Lack of the human choline transporter-like protein SLC44A2 causes hearing impairment and a rare red blood phenotype

EMBO Mol Med. 2023 Mar 8;15(3):e16320. doi: 10.15252/emmm.202216320. Epub 2023 Jan 25.

Abstract

Blood phenotypes are defined by the presence or absence of specific blood group antigens at the red blood cell (RBC) surface, due to genetic polymorphisms among individuals. The recent development of genomic and proteomic approaches enabled the characterization of several enigmatic antigens. The choline transporter-like protein CTL2 encoded by the SLC44A2 gene plays an important role in platelet aggregation and neutrophil activation. By investigating alloantibodies to a high-prevalence antigen of unknown specificity, found in patients with a rare blood type, we showed that SLC44A2 is also expressed in RBCs and carries a new blood group system. Furthermore, we identified three siblings homozygous for a large deletion in SLC44A2, resulting in complete SLC44A2 deficiency. Interestingly, the first-ever reported SLC44A2-deficient individuals suffer from progressive hearing impairment, recurrent arterial aneurysms, and epilepsy. Furthermore, SLC44A2null individuals showed no significant platelet aggregation changes and do not suffer from any apparent hematological disorders. Overall, our findings confirm the function of SLC44A2 in hearing preservation and provide new insights into the possible role of this protein in maintaining cerebrovascular homeostasis.

Keywords: SLC44A2; blood group antigen; hearing impairment; red blood cells; transfusion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Hearing Loss* / genetics
  • Humans
  • Membrane Glycoproteins / metabolism
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Phenotype
  • Proteomics*

Substances

  • choline transporter
  • Membrane Transport Proteins
  • SLC44A2 protein, human
  • Membrane Glycoproteins