AP1S3 and achondroplasia: Although a substantial patient subset (n = 249) was screened for the entire coding region, the rest were sequenced only for exon 2, given that the only known AP1S3 mutations (p.Phe4Cys, p.Arg33Trp) map to this genomic segment 2.5, 9 This revealed 24 European cases (2 patients with ACH, 4 with GPP, 14 with PPP, and 4 with multiple diagnoses) bearing the p.Phe4Cys or p.Arg33Trp changes (see Table E8 in this article's Online Repository at www.jacionline.org).