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What is MPS IVA?

Mucopolysarcharidosis type IVA (MPS IVA), also known as morquio syndrome type A, is a rare, inherited disorder. MPS IVB is one of 50 diseases classified as lysosomal storage disorders (LSD), in which a genetic variation disrupts the normal activity of lysosomes in human cells.

What are lysosomes and what do they do?

Lysosomes contain specific proteins (enzymes) responsible for breaking down and recycling molecules such as fats and sugars. Individuals with a lysosomal storage disorder lack one of these necessary enzymes or do not have one of these enzymes in sufficient quantities to break down molecules for proper cell function.

Symptoms & Causes

What are the symptoms of MPS IVA?

Manifestations of MPS IVA fall on a broad spectrum, meaning children may or may not have symptoms. Children with MPS IVA generally do not experience or display symptoms at the time of their birth. Over time, they may develop skeletal abnormalities including:

Over time, children may develop additional symptoms, including:

  • Sleep apnea
  • Hearing loss or impairment
  • Visual impairment/corneal clouding
  • Enlargement of the liver and spleen
  • Dental abnormalities
  • Thickening/impairment of the heart valves
  • Compression of the spinal cord

What causes MPS IVA in children?

MPS IVA is caused due to a deficiency in an enzyme known as N-acetylgalactosamine-6-sulfatase. This condition is genetic and is inherited in an autosomal recessive pattern, which means that an affected child has received one defective copy of the gene responsible for N-acetylgalactosamine-6-sulfatase production from each parent.

Diagnosis & Treatments

How do we treat MPS IVA?

Current approaches to MPS IVA are tailored to specific patients and may include enzyme replacement therapy (ERT) and targeted symptom management. Treatment plans require interdisciplinary collaboration and depend greatly on a patient’s specific disease presentation.

How we care for MPS IVA

At the Boston Children’s Lysosomal Storage Disorders (BoLD) Program, our team of providers is committed to the care of complex patients. As part of Boston Children’s Hospital, we are prepared to meet the challenge of providing multifaceted care by partnering with you and your child to deliver direct care in our BoLD clinic. We work with the broad array of world-class specialists at Boston Children’s to optimize the care we provide your child with MPS IVA.