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Children inherit many
characteristics from their parents, such as the colour of
their eyes and hair colour, and their height and build.
Sometimes, a child can inherit a health condition. This
happens when a gene changes (mutates) and is passed down
through a family. Each generation of children can inherit
the gene that causes the condition. A baby can inherit
defective genes from one or both of its parents.
Most inherited conditions are quite rare, affecting one
person in every several thousands or millions of people.
Inherited conditions
There are more than 6,000 known single-gene inherited
conditions. Single gene means that the condition is caused
by changes (mutations) that occur in the DNA of one gene.
Some conditions can be inherited from just one parent,
such as Huntington's disease and Marfan syndrome. Most
inherited conditions cannot occur unless both the mother and
father pass on the defective gene; these include cystic
fibrosis, sickle cell anaemia, spinal muscular atrophy and
Tay-Sachs disease.
Inherited conditions can happen unexpectedly. Both
parents can be healthy and unknowingly carry a defective
gene, which can be passed on to their baby, meaning the baby
can be born with the inherited condition.
There are some genetic conditions, such as Down's
syndrome, that are usually not inherited. These generally
result from a change in cells (mutation) when the cells
divide in the earliest stages of pregnancy.
Getting advice
If you know that an inherited condition runs in your
family, it's a good idea to seek advice before you try for a
baby. Your GP can offer advice about the risks of you
passing on the condition. Depending on the type of
condition, your GP may recommend that you see a specialist
for further testing or help, such as genetic testing or
genetic counselling.
If you're already pregnant, your GP can give you advice
about antenatal screening, for example, where there is a
strong family history of conditions such as muscular
dystrophy, spina bifida or congenital heart defects.
Your GP may ask you for a complete family medical
history. If you don't already know, you will need to find
out as much information as you can. For each family member,
write down:
- their sex,
- their date of birth,
- their ethnic origin,
- the dates of any medical problems,
- the diagnosis, and
- if appropriate, the cause and date of their death.
Ideally, the information you give your GP should cover
your brothers and sisters (if you have any), your parents,
uncles, aunts and cousins. You GP may also ask you about:
- any miscarriages,
- children in your family who have died, and
- half-brothers and sisters.
If a hereditary condition runs in your partner's family,
you will need to find out this information about his family
too. |
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