MECOM-associated syndrome: a heterogeneous inherited bone marrow failure syndrome with amegakaryocytic thrombocytopenia

Blood Adv. 2018 Mar 27;2(6):586-596. doi: 10.1182/bloodadvances.2018016501.

Abstract

Heterozygous mutations in MECOM (MDS1 and EVI1 complex locus) have been reported to be causative of a rare association of congenital amegakaryocytic thrombocytopenia and radioulnar synostosis. Here we report on 12 patients with congenital hypomegakaryocytic thrombocytopenia caused by MECOM mutations (including 10 novel mutations). The mutations affected different functional domains of the EVI1 protein. The spectrum of phenotypes was much broader than initially reported for the first 3 patients; we found familial as well as sporadic cases, and the clinical spectrum ranged from isolated radioulnar synostosis with no or mild hematological involvement to severe bone marrow failure without obvious skeletal abnormality. The clinical picture included radioulnar synostosis, bone marrow failure, clinodactyly, cardiac and renal malformations, B-cell deficiency, and presenile hearing loss. No single clinical manifestation was detected in all patients affected by MECOM mutations. Radioulnar synostosis and B-cell deficiency were observed only in patients with mutations affecting a short region in the C-terminal zinc finger domain of EVI1. We propose the term MECOM-associated syndrome for this heterogeneous hereditary disease and inclusion of MECOM sequencing in the diagnostic workup of congenital bone marrow failure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anemia, Aplastic / diagnosis
  • Anemia, Aplastic / genetics*
  • Bone Marrow Diseases / diagnosis
  • Bone Marrow Diseases / genetics*
  • Bone Marrow Failure Disorders
  • Congenital Bone Marrow Failure Syndromes
  • DNA-Binding Proteins / blood
  • Female
  • Genetic Association Studies*
  • Genetic Heterogeneity*
  • Genetic Predisposition to Disease*
  • Hematopoietic Stem Cells / cytology
  • Hematopoietic Stem Cells / metabolism
  • Hemoglobinuria, Paroxysmal / diagnosis
  • Hemoglobinuria, Paroxysmal / genetics*
  • Humans
  • Lymphocyte Subsets / immunology
  • Lymphocyte Subsets / metabolism
  • MDS1 and EVI1 Complex Locus Protein / genetics*
  • Male
  • Mutation
  • Pedigree
  • Thrombocytopenia / diagnosis
  • Thrombocytopenia / genetics*
  • Transcription Factors / blood

Substances

  • DNA-Binding Proteins
  • MDS1 and EVI1 Complex Locus Protein
  • MECOM protein, human
  • Transcription Factors
  • ZBTB7B protein, human

Supplementary concepts

  • Congenital amegakaryocytic thrombocytopenia