Can genetic diseases be passed from children to their parents?

The scientist inside of me was trying to break out, so here's the article I wrote for the school science magazine this year. You could even count it as revision...

Traditionally, it is thought that genetic diseases are passed from parents to children as offspring receive half of each of their parent’s DNA. However, recent studies have shown that some diseases are transmitted from a child to their mother.

When a foetus is developing in the womb, cells are constantly exchanged from the foetus to the mother via the placenta. For most women, these cells are removed by the immune system shortly after the birth of the baby. In a small proportion of women these cells stay in the body for decades and are incorporated into tissues such as in the brain and skin, in a process called microchimerism.

Mothers who had a low genetic risk of rheumatoid arthritis, where joints become swollen and painful, but went onto develop the condition were found to be likely to show microchimerism. There are two theories to suggest how foetal cells cause arthritis in the mother…

1) The maternal immune system reacts to the foetal cells in an attempt to remove them from the body. As the cells are part of the woman’s tissues the body begins to attack itself, this causes inflammation in the joints.

2) Foetal cells that are stowed in the body attack the mother’s immune system, causing inflammation and joint pain.

For women with an autoimmune disease, where the body’s immune system turns against itself, the development of arthritis from a microchimerism was common. This is because the mother’s body is unable to protect itself from the foetal cells carrying the disease inherited from the father.

Other diseases that microchimerism is thought to cause are:

·       Type 1 diabetes- where the pancreas doesn’t produce any insulin so the blood sugar levels stay constantly high.

·       Scleroderma- a disease of the connective tissue causing hardening of skin and blood vessels.

·       Primary biliary cirrhosis- a liver disease where bile ducts become damaged and the build-up of bile in the liver causes scarring.

It is currently thought that only a small percentage of genetic diseases are caused by microchimerism and that foetal cells have many benefits, such as repairing damage in the mother’s heart during pregnancy. Lots more research is needed to find out exactly what’s happening and why.


Have a beautiful day x
 

References:

http://www.newscientist.com/article/dn26408-fetuss-arthritis-genes-can-affect-the-mother.html#.VMaeyy6YjsQ

http://www.nhs.uk/conditions/Primary-biliary-cirrhosis/Pages/Introduction.aspx

http://www.sclerodermasociety.co.uk/