Clinical and molecular cytogenetic characterization of two patients with partial trisomy 1q41-qter: Further delineation of partial trisomy 1q syndrome

We report the clinical and molecular cytogenetic characterization of two pa tients with partial trisomy 1q. The first patient is a currently 11-year-ol d female proposita with a de novo unbalanced translocation 46,XX,der(8)(8qt er-8p23.3::1q41-1qter), leading to a partial trisomy 1q41-qter and a partia l monosomy for 8p23.3-pter. The most prominent clinical features of the gir l are a triangular face, almond-shaped eyes, low-set ears, short stature wi th relatively long legs, and mild psychomotor retardation. To our knowledge , the cytogenetic aberration in this girl is the most proximal partial tris omy iq leading to a mild phenotype. Recently, we identified a second patien t with a similar partial trisomy 1q combined with a cri du chat syndrome ca used by a de novo unbalanced translocation 46,XX,der(5) (5qter-5p13.1::1q41 -1qter). Comparison of the phenotype of the two girls as well as with alrea dy published trisomy 1q cases was performed, and fluorescence in situ hybri dization probes from selected YACs were used to delineate the extent of the partial trisomy in more detail. (C) 2001 Wiley-Liss, Inc.