A 44-year old patient with mild haemophilia A (FVIII activity 6%, missense mutation in exon 26, c.6977G>A, p.Arg2326Gln) with arterial hypertension, obstructive sleep apnoea and morbid obesity (body weight 130 kg, body mass index 45 kg/m2), previously treated episodically with octocog alfa, was admitted to the emergency department due to severe respiratory failure. This evidence concerns the gene F8 and hemophilia A.