While there is sufficient evidence to supportthe frameshift mutation in Gimap5 asthe cause of lymphopenia, we could not exclude that either Gimap1 or Gimap3 play arole, as they are located within the lymphopenia critical interval betweenD4Rhw6 and IIsnp3 as well as within the PAC used in the transgenic rescue oflymphopenia [7]. The gene discussed is GIMAP1; the disease is lymphopenia.