Figure 3.

Characterization of the 7q11.23 CNVs by quantitative PCR-based methods and FISH. (A) Representative genotypes at the multiple-copy PSV (indel at exon 11 of POM121, block C) and microsatellites BASTR1 (block A) and BBSTR1 (block B) in individuals with different CNVs. Individual 1 is a normal control, carrying six alleles per LCR block and two alleles at the WBS region. BASTR1 shows eight alleles because it recognizes four loci, one deleted in WBS patients (D7S489B), and three located in blocks A. BBSTR1 recognizes three loci, one from each block B. Individual 2 is a WBS patient with the most common 1.55-Mb deletion that leads to the loss of one block B and the entire single-copy region in between. Individuals 3 and 4 carry deletion-type CNVs resulting in deletion of the centromeric-type blocks C, A, and B (3, WBS-CNV1Del) or of only the telomeric-type blocks A and B (4, WBS-CNV2Del). Individuals 5 and 6 carry duplication-type CNVs including all three blocks sequences (5, WBS-CNV1Dup) or just block B (6, WBS-CNV3Dup). Asterisks over each peak indicate the number of alleles, as predicted by dosage analysis (US, unique sequence). The predicted number of alleles is indicated by asterisks on top of each peak. (B) Dual-color interphase FISH in nuclei from the same individuals 1–5 with BACs RP11–204E14 (BZ724405) (block B), and RP11–622P13 (AC073846) (WBS region), giving red and green signals, respectively. Individual 1 shows the normal pattern in both chromosomes. Individual 2 shows a deletion of the green probe and a red signal in one chromosome due to a deletion mediated by inter-block B recombination. In individual 3, a red spot in one chromosome is missing due to deletion of block Bc, while in individual 4 the missing signal corresponds to a block B located at telomeric side. Individual 5 shows an extra signal in one chromosome corresponding to an additional block B present at the centromeric side. (C) Schematic representation of the hypothetical structure of the region as shown by FISH signals.