What is Morquio syndrome?

Sam Brown, who is one of just 88 people in the UK with the ultra-rare condition Morquio Syndrome. PIC: PA
Sam Brown, who is one of just 88 people in the UK with the ultra-rare condition Morquio Syndrome. PIC: PA
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Morquio syndrome, also known as MPS IVA, is an inherited condition that affects bone development and restricts growth.

It is a recessively inherited disease meaning that if both parents carry the particular gene, their child has a 25% chance of developing the condition.

Morquio is an incurable condition caused by a lack or low supply of the enzyme N-acetylgalactosmine-6 sulfatase (known as GALNS), which is supposed to break down the cellular molecule glycosaminoglycan (known as GAG).

Without GALNS, people with Morquio suffer a build up of GAG in their tissues, bones and major organ systems.

This can lead to an assortment of symptoms, including heart disease, skeletal abnormalities, loss of sight or hearing, breathing difficulties and lowered life expectancy.

It can also limit endurance, making even the most everyday tasks difficult to complete without extreme exhaustion.

Morquio is a progressive condition, meaning that its symptoms will get worse over time if untreated.

Its symptoms are usually spotted in people as early as two or three years old.

The average life expectancy for someone with Morquio is 25 years.

Early diagnosis is vital to begin therapy as soon as possible and Morquio can be tested for with both a urine and genetic test.

Testing is useful for parents with a child who has Morquio, to assess the likelihood of the condition affecting any further children they have, and people whose siblings have the condition to test if they may be a carrier for the faulty gene.

Morquio is what is known as an ‘orphan disease’ in the USA, a term which describes any disease affecting less than 200,000 people.

In England, Morquio is ultra-rare, affecting only 88 people including six-year-old schoolboy Sam Brown from Otley.

The rarity of the condition inevitably leads to high prices for the medicinal treatment used to manage it, the drug Vimizim.

Vimizim was developed by BioMarin Pharmaceutical Inc. in California, US. It replaces the missing GALNS enzyme, improving energy, stamina and the ability to walk.

It also preserves vision as it stops corneal clouding, lessens chest infections and breathing difficulties, improves sleep and makes pain levels manageable.

Vimizim is proven to work with no severe side effects but the rarity of the condition means that it is priced at £395,000 per person per year in the UK.

BioMarin made the drug available to people with Morquio for free on a trial basis, but that trial expired in May this year.

Withdrawal from the drug leads to an immediate backslide, with the symptoms of the condition continuing to progress and worsen.


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