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We report on a currently six-year-old patient with a de novo complex chromosome rearrangement (CCR) involving chromosomes 2 and 12. A translocation 2;12 that appeared to be reciprocal after standard banding turned out to be a complex event with seven breaks after molecular cytogenetic analyses. Array CGH analysis showed no imbalances at the breakpoints but revealed an additional microdeletion of about 80 kb on chromosome 11. The same deletion was also present in the phenotypically normal father. The patient showed relatively mild mental retardation, defined mainly as impaired speech development (orofacial dyspraxia) and psychomotor retardation. In addition, mild dysmorphic facial features like hypertelorism, a prominent philtrum and down-turned corners of the mouth were observed. We narrowed down all breakpoint regions to about 100 kb, using a panel of mapped bacterial artificial chromosome (BAC) clones for fluorescence in situ hybridization (FISH). BACs spanning or flanking all seven breakpoints were identified and no chromosomal imbalances were found consistent with the array CGH results. Our investigations resulted in the following karyotype: 46,XY,t(2;12)(2pter→2p25.3::2p23.3→2p25.2::2p23.3→2p14::2q14.3→2p14::2q14.3→2q14.3::12q 12→12qter;12pter→12q12::2p25.3→2p25.2::2q14.3→2qter). Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The article discusses Localization of the human anterior gradient-2 gene (AGR2) to chromosome band 7p21.3 by radiation hybrid mapping and fluorescence in situ hybridisation. By using the GeneBridge 4 radiation hybrid screening panel, AGR2 was localized 2.74 cR centromeric to AFMAO84WH5 and 3.98 cR telomeric to D75673. Although somatic cell hybrid maps are not formally linked to cytogenetic maps, the most likely location of AGR2 is 7p2l .3. Two overlapping YACs containing the AGR2 gene were used to confirm the RH mapping data by FISH.

The article reveals the method on assignment of STAC to human chromosome band 3p22.3 between D3S3718 and D3S1611 by fluorescence in situ hybridization and southern blot analysis. STAC, a novel neuron-specific protein has two functional domains, a cysteine-rich domain and an SH3 domain in neurons. It has been determined the chromosome location of the STAC gene in mouse to chromosome 9 and by radiation hybrid mapping in human to 3p24→ p22. The results concludes that this gene is located about three megabases distal to the more telomeric chromosome breakpoint and thus it is not involved in the formation of this neurological disease.