Hereditary Breast and Ovarian Cancer Awareness week

Although not typically a thing in Australia yet, in the United States, the month of September is ovarian cancer awareness month and October is breast cancer awareness month. The week in between these months has become the hereditary breast and ovarian cancer (HBOC) awareness week. The aim of HBOC awareness week is to raise awareness of hereditary breast and ovarian cancer and other related cancers. It also increases awareness of people with either a strong family history of these types of cancers or people or families with a genetic predisposition to breast and ovarian cancer, for example, having a gene change or mutation in BRCA1 or BRCA2 or other related genes. People with a gene change predisposing to cancer but who have not had cancer themselves are sometimes referred to as previvors as opposed to the cancer survivors who have had cancer.

Different support groups are conducting various events to mark the week. One such group is called FORCE and the link is below.

http://www.facingourrisk.org/get-involved/events/special-event.php

I have recorded a podcast, which will become live during this week to help raise awareness. I have three fantastic guests. They are Ellen Matlof from My Gene Counsel who is a certified genetic counselor in the USA. My second guest is a lady called Nicole who has recently found out that she has a BRCA2 mutation. She hasn’t had cancer herself but has a family history of cancer. My third guest is Krystal Barter who is the founder of Pink Hope and she has a BRCA1 mutation.

For more information about genetic counselling and testing for a predisposition to cancer, please see the following links:

https://rarediseases.org/rare-diseases/hereditary-breast-ovarian-cancer-syndrome/

http://www.genetics.edu.au/publications-and-resources/facts-sheets/fact-sheet-32-breast-and-ovarian-cancer-and-inherited-predisposition

Lift for Li Fraumeni syndrome #Lift4LFS

Last week I was lucky enough to attend a conference called the “Familial Aspects of Cancer Research + Practice”. This annual conference is arranged by the Kathleen Cunningham Foundation Consortium for Research into Familial Breast Cancer or kconfab for short. It is attended by scientists working in familial cancer from all over Australasia and the world and is also attended by genetic counsellors and doctors as well. There are presentations about many different aspects of cancer that runs through the family, but my favourite talk this year was by the Li Fraumeni association of Australasia.

Li Fraumeni syndrome (LFS) is a genetic condition where people with a gene change (mutation) in a gene called tp53 live with a high predisposition to developing cancer. People have a 50% chance of developing their first cancer by the age of 50 and up to a 100% chance of having cancer by the age of 80. LFS follows what is known as an autosomal dominant meaning that when a person with LFS has a child, there is a 50% or 1 in 2 chance of passing this changed gene on. The tp53 is often referred to as the “guardian” of the genome meaning that when there is a mistake or fault in this gene, it can have a devastating effect on the body.

The Li – Fraumeni Syndrome Association (LFSA) was created in the USA in 2010 as a way of providing and facilitating advocacy, support and information for those affected by LFS. The Australia and New Zealand chapter of the Li – Fraumeni Syndrome Association has recently launched. The mission of the LSFA is to bring together medical practitioners, researchers and scientists, patients and caregivers to further good research and care of individuals and families with LFS. Check out their video on youtube!

www.lfsassociation.org

www.kconfab.org

#lift4LFS

 

Factsheet:

https://rarediseases.org/rare-diseases/li-fraumeni-syndrome/

Resources:

http://www.geneticalliance.org.au/conditions_detail.php?Li-Fraumeni-syndrome-322

LFS video

https://www.youtube.com/watch?v=Bh3otLnixyg

Reciprocal Translocations

A translocation is the term used to describe a rearrangement of chromosome material between two or more chromosomes. There are two main types of translocations; reciprocal and Robertsonian translocations. In this blog piece, I will discuss reciprocal translocations.

In each of our body cells (excluding our egg or sperm cells) inside the nucleus we have 23 pairs of chromosomes. They are numbered 1 to 22 in descending order of size and the remaining pair of chromosomes are our sex chromosomes; XX for females and XY for males. A reciprocal translocation is where part of one chromosome breaks and exchanges with part of another chromosome, which has also broken off. Said another way, two chromosomes break and these broken pieces swap and join back together. When no genetic material is lost, this is said to be a balanced reciprocal translocation. Reciprocal translocations can involve any of the chromosomes.

Carriers of a balanced reciprocal translocation may not even be aware that they are carrying a chromosomal anomaly. Depending on the location of the break, if no interruption of the genetic information in the DNA code occurs, a carrier of a balanced translocation will have no symptoms and will not affect their development or health. However occasionally where the chromosomes break, if this is in the middle of an important gene, for example, the person may have some associated health issues. Most translocations are spontaneous, meaning, they occurred in the egg or the sperm that went on to create a person. However sometimes translocations can be inherited.

Balanced reciprocal translocation carriers are at risk of having chromosomes in their eggs or sperm with genetic material gained or lost and this could result in a pregnancy that has an unbalanced reciprocal translocation. Having extra or missing bits of chromosome can cause a wide variety of health problems including mild to severe health problems and developmental delay.

If someone is at risk of being a carrier of a balanced reciprocal translocation, they can have a genetic test examining their chromosomes. This test is called a karyotype and the scientists in the laboratory will be able to see if and where a translocation has occurred. A more detailed chromosome test called a microarray may also be ordered to see exactly where the breakpoints are and to see if any genetic material has been added or lost.

When a partner in a couple has a balanced translocation they may experience infertility or recurrent miscarriages. In some cases it may be possible to have Non Invasive Prenatal Testing (NIPT), which is a blood test on the pregnant mother from 10 weeks gestation, to see if the pregnancy has a translocation. In some cases NIPT is not possible. If this is the case, an invasive test during the pregnancy such as a chorionic villus sampling (CVS) or amniocentesis may be performed to examine the baby’s chromosomes.

Couples presenting for genetic counselling due to a reciprocal translocation can be challenging from a psychosocial point of view as well. Having long periods of infertility or miscarriage after miscarriage can be very taxing on couples. IVF is one technique that couples can utilize to increase their chances of having a baby. Other options would include donor egg, sperm or embryos or adoption.
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Genetic Condition – HFE – Hereditary Haemochromatosis

Genetic Condition – HFE – Hereditary Haemochromatosis

HFE – Hereditary Haemochromatosis is a common genetic condition in which sufferers have an abnormally high level of iron uptake into various organs in their body. It is an iron overload disorder. HFE – Hereditary Haemochromatosis was also known as Bronze diabetes in the past due to the colour that an affected person may turn without treatment. Early symptoms include weakness, fatigue, abdominal pain and weight loss. If left untreated, HFE – Hereditary Haemochromatosis can lead to skin discolouration, diabetes and heart problems.

 

Inheritance / genetic counselling

HFE – Hereditary Haemochromatosis follows an autosomal recessive pattern of inheritance. A personal affected with this condition has two faulty copies of their HFE gene; one inherited from their mother and the other from their father. If an affected person’s parents had one working copy of HFE and one copy with a mutation, they are referred to as being a carrier of HFE – Hereditary Haemochromatosis. A person with HFE – Hereditary Haemochromatosis can only pass on a faulty copy of the HFE gene meaning that all of their children will either be carriers if they inherit a working copy of the HFE gene from their other parent or at risk of developing the condition if they inherit a faulty copy of the HFE gene from each parent. Siblings of a person with HFE – Hereditary Haemochromatosis usually have a 25% risk of also having the condition, however if their parent also has the condition then 50% of their children are at risk.

 

Molecular genetics

This condition is due to a mutation in the HFE gene, which is located on the short arm of chromosome 6 at location 6p22.2. A gene is made of DNA and DNA is made of four chemicals referred to as bases (A, G, C & T). These bases combine together in a pattern to code for one of 20 amino acids. Amino acids strung together form a protein. There are three common mutations in the HFE gene; C282Y, H63D and S65C.

About 60 – 90% of people with two copies of the C282Y mutation will develop iron overload in their lifetime, whereas only about 5% of people with a C282Y and H63D combination will develop the condition. About 1% of people with two copies of H63D will go onto having iron overload.

 

Prevalence

HFE – Hereditary Haemochromatosis is the most common genetic condition in Australia and one of the most common genetic conditions in Caucasians. HFE – Hereditary Haemochromatosis is uncommon in people with African and Asian decent. HFE – Hereditary Haemochromatosis is more common in men than women.

 

Management

The most common treatment for HFE – Hereditary Haemochromatosis is blood letting to reduce iron levels in the blood.

 

Differential diagnoses

Not everyone with iron overload will have HFE – Hereditary Haemochromatosis. Other types of Hereditary Haemochromotosis include Juvenile hereditary haemochromotosis (also known as hereditary haemochromotosis type 2) and TFR2 – Hereditary Haemochromatosis.

 

Resources:

http://www.americanhs.org/

www.haemochromatosis.org.au

www.haemochromatosis.org.uk

http://www.genetics.edu.au/publications-and-resources/facts-sheets/fact-sheet-47-hereditary-haemochromatosis