Abstract
The phenotypic findings of three patients whose karyotypic interpretations were uncertain were compared to patients with trisomy 9 (pter → ql to q3). One with an extra, small acrocentric chromosome and another with a trisomy due to an inherited C/G translocation have a phenotype compatible with the trisomy 9 (pter → ql) syndrome. In a third patient reported with 47, XY, ?16+, the trisomy 9p probably extends past the ql region.