Database: thrombosis_prediction
Question: How many patients with a normal Ig A level came to the hospital after 1990/1/1?
SQL: SELECT COUNT(T1.ID) FROM Patient AS T1 INNER JOIN Laboratory AS T2 ON T1.ID = T2.ID WHERE T2.IGA BETWEEN 80 AND 500 AND  strftime('%Y',  T1.`First Date`) > '1990'