What causes this disease?

There is a continuous process in the body of replacing used materials and breaking them down for disposal. Children with Sanfilippo disease are missing an enzyme which is essential in cutting up the used mucopolysaccharides. The incompletely broken down mucopolysaccharides remain stored in cells in the body causing progressive damage. Babies and small children may show little sign of the disease but, as more and more cells become damaged, symptoms start to appear.

How common is Sanfilippo disease?

The MPS Society which co-ordinates the Registry for Mucopolysaccharide and Related Diseases has shown that this is a rare condition affecting one in 85,000 live births. Over a ten-year period between 1980 and 1990, 88 babies with Sanfilippo disease were born in the United Kingdom.

Is there a cure?

At present there is no cure for any of the mucopolysaccharide diseases. Various experimental methods have been used to try to replace the missing enzyme, but none has so far been of any significant long-term benefit. Bone marrow transplant has been tried on Sanfilippo patients, but with disappointing results and is now never recommended for this condition.

How does the disease progress?

The disease tends to progress through three main stages.

The first during the child's pre-school years may be a very frustrating one for the parents. They begin to worry as their child starts to lag behind their friends' children in development and they may feel they are being blamed for the child's overactive and difficult behaviour.

The diagnosis is often made very late as some children do not look in any way different and their symptoms such as diarrhoea, frequent respiratory and ear infections and boisterous behaviour are among the most common seen in all children. The doctor has to be perceptive enough to recognise that something serious is wrong and to ask for urine and blood tests to help reach a diagnosis. It is not unusual for families to have had more than one affected child before the diagnosis is established.

The second phase of the disease is characterised by extremely active, restless and often very difficult behaviour. Some children sleep very little at night. Many will be into everything and one parent writes 'taps are a great favourite, we're always having floods'. Many like to chew; hands clothes or anything they can get hold of 'even the contents of ashtrays are not missed out.'

Sadly, language and understanding will gradually be lost and parents may find it hard not being able to have a conversation with their child. Many will find other ways of communicating, perhaps using sign language such as the Makaton system. 'She loves me to talk to her and she smiles with her eyes, almost talks with them and her whole face lights up with love.' Some children never become toilet trained and those who do will eventually lose this ability.

In the third phase of the disease Sanfilippo children begin to slow down. They become more unsteady on their feet, tending to fall frequently as they walk or run. Eventually they lose the ability to walk. Life may be more peaceful in some ways, but parents will need help with the physically tiring task of caring for an immobile child or teenager and with all the changes necessary to provide for their care.