People are born with an inherited bleeding disorder. They cannot catch it from someone like a cold. A bleeding disorder is usually passed down from parent to child at conception. The disorder is caused by an abnormal gene. Genes carry messages about the way the body’s cells will develop as a baby grows into an adult. They determine a person’s hair and eye colour, for example. Sometimes a bleeding disorder can occur when there is no family history of it. This is called a spontaneous mutation. It was caused by a change in the person’s own genes.
All types of VWD are inherited in an autosomal pattern. This means that men and women are affected in equal numbers. (See Heredity of von Willebrand disease).
Platelet function disorders have variable inheritance patterns. Some follow an autosomal recessive pattern of inheritance. This means that both parents need to carry the defective gene for the child to be affected. Others follow an autosomal dominant pattern, meaning only one of the parents needs to carry the gene for it to be passed on to the child. Platelet function disorders affect men and women in equal numbers.