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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 Page 1 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 Page 2 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 Page 3 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. Page 4