For further analysis we restricted attention to the three common variants in 18 heterogeneous HSCR patients (Table 1): deletion in intron 11 of MAPK10, duplication involving exon 2 of ZFHX1B, and duplication in the 5′UTR of SOX2. The MAPK10 deletion, on chromosome 4 at location 87,195,268 (hg18), was a 3.5 kb lesion detected using 13 probes in a single sample (Figure 1A). This evidence concerns the gene MAPK10 and Hirschsprung disease.