Reticular Dysgenesis and Mitochondriopathy Induced by Adenylate Kinase 2 Deficiency with Atypical Presentation

Sci Rep. 2019 Oct 31;9(1):15739. doi: 10.1038/s41598-019-51922-2.

Abstract

Reticular dysgenesis is an autosomal recessive form of severe combined immunodeficiency (SCID) that usually manifests in newborns. It is a unique example of an immune deficiency that is linked to dysfunctional mitochondrial energy metabolism and caused by adenylate kinase 2 (AK2) deficiency. It is characterized by an early differentiation arrest in the myeloid lineage, impaired lymphoid maturation, and sensorineural hearing loss. In this study, a novel AK2 homozygous mutation, c.622 T > C [p.Ser208Pro], was identified in an Old Order Amish patient through whole exome sequencing. Functional studies showed that the patient's cells have no detectable AK2 protein, as well as low oxygen consumption rate (OCR), extracellular acidification rate (ECAR) and proton production rate (PPR). An increased production of reactive oxygen species, mitochondrial membrane permeability, and mitochondrial mass, and decreased ATP production, were also observed. The results confirm the pathogenicity of the AK2 mutation and demonstrate that reticular dysgenesis should be considered in Amish individuals presenting with immune deficiency. We also describe other pathophysiological aspects of AK2 deficiency not previously reported.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylate Kinase / deficiency
  • Adenylate Kinase / genetics*
  • Bone Marrow / pathology
  • Cell Membrane Permeability
  • Child, Preschool
  • Energy Metabolism
  • Exome Sequencing
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Homozygote
  • Humans
  • Leukopenia / diagnosis*
  • Leukopenia / genetics
  • Male
  • Mitochondria / metabolism*
  • Mitochondrial Membranes / metabolism
  • Oxygen Consumption
  • Pedigree
  • Polymorphism, Single Nucleotide
  • Reactive Oxygen Species / metabolism
  • Severe Combined Immunodeficiency / diagnosis*
  • Severe Combined Immunodeficiency / genetics

Substances

  • Reactive Oxygen Species
  • Adenylate Kinase
  • adenylate kinase 2

Supplementary concepts

  • Reticular dysgenesis