Inheritance pattern
VWD is usually an inherited condition that is caused by a gene alteration. This means it is passed down through the genes from parent to child. The affected gene is on one of the regular chromosomes, not on one of the sex chromosomes (like haemophilia). So, unlike haemophilia which usually affects only males, VWD affects males and females equally.The VW gene is usually dominant, meaning that a parent who has VWD has a one in two (50%) chance of passing a VW gene on to each of his or her children. This is called the classic inheritance pattern, and Types 1 and 2 are usually inherited in this way, although the inheritance of Type 1 does not always follow this pattern and can be difficult to predict. This is an active area of medical research.
Many people who carry the gene are actually asymptomatic which means that they do not have bleeding symptoms themselves, however they can still pass the condition on to their children, who could have more severe bleeding symptoms than their parents.
In the less common inheritance pattern, two parents, both carrying the gene but not necessarily experiencing symptoms, may together have a child who is severely affected by VWD. This is called the recessive inheritance pattern, and Type 3 VWD is usually inherited in this way. If both parents carry the VW gene, they have a 25% chance of having an unaffected child, a 50% chance of having a child who is mildly or moderately affected and a 25% chance of having a child who is severely affected with Type 3 VWD.
Different members of the same family can be affected more or less severely than others. This means that some people may be unaware that they have the affected gene, and the doctor should to test other family members, even if they have never had any bleeding symptoms. Sometimes people who are asymptomatic are diagnosed in this way.
When there is no family history
Sometimes, VWD is not inherited. Some children have the condition because there was a mutation, or change in the gene before or during conception. When this happens, their chances of passing the condition on to their children are the same as those of any parent who has inherited the condition, whether or not they have bleeding symptoms themselves.Very rarely VWD can develop later in life. This is known as acquired VWD. This is usually caused by the body developing antibodies to its own VWF, which can stop it from working. Someone who develops acquired VWD will often already have a serious immune system problem such as rheumatoid arthritis, systemic lupus erythmatosis or certain types of cancer.
Symptoms
Some people with the affected gene may not have any bleeding symptoms. Others may bleed for longer than usual. VWD is often characterised by bleeding from the mucous membrane, which is the visible pink tissue which lines the cavities in the body, such as the mouth, gums and nose.Women affected by VWD may have the following symptoms:
- Heavy or prolonged menstrual bleeding
- Frequent nosebleeds, which may be severe
- Easy bruising
- Prolonged bleeding after childbirth
- Prolonged bleeding after surgery or having a tooth removed
(published with permission in writing from:http://www.womenbleedtoo.org.uk)


