Inherited Disorders
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Inherited disorders
Inherited disorders are caused by faulty genetic material
that is passed on to future generations. They are sometimes
called genetic disorders.
One example of an inherited disorder
is polydactyly, where someone has
extra fingers or toes. This disorder is
caused by a dominant allele.
This means that polydactyly can be
passed on, even if only one parent
has the disorder.
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Cystic fibrosis
Cystic fibrosis is an inherited disorder that affects the
cell membranes. Over 8,500 people in the UK have
cystic fibrosis.
Cystic fibrosis primarily affects
the digestive and the
respiratory systems. As a
result, sufferers find it difficult
to breathe and to digest food
as their internal organs are
clogged by a thick mucus.
Cystic fibrosis is caused by a recessive allele. This means that
the disorder can be passed on by two parents who are
carriers, but who do not actually have the disorder themselves.
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Cystic fibrosis
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Diagnosing inherited disorders
Cystic fibrosis in children is usually diagnosed
with a sweat test. However, if a couple has a
family history of cystic fibrosis, or another
inherited disorder, they may want to
screen their unborn child for the
alleles that cause the disorder.
There are two types of test:
 amniocentesis – fetal cells are
collected from the amniotic
fluid via a hollow needle
 chorionic villus sampling – fetal cells are collected from
the chorionic villi in the placenta with a suction tube.
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Fetal testing
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Genetic screening
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Regulating difficult decisions
The Human Fertilisation and Embryology Authority (HFEA)
is the independent body in the UK responsible for overseeing
the use of embryos in fertility treatment and research.
The HFEA decides which
embryo research and embryo
selection should be allowed.
Science is advancing
quickly, so the HFEA will
increasingly have to make
decisions about the ethics of
new treatment and research.
If something can be done, does that mean it should be?
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Glossary
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Multiple-choice quiz
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