Which of the following systemic diseases does/do NOT predispose a patient to periodontitis?
1. Cyclic neutropenia.
2. Diabetes mellitus.
3. Acquired immunodeficiency syndrome.
4. Hereditary hypohydrotic ectodermal dysplasia.

• (1) (2) (3)

• (1) and (3)

• (2) and (4)

• Correct answer

  (4) only

• All of the above.