Database: thrombosis_prediction
Question: Among the patients whose total cholesterol is within the normal range, how many of them have a P pattern observed in the sheet of ANA examination?
SQL: SELECT COUNT(T1.ID) FROM Patient AS T1 INNER JOIN Laboratory AS T2 ON T1.ID = T2.ID INNER JOIN Examination AS T3 ON T1.ID = T3.ID WHERE T3.`ANA Pattern` = 'P' AND T2.`T-CHO` < 250