<prompt> Regarding severe combined immunodeficiency, which is true?Adenosine deaminase deficiencyDecreased circulating lymphocytesNADPH oxidase deficiencyC1 esterase deficiency  <response>: Severe combined immunodeficiency Constellation of genetically distinct syndromes Defects in both humoral cell-mediated immune response MC form - XLR - so more in males; mutation in g chain subunit of cytokine receptors Remaining - AR; deficiency of enzyme ADA 