Brown et al. [1] reported that only one of ten HAAA patients was positive for HBsAb and HBcAb, with the other nine being seronegative for hepatitis A, B and C. Safadi et al. [8] found that all 17 HAAA patients studied were seronegative for hepatitis A–E and G, and TTV. The gene discussed is EXT1; the disease is hepatitis A virus infection.