BAG3 and Respiratory insufficiency: BAG-3 p.Pro209Leu (c.626C > T) mutation-induced MFM subtype VI is quite rare clinically, with only 19 patients reported at present, of whom 17 patients already had respiratory insufficiency at the time of report, and most required mechanical ventilation support.[2–13] However, these patients generally did not undergo further evaluation of their respiratory function.