text: Adenylate Kinase 2 (AK2) deficiency in humans causes hematopoietic defects associated with sensorineural deafness.  Reticular dysgenesis is an autosomal recessive form of human combined immunodeficiency.  It is also characterized by an impaired lymphoid maturation and early differentiation arrest in the myeloid lineage.  AK2 deficiency results in absent or a large decrease in the expression of proteins.  AK2 is specifically expressed in the stria vascularis of the inner ear which indicates why individuals with an AK2 deficiency will have sensorineural deafness.