The Cancer Genetics Clinic is part of Stanford's
Cancer Center, a National Cancer Institute-designated center
offering genetic counseling and testing for individuals concerned with
the risk of an inherited cancer predisposition. The clinic staff
includes medical oncologists, genetic counselors, and geneticists.
Genes are the blueprints for making the substances, called proteins,
our bodies need to develop and work properly. Most genes come in
pairs, one of which is inherited from the mother and the other from
the father. A mutation is a change in a gene that prevents it from
working properly. Mutations in genes are inherited from our biological
parents in specific ways. One of the basic patterns of inheritance of
mutations is called autosomal dominant inheritance.
What is autosomal dominant inheritance?
Autosomal dominant inheritance means that the gene carrying a
mutation is located on one of the autosomes (chromosome pairs 1
through 22). This means that males and females are equally likely to
inherit the mutation. "Dominant" means that having a
mutation in just one of the two copies of a particular gene is all it
takes for a person to have a trait, such as an increased risk of
developing cancer (see explanation below on "variable
expressivity" and "reduced penetrance"). When a parent
has a dominant gene mutation, there is a 50 percent chance that any
child he/she has will also inherit the mutation.
There are four possible combinations in the children. Two of the
four, or 50 percent, have inherited the mutation. The other 50 percent
have not inherited the mutation. These four combinations are possible
every time a pregnancy occurs between these two individuals. The
gender of the children (whether they are sons or daughters) does not
matter. The chance is 50/50 for each pregnancy.
An important characteristic of dominant gene mutations is that they
can have variable expression. This means that some people have milder
or more severe symptoms than others. In addition, which systems of the
body the mutation affects can vary as can the age at which the disease
starts, even in the same family. Another important characteristic of
dominant gene mutations is that in some cases, they can have reduced
penetrance. This means that sometimes a person can have a dominant
mutation but not show any signs of disease. The concept of reduced
penetrance is particularly important in the case of autosomal dominant
cancer susceptibility genes. If a person has inherited a cancer
susceptibility gene, it does not mean they will automatically develop
cancer. It simply means that they have inherited a mutation in a gene
that gives them a higher chance to develop cancer than the general
population (i.e., someone without the mutation).
Most families know that there is a dominant trait or disorder in
their family, because it is passed from parent to child and can be
seen in many generations. When a cancer susceptibility gene mutation
is inherited in an autosomal dominant manner, it means that the
mutation can be inherited from the mother, or the father, who
themselves may or may not have ever had any type of cancer. However,
with autosomal dominant inheritance, if a parent does not have the
gene mutation associated with cancer risk in the family, he/she cannot
pass it on his/her children.
James Ford, MD, director of the Stanford Cancer Genetics Program, has always been fascinated with figuring out how genetics influences cancer. His interest is in working with families to lower their risk of familial cancer.
This video explains how genetic counselors at Stanford’s Cancer Genetics Clinic help families understand if they have a hereditary cancer syndrome and an elevated risk for colon cancer.
Clinical trials are research studies that evaluate a new medical approach, device, drug, or other treatment. As a Stanford Health Care patient, you may have access to the latest, advanced clinical trials.
Open trials refer to studies currently accepting participants. Closed trials are not currently enrolling, but may open in the future.
See the BRCA
Decision Tool which guides the management of cancer risks for
BRCA1 and BRCA2 mutation carriers.
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coordinator. The medical release form is an authorization form for
external facilities to release medical records to Stanford Health Care
(formerly Stanford Hospital & Clinics).
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provides comprehensive services to refer and track patients, as well
as provides the latest information and news for physicians and office
staff. For help with all referral needs and questions visit Referring Physicians.
HOW TO REFER
Fax a referral form with supporting documentation to 650-320-9443.
Please note, though this form is from Stanford Health Care (formerly
Stanford Hospital & Clinics), it is also used for all Cancer
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