Figure 4.

Uniparental disomy (UPD). In these cases, the log R ratio is consistent with normal copy number for all cases. (A) Complete isodisomy of chromosome 14 with loss of heterozygosity (LOH) for the entire chromosome in patient no. 22. This is consistent with the mechanism of monosomy rescue. (B) UPD of chromosome 15 in patient no. 29. Note the regions of LOH near the centromere and across the middle of the chromosome, which are interrupted by regions of heterozygosity, suggesting origin in meiosis II, with evidence of regions of recombination. (C) Segmental UPD of 11p11.2 to p-terminus in the DNA from cultured skin (10%) from patient no. 24. (D) Analysis of DNA from pancreatic tissue in patient no. 24, which had 30% mosaicism for the 11p LOH. This patient has a clinical diagnosis of focal hyperinsulinism.