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Autosomal dominant transmission describes how a defective gene on one of the 22 autosomes, i.e. the non-sex chromosomes, passes on the disease. Only one of the parents will have the condition caused by the abnormal gene. Each affected individual has a 50% risk of transmitting the disease to his or her children.

 

Autosomal recessive transmission means that both genes on the chromosomes of one pair are defective. Such diseases are very rare. The inherited defected gene then comes from both parents. In such cases, the parents are very often asymptomatic carriers of the disease. The risk of two parents carrying the defective gene, to transmit the disease to their child is only 25%.

 

 

Heredity

Men and women encounter the same risk of acquiring VWD. The predisposition of the disease is located on a chromosome that is inherited identically by both girls and boys. The disease can also develop as a result of mutation or alteration of the genotype without either of the parents being carriers.

With the exception of type 3 VWD, which is rare and severe, and cases of type 2N VWD, VWD is generally inherited by autosomal dominant transmission. Autosomal dominant transmission occurs when there is an abnormal gene on one of the chromosomes among the 22 pairs of autosomes, or non-sex (X or Y) chromosomes. Since the condition is dominant, as opposed to recessive, only one of the parents will have the condition caused by the abnormal gene.

Type 3 VWD and cases of type 2N VWD are inherited by autosomal recessive transmission. Autosomal recessive transmission occurs when there is an abnormal gene on both chromosomes in a pair of the 22 pairs of autosomes. For an individual to be affected, he or she has to inherit the abnormal gene from both parents. The affected individual has no normal gene and consequently has a much more severe form of the disease than someone with only one abnormal gene.

Page updated: 2016-06-17