When someone finds out that they or one of their children has CGD, one of the first things they may wonder is how likely people with CGD are to have children, or subsequent children, with the condition.
Both men and women can pass the condition on to their children. The chance of a child of a CGD parent developing CGD varies considerably with the type of CGD involved – X-linked or autosomal recessive.
It is also dependent upon whether the other parent has any genetic links with CGD (in other words, if they themselves have the condition or are a carrier.
X-linked CGD and having children
Non-carrier mother/carrier father: they can produce daughters who are carriers but don’t have CGD itself, and sons who are neither carriers nor have CGD (their X chromosome will have come from their ‘healthy’ mother).
Carrier mother/non-carrier father: they can produce girls who are either healthy or carriers, and boys who are either healthy or have CGD itself.
Carrier mother/carrier father: the girl children will be carriers and statistically half of all boy children will have CGD.
Autosomal recessive CGD and having children
It would be extremely unlikely that an individual with autosomal recessive CGD would go on to have a child with CGD. However, all the children of individuals with autosomal recessive CGD would be carriers of CGD but not affected by the condition.
However, a carrier could have a child with CGD if their partner carried the same genetic defect which would, again, be very unlikely indeed – and also very unlucky.
A carrier mother and a carrier father have a one in four chance of having a child affected by CGD, a one in four chance of having an unaffected child and a two in four chance of having children who will be carriers.
Help with making a decision
Blood tests and a family history can be used to estimate the likelihood that a child will inherit CGD. CGD patients and families may find that a hospital genetic counselling service can offer valuable guidance and advice on family issues. Testing can also be offered prenatally. Chorionic villus sampling (CVS) or fluid from the womb (amniocentesis) from the womb during early pregnancy can show whether the baby will have CGD.
A technique called Pre-Implantation Gender Determination (PIGD), which involves using IVF (in vitro fertilisation) treatment, can be used to enable couples to choose the sex of their baby, which may be crucial especially in cases of X-linked CGD.
Pregnancy and CGD
Women with CGD can become pregnant and have babies without adverse effects to their health. Some of the drugs used to treat infections common in CGD patients may cause birth defects or miscarriage so suitable alternatives that are safe to use during pregnancy are given instead.
Women with CGD who are planning a pregnancy should discuss it with their doctor prior to becoming pregnant so that plans for alternative medication can be made and women can be sure they are in optimum health.
If this isn’t possible, women should inform their doctor as soon as they know they are pregnant. The temptation may be to stop taking preventative medication but this could place both them and their baby at risk. Any potential infection and the treatment it may entail is potentially more harmful than taking appropriate preventative medication.