How common is a partial iga deficiency? mine is 37 mg/dl

Selective IgA defic.: Prevalence varies by population, but is on the order of up to 1 in 333 people making it relatively common for a genetic disease. It is more common in males than in females. IgA is primarily in secretions of the mucosal surfaces, including tears, saliva, colostrum, genital, respiratory and gastrointestinal secretions, and if symptoms develop they are usually related to infections in these areas.