Rare Classroom: Maroteaux-Lamy Syndrome

Welcome to the Rare Classroom, a new series from Patient Worthy. Rare Classroom is designed for the curious reader who wants to get informed on some of the rarest, most mysterious diseases and conditions. There are thousands of rare diseases out there, but only a very small number of them have viable treatments and regularly make the news. This series is an opportunity to learn the basics about some of the diseases that almost no one hears much about or that we otherwise haven’t been able to report on very often.

Eyes front and ears open. Class is now in session.

The disease that we will be learning about today is:

Maroteaux-Lamy Syndrome

Also called mucopolysaccharidosis VI (MPS VI)​.

What is Maroteaux-Lamy Syndrome?

  • A lysosomal storage disorder
  • Cell compartments (lysosomes) fill up with a sugar molecule called glycosaminoglycan (GAG)
  • MPS VI is caused by the buildup of GAG in lysosomes in organs and tissues throughout the body
  • It affects the lungs, heart, bones, eyes and other organs
  • The symptoms can be mild or life-threatening
  • MPS VI is a rare disease; it happens in only about 1 out of every 340,000 live births

How Do You Get It?

  • MPS VI is an inherited disease
  • MPS VI is caused by an inherited genetic change that causes a person to be deficient in the enzyme arylsulfatase B(ASB).
  • Genes carry the instructions for traits like eye color and hair color as well as a multitude of instructions that our body needs to function properly, including instructions to make ASB and all other enzymes
  • Genes are inherited in pairs-one copy from each parent
  • People who have one working ASB gene and one nonworking gene are called carriers; they make enough ASB to remain healthy and do not have MPS VI.
  • Individuals who have MPS VI, have inherited 2 nonworking copies of the ASB gene-one from each parent
  • An estimated 1,100 people worldwide are living with MPS VI
  • People with MPS VI generally do not display any features of the condition at birth.
  • They often begin to show signs and symptoms during early childhood.
  • MPS VI affects males and females equally

What Are The Symptoms?

  • Ear, Nose, Throat
    • Narrowed nostrils due to flattened nasal bridge
    • Buildup in the soft tissues (enlarged tonsils, tongue)
    • Excess production of thick mucus
    • Constant stuffy nose and infection
    • Ear infections
    • Hearing loss
    • Narrowed airway
  • Heart and Circulatory System
    • GAG builds up in the heart
    • Tend to worsen with age
    • High blood pressure
    • Artery clots
    • Heart valve disease
  • Bones and Joints
    • Joint function, bone and skeletal development are impacted
    • Slowed growth
    • Short stature
      • Tends to be more severe in rapidly progressing disease
    • Pronounced forehead
    • Large head
    • Abnormal rib cage
    • Scoliosis
    • Gait changes
    • Joint problems
  • Eyes
    • 40 percent have vision impairment
    • Clouding of the cornea
    • Glaucoma
    • Eye pressure
    • Optic nerve changes
  • Lungs and Breathing
    • Lung function is often impacted
    • Can be a concern during surgery or anesthesia
    • May be fatal
    • Narrowed airways
    • Infections
    • Abnormal chest shape
  • Brian and Nerves
    • Increased brain pressure
    • Carpal tunnel syndrome
    • Neural compression

How is it Treated?

  • Tailored to the individual case
  • Often symptomatic in nature
  • Surgery
    • Heart valve replacement
    • Remove tonsils, adenoids
    • Hernias, carpal tunnel, skeletal problems
  • Physical therapy
  • Exercise
  • Anti-inflammatory medication
  • Enzyme replacement therapy
    • Naglazyme
    • Approved by the FDA in May 2005
      • Cleared in the US, EU, and several other countries
    • Replaces the missing enzyme with a substitute enzyme
    • Administered by IV infusion
    • Improved endurance and mobility

Where Can I Learn More???

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