The synonymous mutation c.351C>G (p.Thr117=) in GATA2 leads to GATA2 haploinsufficiency. (A) Agarose gel electrophoresis of RT-PCR product spanning exons 3 to 4 from an AML sample from patient III-1 and a control bone marrow (BM) sample and chromatograms of PCR products. Asterisk indicates mutation/aberrant splice site. (B) Agarose gel electrophoresis of RT-PCR product spanning GATA2 exons 2 to 5 from cultured skin fibroblasts from the immunodeficiency patient (ID) and control cultured skin fibroblasts, as well as chromatograms of PCR products. (C) Agarose gel electrophoresis of RT-PCR product specific for aberrant splice product from cultured skin fibroblasts from the ID patient and control cultured skin fibroblasts. (D) Schematic overview of aberrant splicing product and putative truncated GATA2 protein generated by GATA2 c.351C>G. Blue arrow labeled with “ca” indicates cryptic splice acceptor activated by the mutation; blue arrow labeled with “cd” indicates cryptic splice donor; blue arrow labeled with “T” indicates premature stop at cDNA position 571; light orange box indicates deleted 136-bp mRNA; light blue box indicates stretch of 55 altered amino acids.