MPS VI – Maroteaux-Lamy Disease

Martina Lynch

Maroteaux-Lamy disease, also known as MPS VI, is one of the rarer mucopolysaccharide diseases. It takes its name from two French doctors, Dr Maroteaux and Dr Lamy, who first described the condition in 1963.

What causes this disease?

There is a continuous process in the body of replacing used materials and breaking them down for disposal. Children with Maroteaux-Lamy disease are missing an enzyme which is essential in cutting up the mucopolysaccharide called dermatan sulphate. The incompletely broken down mucopolysaccharides cannot be used in the proper development of bones and cartilage and remain stored in cells in the body causing progressive damage. Babies may show little sign of the disease but, as more and more cells become damaged, symptoms start to appear.

How is the disease inherited ?

We all have genes inherited from our parents which control whether we are tall, short, fair etc. Some genes we inherit are ‘recessive’, that is to say we carry the gene but it does not have any effect on our development. Maroteaux-Lamy disease is caused by a recessive gene. If an adult carrying the abnormal gene has a partner who is another carrier there will be a one in four chance with every pregnancy that the child will inherit the defective gene from each parent and will suffer from the disease.

There is a two in three chance that unaffected brothers and sisters of children with Maroteaux-Lamy disease will be carriers. They can be reassured however that, as the disease is so rare, the chance of having a partner who is another carrier is very slight as long as their partner is not a cousin or other blood relative.