Download Researching Your Health History

Helen V. Smith
Researcher, Author and Speaker
Email: [email protected] Twitter: @HVSresearch
Blog: http://helenvsmithresearch.blogspot.com/
ABN 53 785 967 121
Researching Your Health History
The information provided is for general interest and is no substitute for medical advice.
Everybody has a family history and as genealogists, we spend our time researching for further
facts and stories. We all also have a health history within our family. We document this from the
same resources we use to document our family history with just a few caveats. The cause of
death on death certificates varies in accuracy the further back in time we go. Prior to the 1900s
the medical profession was still learning about germ theory and often the cause of death given
was actually the symptoms observed rather than the cause. Also the study of genetics and
genetic illnesses was not understood so if by chance you have a family member with a rare
genetic illness you are not going to get the accurate cause of illness/death on the certificate.
As we look at our family tree we see that great-grandfather had a stroke at age 65 and died of a
heart attack at age 87. His wife was diagnosed with type 2 diabetes at age 60 and died of
congestive cardiac failure at age 71. She had been overweight for many years and had also
smoked a packet a day for over 40 years.
By researching your family health history it helps you learn more about your or your children’s
risk for health problems. It can also guide your doctor in determining what screening tests
should become part of your health care schedule. It can also let you know of risk factors that
you may be able to change because you knew of a potential health condition.
There is a family health history risk triangle. Certainly there is a genetic component but more
often it is multifactorial and the environment in which you live and the behavioural choices you
make can also play a significant role in your health risks. Health risk factors are actions that can
increase your chances of being diagnosed with a health condition eg smoking is a known risk
factor for lung cancer.
Environmental and occupational risk factors can include exposure to chemicals, working
conditions such as coal miners because of their exposure to the coal dust were at a risk for
pneumoconiosis (black lung disease). Behavioural risk factors include a poor diet, lack of
physical activity, being overweight, smoking and not having regular medical check-ups.
Genetics: genes are the instructions for telling our bodies how they should operate. They are
passed down from parents to their children. Sometimes due to mutations or changes these may
not operate the same and can pose a risk to health.
You can inherit a gene change that increases your risk for disease for example cystic fibrosis.
Many diseases such as type 2 diabetes are caused by a combination of lifestyle, environment
and potentially also sometimes gene changes.
We collect the family health history data using the same tools and resources we use for family
history. Death certificates, talking to family members, medical records if we have them,
occupations, military records etc.
© Helen V Smith
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So what information to collect. Ideally you should look at a minimum of three generations back
in time and any you have forward of blood relatives only. While the spouses of your blood
relations are still family they don’t have an impact on your health history.
You would look for any major health conditions, at what age did the family member develop the
disease, was it a chronic disease or was it fatal, what was the ethnic background as there are
some conditions which are more common in some ethnic groups. Was there cancer in the
family and if so what type of cancer and at what age was it diagnosed? (certainly due to changes
and improvements in diagnostic tests and access to tests the age of diagnosis sometimes has to
be taken with caution). Were there any fertility issues such as the inability to have children or
maybe miscarriages or did the women develop gestational diabetes, or have longer periods of
morning sickness. Were there any lifestyle factors of the individual such as smoking, drinking,
addictive behaviour, depression etc.
At what age did they die. If you look at your family chart and everybody is living a long healthy
life that is good news.
Cancer
Many families nowadays know of at least one member with cancer. Some families have a
number of members with cancer and for some the feeling is that “cancer runs in our family”. In
these cases it is possible the cancer could be hereditary caused by a gene mutation. This is more
likely if the people were diagnosed with the cancer before the age of 40.
For the families so affected you can see multiple people affected who have a blood relationship
(potentially if you have members in a community affected but no blood relationship it may be
caused by environmental conditions such as community exposure to herbicides). For those with
the blood relationship you would also expect to see more than one generation affected, the
cancers appearing before the age of 50 and more usually 40, sometimes more than one type of
cancer in an individual or repeated cases of cancer in an individual. Breast cancer occurring in
men in a family would also be a potential indicator of a genetic condition.
Draw the diagram generally use boxes for men and circles for women and draw a drop down
pedigree chart, a straight line between indicates a sexual relationship (marriage/de facto). Add
in all children by age (including any miscarriages) For those without children was this by choice
or the inability to have children? Keep the members of the same generation on the same line
for easy analysis. Cross a line through if a person is deceased and write the age and cause of
death. Colouring the boxes/circles for known conditions can also make it easier to analyse. This
drawing is known as a genogram.
© Helen V Smith
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If the person has died of other causes state this too eg car accident, soldier in war as it is
possible if they had lived longer they may have become ill. Whatever symbols or colours you
use to show a disease/condition make a legend which explains it as down the track you may not
remember that blue was for cancer and green for heart attack.
Angelina Jolie is a strong example of someone who looked at her family’s health risks and made
a decision based on what she found. Her great-grandmother died at age 53y of ovarian cancer,
her grandmother died at 45y with cancer, her mother died at age 56y of ovarian cancer, her
aunt is currently in stage 4 terminal breast cancer. The family has the BRAC1 gene mutation. (it
is known that breast and ovarian cancer can be caused by the same gene mutation).
Certainly you can draw the trees by hand but if you really want to use a computer program
there is Genopro at http://www.genopro.com
Another caveat: just because one person has a serious disease at an early age does not
necessarily mean a hereditary generic link. I was diagnosed at age 40 with breast cancer and
there is no history of it in my family.
Another famous case is Queen Victoria who had no history of haemophilia in the family but a
chance gene mutation occurred and it had a severe effect on the royal families of Europe as a
result. Due tt he fact that cells in your body are constantly being renewed there are chances for
a random gene mutation. In the greater majority of cases even if a change occurs it has no effect
on life but sometimes it does.
You can also use this genographic technique to map non-life threatening conditions such as
height, hair colour, deafness, musical ability etc.
If a genetic condition does occur there are a number of ways it can be inherited. A human has
22 pairs of chromosomes and a pair of sex chromosomes (XX for women and XY for males).
If you had a single gene autosomal dominant
inheritance such as shown on the left the features
you would see would include:
 people with the condition in each generation
 males and females affected in roughly equal
proportions
 all forms of transmission present (male to
female, male to male, female to male and
female to female).
 At conception, each child has a 1 in 2 (50%) chance of inheriting the condition.
Examples of autosomal dominant conditions include: Huntington disease, Familial
hypercholesterolaemia, Marfan syndrome and Myotonic dystrophy.
© Helen V Smith
Single gene autosomal recessive
Features you would see on the chart would
include:
 males and females have the condition in
roughly equal proportions
 consanguinity, where both parents have
one or more ancestors in common
(collapsed pedigree), increases the chance
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

that a condition presenting in a child of theirs might be due to both parents being
carriers for the same recessive gene alteration
At conception each child of parents who are both carriers has a:
 1 in 4 (25%) chance of being an unaffected non-carrier;
 a 2 in 4 (50%) chance of being a carrier
 a 1 in 4 (25%) chance of inheriting the condition
Examples of autosomal recessive conditions include:
 Cystic fibrosis
 Sickle-cell anaemia
Single gene inheritance X chromosome linked
Remember males are XY and females XX. Men inherit their X gene from their mother and the Y
gene from their father and so only have one copy of the X gene. If it is affected the male will
have the condition, whereas the female because she has two X genes is more likely to be a
carrier and not affected as she is likely to have a non-affected X gene. Males transmit their Y
chromosome to their sons so sons cannot inherit an X-linked recessive condition from their
father but girls can inherit it from their father.
Features of X-linked recessive inheritance that you may see on a family tree include:
 males affected almost exclusively
 the gene alteration can be transmitted from female carriers to sons
 affected males cannot transmit the condition to their sons
Examples of X-linked recessive conditions include: Haemophilia and Duchenne muscular
dystrophy.
Mitochondrial Inheritance
The pattern of inheritance associated with alterations in the mtDNA involves both males and
females, but always with the condition passed on through the female line (maternal
inheritance). Since many mitochondria are passed into the egg from the cells in the ovary, all
the offspring of an affected woman would be expected to inherit the condition. An affected male
does not pass his mitochondria on to his children, so his children will be unaffected by the
condition.
It is because of the different types of inheritance
of genetic conditions that it is important for risk
analysis in the event that a genetic condition does
exist in your family that medical advice and
potentially genetic counselling is sought to
alleviate concerns.
© Helen V Smith
It is worthwhile to chart your health history and if
you have any concerns SEE a doctor, discuss your
concerns, have any recommended tests.
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