Page 14 - HFA_Dateline_2020_Q4_Winter

WHAT CAUSES
GENETIC
CONDITIONS?

PROVIDED BY AND PRINTED
WITH PERMISSION BY BIOMARIN

Did you know there are
approximately 20,000 genes in
the human genome?

A mutation or permanent variation, in just one gene can lead to a genetic
condition. Knowing what causes a genetic condition is the first step in
understanding how ongoing research in gene therapy might enable physicians
to treat these conditions differently. No gene therapies for hemophilia A or B
have been approved for use or determined to be safe or effective.

Genetic Conditions Are the
Result of Mutations

Genetic conditions are the result of mutations, or variations, in the make-up of
a gene. These mutations are most often passed down from biological parents
but can sometimes happen spontaneously. Cystic fibrosis and hemophilia are
examples of genetic conditions.

In hemophilia A, the gene responsible for producing factor VIII is mutated. This
gene is located in the X chromosome. Males have only one X chromosome,
which means that one copy of the mutated gene is enough to cause
hemophilia, making it more common in this population.

While it is possible for females to have hemophilia, it is rare for them to
present with symptoms of the disease because the disease affects just one
X chromosome. Since females have 2 X chromosomes, both chromosomes
would need to have a mutation for them to be severely affected by the disease.
However, females who do not show signs of hemophilia are often referred to
as “carriers” because they can still pass on the mutated gene to their children,
even though they have no symptoms of the condition.

14 DATELINE FEDERATION < www.hemophiliafed.org