Mutations in MECOM, Encoding Oncoprotein EVI1, Cause Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia

Am J Hum Genet. 2015 Dec 3;97(6):848-54. doi: 10.1016/j.ajhg.2015.10.010. Epub 2015 Nov 12.


Radioulnar synostosis with amegakaryocytic thrombocytopenia (RUSAT) is an inherited bone marrow failure syndrome, characterized by thrombocytopenia and congenital fusion of the radius and ulna. A heterozygous HOXA11 mutation has been identified in two unrelated families as a cause of RUSAT. However, HOXA11 mutations are absent in a number of individuals with RUSAT, which suggests that other genetic loci contribute to RUSAT. In the current study, we performed whole exome sequencing in an individual with RUSAT and her healthy parents and identified a de novo missense mutation in MECOM, encoding EVI1, in the individual with RUSAT. Subsequent analysis of MECOM in two other individuals with RUSAT revealed two additional missense mutations. These three mutations were clustered within the 8(th) zinc finger motif of the C-terminal zinc finger domain of EVI1. Chromatin immunoprecipitation and qPCR assays of the regions harboring the ETS-like motif that is known as an EVI1 binding site showed a reduction in immunoprecipitated DNA for two EVI1 mutants compared with wild-type EVI1. Furthermore, reporter assays showed that MECOM mutations led to alterations in both AP-1- and TGF-β-mediated transcriptional responses. These functional assays suggest that transcriptional dysregulation by mutant EVI1 could be associated with the development of RUSAT. We report missense mutations in MECOM resulting in a Mendelian disorder that provide compelling evidence for the critical role of EVI1 in normal hematopoiesis and in the development of forelimbs and fingers in humans.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Bone Marrow / abnormalities
  • Bone Marrow / metabolism
  • Child
  • Child, Preschool
  • DNA-Binding Proteins / genetics*
  • Exome
  • Female
  • Gene Expression Regulation
  • Hematopoiesis / genetics
  • Humans
  • MDS1 and EVI1 Complex Locus Protein
  • Male
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation, Missense*
  • Protein Structure, Tertiary
  • Proto-Oncogenes / genetics*
  • Radius / abnormalities*
  • Radius / metabolism*
  • Sequence Analysis, DNA
  • Signal Transduction
  • Synostosis / genetics*
  • Synostosis / metabolism
  • Thrombocytopenia / congenital*
  • Thrombocytopenia / genetics
  • Thrombocytopenia / metabolism
  • Transcription Factor AP-1 / genetics
  • Transcription Factor AP-1 / metabolism
  • Transcription Factors / genetics*
  • Transcription, Genetic
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism
  • Ulna / abnormalities*
  • Ulna / metabolism*


  • DNA-Binding Proteins
  • MDS1 and EVI1 Complex Locus Protein
  • MECOM protein, human
  • Transcription Factor AP-1
  • Transcription Factors
  • Transforming Growth Factor beta

Supplementary concepts

  • Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia