Blood work/Immunoglobulin A deficient/Tourettes?

[texas5]

My 15 year old son has ADD & Tourettes since age 9. I work for a doctor (Pain Mgmt) and he ordered alot of blood work on my son at my request. I can't get his Neurologist or Pediatrician to order blood work. I got the results bad and he if very deficient in Vitamin D and his Immunoglobulin A is low. It is 47 and the range is 57-300 mg/dl. I can't take him for his well-check up until June and the doctor I work for doesn't know alot about Immunoglobulin A deficiency. Do anybody know what it means? Do I need to get him to a doctor asap. Is it a life threatening condition? Do you think it has anything to do with his Tourtettes/Tics?