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Abstract #14226 Published in IGR 8-3
A highly complex rea (2;3;11) and aniridia by position effect
Rivera H; Ayala Madrigal ML; Barros Nunez JP; Arnaud Lopez L; Maloney V; Crolla JACytogenetic and Genome Research 2006; 114: 83-88
A two-year-old boy presenting with bilateral aniridia and psychomotor retardation had a de novo (2;3;11) highly complex rearrangement which was characterized as far as possible by means of G-banding and FISH assays with multiple probes including cosmids for the Wilms, Aniridia, Genital anomalies and Retardation (WAGR) region, alphoid repeats for chromosomes 2, 3 and 11, subtelomere probes for 2p/2q, 3p/3q and 11q and BACs for 2q32 and 3q13. We identified ˜ 15 breakpoints with at least three interchromosomal and three intrachromosome anomalies involving chromosome 11. Both parents had normal karyotypes and no cryptic 11p rearrangements revealed by the chromosome 11 cosmid panel. The lack of a deletion of PAX6 pointed to the direct insertion of an ˜ 300-kb segment involving the cosmids FO2121 and AO4160, and more specifically the insertion's proximal breakpoint in the ˜ 150-kb segment between FO2121 and FAT5 (PAX6) as the responsible factor for the patient's aniridia via a position effect resulting in functional haploinsufficiency of the PAX6 gene. This case illustrates the importance of recognizing that de novo complex chromosomal rearrangements found in patients with diverse clinical features may contribute to the phenotype, but that multiple mechanisms and higher levels of complexity may be unmasked by high resolution molecular cytogenetic studies.
Dr. H. Rivera, Centro de Investigacion Biomedica de Occidente, Instituto Mexicano del Seguro Social, Ap. Postal 1-3838, Guadalajara, Jal, Mexico
Classification:
3.4.1 Linkage studies (Part of: 3 Laboratory methods > 3.4 Molecular genetics)
