<prompt> Most common genetic factor in Neisseria infection isMale genderHLA b27Complement deficiencyIgG deficiency  <response>: Complement deficiencies are said to comprise between 1 and 10 of all primary immunodeficiencies. The genetic deficiency of early components of the classical pathway C1q, C1rs, C2, C4 tends to be linked with autoimmune diseases, whereas C5 to C9 deficiency may have enhanced susceptibility to meningococcal disease. Reference: Textbook of Microbiology; Anathanarayan and panickers; 10th edition; Pg: 232 