Background
Galactosaemia literally means ‘galactose in the blood’. Galactose is a sugar which mainly comes from lactose, the sugar found in milks. Lactose is normally broken down into the two simple sugars, galactose and glucose. The galactose is then broken down further and used in many parts of the body including the brain. In galactosaemia it cannot be broken down completely and used because of deficiency or absence of an enzyme, galactose-1-phosphate uridyl transferase or Gal-1-PUT. Galactose, galactose-1-phosphate and other harmful chemicals build up and lead to the serious illness that occurs in the first few weeks of life once the baby is fed on milk containing lactose. It is a lifelong condition.

What Causes Galactosaemia?
The enzyme is deficient or absent because of a mistake or mutation in the genetic code, the DNA.  Our chromosomes are made of DNA and carry a coded message rather like a computer programme and make us what we are, for example giving us a particular hair colour.

We have two copies of all our chromosomes (except the sex chromosomes) and we inherit one copy from our mother and one from our father. In galactosaemia the child inherits a mistake in the area that codes for the missing enzyme from both parents. The parents are perfectly healthy because they have one normal gene which allows them to make enough of the enzyme to keep them healthy. There is no way of knowing that a parent may carry this disorder until they have an affected child. In each and every pregnancy there is a 1:4 chance of having another affected baby.

We can look for the genetic mistake (or mutation) in the DNA and when we do this we find that in quite a high proportion of children there is the same mutation. We are trying to look to see whether the mutation is related in any way to the sorts of problems that children with galactosaemia have, but at the moment there only seems to be a loose association between the mutation and outcome of affected children.

How Common is Galactosaemia?
Galactosaemia is rare. In the UK, about 1 child in 45,000 is born with this condition so between 12 and 18 children are born each year with it.

Making the Diagnosis
Someone with galactosaemia is unable to break down and use galactose. The main dietary source of galactose is lactose which is found in milks. This is why the baby becomes unwell, usually in the first week, having appeared completely normal at birth. Galactose and galactose-1-phosphate levels rise in the baby’s blood and he/she becomes ill.

Signs of liver disease including jaundice, lethargy, poor feeding and weight loss are very common. The severity of the liver disease varies a lot. Babies can also be prone to infection at this stage, although this does not continue to be a problem. Cataracts may also be present. These symptoms are not just seen in galactosaemia and the paediatrician looking after your baby will do a range of tests to make the diagnosis.

The diagnosis is made by measuring the level of the enzyme in your baby’s blood. If he/she has been given a blood transfusion your doctor may need to take blood from both parents to make the diagnosis.

Once the galactose free diet has been started the liver disease will disappear and the baby will start to gain weight normally. Over time the cataracts will also disappear.

What is the Treatment for Galactosaemia?
The most important part of the treatment is to exclude galactose from the diet. The main source of this in the diet is lactose in milk and milk products. This means that people with galactosaemia have a special milk and cannot eat any foods containing milk like butter and yoghurt.

Many packet or tinned foods contain milk in some form so you need to check all types of manufactured food to see if they contain milk before using. ‘Whey’ and ‘casein’ are derived from milk and need to be avoided. Galactose is even found in some medicines (particularly those in tablet form). This sounds very difficult at first but you will be in close touch with a dietitian who will always be able to help if you need to check anything.

Foods are labelled much more clearly now than in the past and the Galactosaemia Support Group can provide a lot of extremely helpful information, including a booklet about the diet and lactose free lists of manufactured foods that are suitable to eat.

You will soon become confident in dealing with the diet and remember help is always available. The diet should be continued throughout life. In some adults however, occasional lapses do not seem to cause problems.

What will happen once the Baby is on the Diet?
The paediatrician will make sure the liver disease and cataracts have disappeared completely and will then make sure that the baby grows normally. There should be no long-term liver or eye problems. He/she will need regular medical and developmental checks which will be organised for you. At first these appointments will be quite often but gradually they will be less frequent.

Other than excluding galactose the baby, child and adult with galactosaemia can be treated as completely normal. If a medicine needs to be given urgently for a serious illness the possibility of the medicine containing lactose is less important than the illness being treated. Immunisations should be given at the normal time.

Long Term
Unfortunately some children develop speech and language and/or learning difficulties, especially in maths and science. We are not entirely sure whether this is because of some damage which may have occurred in the womb (this is no fault of the mother), or whether it is because all of us make a small amount of galactose in our own bodies. This then affects the brain but does not cause the liver disease to recur.

There is no way of preventing this at present. The speech and language difficulties consist mainly of problems with organising speech and the term used for this is oromotor dyspraxia. There may also be a problem with movements which is called motor dyspraxia. This leads to slowness in completing tasks.

There seems to be no clear association between how ill your baby was initially or how quickly the diagnosis was made and the chance of developing these neurological difficulties. We do not understand why one child has more problems than another. Although we cannot undo these difficulties, by picking them up early we can try to minimise the effect they have on your child’s education and social interactions. For this reason assessments will often be carried out if there are any worries.

In addition to these neurological problems, galactosaemia can affect the ovaries. Many girls do not go into puberty at the right time. This is because their ovaries do not produce enough of the hormone oestrogen. All girls are kept under regular review and, if necessary, puberty can be started by giving them some oestrogen (to replace the hormone that their ovaries are not making). This is done slowly and carefully so that puberty happens at the same speed as for girls that enter puberty naturally. Some adult women have regular periods without receiving hormone treatment but most women continue to need oestrogen replacement (usually in the form of the oral contraceptive pill). Some women with galactosaemia have had babies (who are completely normal) but unfortunately, most women with galactosaemia are infertile or have reduced fertility. There may be ways of getting round this in the future but even now women can have babies by IVF using donor eggs. You will be kept up to date with any new information on fertility treatment.

Possibly related to the hormonal problems, but also due to the diet, older patients may develop osteoporosis. As dietary factors are important, boys can be affected by this just like girls although it is likely to be milder. Calcium supplements and regular exercise will minimise the risk. Again, this is something that will be monitored and will depend on the calcium intake.

None of these problems are life threatening and galactosaemic children are otherwise as healthy as any other child provided they continue on their galactose free diet throughout life. In the future we hope that research will lead to better ways of preventing some or all of the long-term problems in galactosaemia.