3 to 16qter and monosomy 21q22.3, to six other patients with partial trisomy 16q reported in literature allows the delineation of a syndrome due to trisomy 16qter. In the second patient, with trisomy 16q22.3 to 16qter and trisomy 21pter to 21q22.2 similar features are present but in association with the classical symptoms of trisomy 21.