Complex sentence: Unlike individuals with Haemophilia A and B, patients affected by haemophilia C are not ones to bleed spontaneously--haemorrhages tend to happen after a major surgery or injury.
Split into simpler sentences: Unlike individuals with Haemophilia A and B, patients affected by haemophilia C are not ones to bleed spontaneously. In these cases, haemorrhages tend to happen after a major surgery or injury.