Most of our physical characteristics, including our susceptibility to certain diseases, are determined by genetic material called DNA. DNA is found in the nucleus of cells, organized into 46 units called chromosomes, arranged in 23 pairs. Sperm and egg cells contain only one chromosome from each pair. Each chromosome holds hundreds of genes carrying chemical codes that affect our development. Alterations of genetic material may result in a child inheriting a disease or a predisposition to develop one.
Your health profile
The genes you inherit influence your risk of disease. Some inherited disorders are evident at birth; others develop later.
If you have inherited fair skin, you will be particularly vulnerable to the effects of sunlight and may be at increased risk of developing skin cancer.
You may be more likely to develop heart or blood vessel disorders during adulthood if one or both of your parents has a similar disorder.
Some disorders of the digestive system, such as certain types of colorectal cancer, sometimes run in families.
Many joint disorders, such as osteoarthritis and rheumatoid arthritis, have an inherited element, but do not usually develop until adulthood.
You are more likely to develop an allergic breathing disorder, such as asthma, if either of your parents has asthma, hay fever, or eczema.
Some blood disorders are inherited. These include thalassaemia, which affects the ability of red blood cells to carry oxygen, and haemophilia, which affects blood clotting.