Lysosomal storage diseases

Morquio A syndrome (MPS IVA)

An inherited storage disease. The body cannot break down some large sugar molecules. The skeleton is affected most; intelligence is not affected.

Not part of the panel of Türkiye's National Newborn Screening Programme (heel-prick test). Source

Prepare an emergency card

This page is translated from the Turkish original.

This disease is followed through the “Lysosomal storage diseases” group.

Understanding the disease

This section has not yet been reviewed by a physician. It summarises patient information from sources such as MedlinePlus, Orphanet and the NHS in plain language. The disease can differ from person to person; talk to your doctor about diagnosis and treatment.

What happens in this disease?

A change in the GALNS gene leaves an enzyme missing. This enzyme breaks down large sugar molecules called GAGs. GAGs build up in the cells, mostly in the bones. Symptoms usually begin in early childhood and increase over time.

Which symptoms can occur?

How fast the disease progresses varies from person to person.

Short stature, knock knees
Changes in the shape of the chest, spine, hips and wrists
Very flexible, loose joints
Looseness of the neck bones and a risk of pressure on the spinal cord
Clouding of the clear front layer of the eye
Frequent ear infections and hearing loss
Pauses in breathing during sleep, frequent airway infections
Heart valve problems

How is it diagnosed?

An examination, skeletal X-rays and measuring GAGs in the urine suggest the disease. The GALNS enzyme is found to be low in the blood or in skin cells. A genetic test examines the GALNS gene.

Treatment and care

There is an approved enzyme replacement therapy for this disease. Surgery that stabilizes the neck bones protects the spinal cord. Tonsil surgery, hearing aids, a corneal transplant or heart valve surgery may be needed. Physiotherapy and support at school make daily life easier. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

The disease is passed on through recessive inheritance. The mother and father are usually healthy carriers. For a couple who are both carriers, the chance of having an affected child is 1 in 4 in each pregnancy. Diseases of this kind may be more common in marriages between relatives. Genetic counselling guides the family.

Source: MedlinePlus Genetics: Mucopolysaccharidosis type IV · NORD: Mucopolysaccharidosis IV

Key facts

How common is it?: Prevalence: 1-5 per 10 000 (Europe)
How is it inherited?: Autosomal recessive
When does it usually start?: Childhood
Gene(s) involved: GALNS
Reliable sources: MedlinePlus (for families) · Orphanet

These facts are taken from Orphanet and MedlinePlus records (last checked: October 7, 2026). Frequency values are approximate ranges.

You are not alone: patient associations in Türkiye

Non-profit patient and family organizations in Türkiye working on this disease or disease group. Links are for information; Doktorclub is not affiliated with these organizations and does not endorse them.

Mukopolisakkaridoz ve Benzeri Lizozomal Depo Hastalıkları Derneği · Specific to this disease · İstanbul

For all rare diseases: Nadir Hastalıklar Federasyonu

Links checked on October 8, 2026.

Guides related to this disease

Rare disease at school · Telling the school, medicines and emergency plan, inclusion and BEP, support education room, absences, LGS/YKS arrangements, peer bullying.

Support and help

In an emergency in Türkiye, call 112.
For psychological and social support, the ALO 183 Social Support Line (24/7, free from within Türkiye): alo183.aile.gov.tr
For carers: Looking after yourself as a caregiver
Preparing for a doctor visit · Collect your questions and symptom notes on one page, then print it and take it with you.

Doktorclub does not diagnose, recommend treatments or refer you to hospitals or doctors. These pages are meant to help you talk with your doctor.

News about Morquio A

TürkiyeResearch and clinical trialsJune 24, 2026

MPS IVA and VI patients on enzyme therapy in Istanbul: leg findings improved slightly over two years

In Istanbul, 14 MPS patients receiving enzyme therapy were followed for two years.

Peer-reviewed publicationMorquio A

GlobalResearch and clinical trialsJanuary 28, 2026

Stem cell transplantation in Morquio A syndrome: three-year survival of 90.5% in 41 patients at 9 centers

An international study pooling the results of stem cell transplantation in Morquio A syndrome has been published.

Peer-reviewed publicationMorquio A

Clinical trials (ClinicalTrials.gov)

A clinical trial is a regulated study that tests whether a new treatment is safe and whether it works, in patients who volunteer. Most trials look for a certain age, genetic change and health condition. Taking part is voluntary.

This list is not a treatment recommendation. Treatments tested in phase 1–3 trials are investigational (experimental): their efficacy and safety have not yet been proven and they are not approved treatments. Taking part depends on each trial’s criteria and a physician’s assessment; the first step is to talk to the doctor who manages your care.

Questions you can ask your doctor

Could this trial be suitable for us?
If we take part, how would current treatment and check-ups be affected?
Where does the trial take place, and how are travel and accommodation handled?
What happens if we want to leave the trial?

ClinicalTrials.gov lists 2 active interventional studies for this disease. 1 is recruiting now; none has a site in Türkiye. Last checked: October 7, 2026.

Selected records (studies with a site in Türkiye first):

PEARL (PrEnAtal Enzyme Replacement Therapy for Lysosomal Storage Disorders)
Early stage: safety and dose are being tested · Phase 1 · investigational (experimental)RecruitingNCT04532047
Safety and Efficacy of Voxzogo for Growth Deficits in MPS IVA and VI
Middle stage: the effect is being tested in a small group · Phase 1 / Phase 2 · investigational (experimental)Active, not recruitingNCT05845749

See all studies on ClinicalTrials.gov · Joining clinical trials

Lysosomal storage diseases: other news

InternationalResearch and clinical trialsSeptember 25, 2026

In Hunter syndrome, siblings who started enzyme therapy in infancy did better

Records of 19 sibling pairs with Hunter syndrome were compared.

Peer-reviewed publicationMPS II

USANew treatments and approvalsSeptember 17, 2026

Rebisufligene etisparvovec receives FDA approval as first treatment for Sanfilippo type A

The FDA has approved rebisufligene etisparvovec for children with Sanfilippo syndrome type A (MPS IIIA).

Official drug approvalMPS IIIA

ChinaResearch and clinical trialsJuly 23, 2026

Gene therapy tested in 6 children with infantile-onset Pompe disease

In China, 6 children with infantile-onset Pompe disease were given a single dose of gene therapy.

Peer-reviewed publicationPompe

Medical codes (for talking with your doctor and finding sources)

These codes identify the disease in international classifications and databases. They can help when you talk with your doctor or look for reliable sources.

Orphanet code: ORPHA:309297

No separate ICD-11 code; WHO classifies this disease under: 5C56.32

Codes checked against WHO ICD-11 and Orphanet on October 7, 2026.

This page provides general information and does not replace diagnosis or treatment. Talk to your doctor about symptoms, diagnosis and treatment.