Figure 3.

Mapping the deletion breakpoint of USH2A del exon 4 in family 309. A. Based on array CGH results PCR primers were designed to amplify across the deletion breakpoint on genomic DNA in family 309. Sequence analysis identified the exact breakpoint as USH2A: c.781_784+1375del. The segments in red represent the deleted regions, and grey the non-deleted. B. PCR products from amplification across the deletion breakpoint on genomic DNA in family 309. A smaller band, representing the deletion allele, is present in the proband from family 309 but not on control. A larger band amplifies in control, corresponding to the non-deletion allele. The proband from family 309 is heterozygous for the deletion, however, the non-deletion allele has not amplified most likely due to preferential amplification of the shorter PCR product.