MPS Multidisciplinary Center

CHOC and Harbor-UCLA Pediatrics together offer the only place in the Western United States for children to receive comprehensive and coordinated treatment for a rare disease called mucopolysaccharidosis (MPS). In a single visit, patients and their families will see a geneticist, neurologist, endocrinologist, orthopaedic surgeon, and cardiologist, all of whom have expertise to collectively manage MPS and its effects on different areas of the body. Because patients with MPS should be continually checked for complications from the disease, we follow families closely to coordinate regular visits and ensure all of their needs are being met.

Comprehensive Treatment, All in One Place

At the CHOC-Harbor UCLA MPS Multidisciplinary Center, we offer:

  • A comprehensive team of specialists who have expertise in treating children with MPS
  • A single care setting for all diagnostic testing and treatment planning, for the convenience of families
  • Close coordination with your child’s referring pediatrician and local subspecialists
  • A holistic approach to treatment: we keep your child’s current and future health in mind and prepare for meaningful survivorship into adulthood
  • The opportunity for families to participate in clinical and scientific research as we work to understand MPS and discover new and better treatments
  • Connection with support from a nationwide MPS patient advocacy group, the National MPS Society.

On the Leading Edge of Research

centrifuge in the metabolics research lab

The CHOC MPS Multidisciplinary Center team is actively involved in research to further our understanding of MPS and discover the latest treatments and protocols for this disease. Our patients may be invited to participate in clinical trials and studies to try alternate methods of care. Our current research includes:

Clinical Trials

  • A Randomized, Placebo-Controlled, Blind-Start, Single-Crossover Phase 3 Study to Assess the Efficacy and Safety of UX003 rhGUS Enzyme Replacement Therapy in Patients with MPS 7 (Ultragenyx Pharmaceutical)
  • A Phase 1 Safety and Dose-Finding Study of a Human Insulin Receptor Monoclonal Antibody-Human alpha-L-iduronidase (HIRMAb-IDUA) Fusion Protein, AGT-181 in Adult Patients with Mucopolysaccharidosis I (MPS I; Armagen)
  • A Phase 1 Safety and Dose-Finding Study of a Human Insulin Receptor Monoclonal Antibody-Human Iduronate 2-Sulfatase (IDS) Fusion Protein, AGT-182 in Adult with Mucopolysaccharidosis II (MPS II, Hunter Syndrome; Armagen)
  • A Pilot Study of the Effect of Adalimumab on Physical Function and Musculoskeletal Disease in Mucopolysaccharidosis Types I, II and VI (Investigator Initiated).

Clinical/Translational Research

  • Assessment of cardiovascular disease natural history of the Mucopolysaccharidosis Type I Mouse model
  • Carotid Structure and Function in MPS Types I, II, III and VI
  • Manifestations of Cardiovascular Disease in Morquio A Syndrome
  • Intraarticular Gene Therapy for Canine Mucopolysaccharidosis Type I Joint Disease
  • Longitudinal Study of Bone and Endocrine Disease in Children with MPS I, II and VI: A Multicenter Study of the Lysosomal Disease Network
  • Longitudinal studies of brain structure and function in MPS disorders.

Registry Studies

  • MPS I Registry
  • Hunter Outcome Registry
  • Morquio A Registry Study.

Frequently Asked Questions about Mucopolysaccharidosis (MPS)

The mucopolysaccharidoses (MPSs) are a group of related lysosomal storage diseases. Lysosomes are compartments in cells that break down molecules and remove waste products from cells. Normally, different enzymes in the lysosomes break down complex sugars called glycosaminoglycans, also known as mucopolysaccharides. In MPS, glycosaminoglycans are not broken down because of a deficiency in one of those lysosomal enzymes. As a result, the glycosaminoglycans accumulate in the cells and cause tissue damage.

Different types of MPS are classified by the enzymes that are absent or deficient. To date, seven types of MPS have been reported: MPS I, II, III, IV, VI, VII and IX.

All types of MPS are inherited and share very similar physical symptoms. The physical symptoms may include thickening of lips and skin, enlarged liver and spleen, hernias, recurrent ear infections requiring ear tube placement, joint pain and stiffness, and short stature. Neurological symptoms are present in some types of MPS and may vary in severity.

It is estimated that in the United States, one in 25,000 births are affected by some form of MPS. MPS III, also called Sanfilippo syndrome, is one of the more common types, while MPS VII is very rare. Lifespan of a patient with MPS varies depending on the severity and type of disease but it is possible for a person with a mild form of MPS to live into adulthood.

There is currently no known cure for MPS. Therapies that aim to replace the deficient enzymes may help improve upper airway problems, reduce liver and spleen enlargement and improve overall well-being. Other aspects of treatment aim to relieve and manage symptoms in order to improve and prolong life. Sometimes, physical therapy or orthopaedic surgery is required for correcting skeletal abnormalities.
Each type of MPS has different symptoms and has varying degrees of severity. All types have a period of normal growth that is followed by a decline in physical and mental functioning.

Common physical symptoms include:
  • Thickened lips and skin
  • An enlarged tongue
  • Enlarged organs, specifically the liver and spleen
  • Recurrent ear or sinus infections
  • Inguinal and/or umbilical hernias
  • Abnormal bone size and shape
  • Joint pain and stiffness
  • Corneal clouding
  • Short stature.
Neurological symptoms may occur in some types of MPS. They may include:
  • Decreased intellectual capacity
  • Hyperactivity
  • Insomnia
  • Delirium
  • Aggressive behavior
  • Loss of previously acquired developmental milestones.
Effects on breathing function may include:
  • Sleep apnea
  • Obstructive airway disease
  • Chronic respiratory infections
  • Enlarged tonsils and adenoids
  • Noisy and difficult breathing.
Heart abnormalities may be more common in some types of MPS than others. These abnormalities may include:
  • Valve defects
  • Thickening and stiffening of the heart wall
  • Narrowing of blood vessels.
At our MPS Multidisciplinary Center, we have a team of pediatric specialists from multiple fields to treat any of the symptoms that may occur because of MPS.
MPS may be suspected after a thorough physical examination if your physician notices the different symptoms and findings that are characteristic of MPS. An elevated level of glycosaminoglycans may also be detected in the urine, suggesting the possibility of mucopolysaccharidosis.

If MPS is suspected, measurement of lysosomal enzymes and DNA testing are then performed to identify the specific type of MPS.
Patients should be continually followed by their physician to be assessed for declining physical and mental functioning. Depending on the type of mucopolysaccharidosis (MPS), patients may need to be evaluated more often than others due to differences in disease progression and severity.

Neurologic: Certain types of MPS result in cognitive disabilities. Narrowing or compression of spinal nerves may result in weakness and changes in sensation of the arms and legs.

Cardiovascular: Common heart abnormalities may include valve defects, thickening and stiffening of the heart wall, and narrowing of blood vessels. Complications of heart abnormalities are cardiovascular collapse and death if not corrected. Surgery and prescription medications may be useful in preventing complications.

Respiratory: Effects on breathing function include sleep apnea, obstructive airway disease, chronic respiratory infection, enlarged tonsils and adenoids, and noisy and difficult breathing. Chronic respiratory infections can lead to pneumonia, which can be life-threatening if untreated. Enlarged adenoids and tonsils may contribute to difficulty breathing and sleep apnea.

Skeletal: Abnormal bone and cartilage formation result in joint pain, stiffness, and decreased mobility and quality of life. Bone abnormalities may compress nerves, leading to inhibition of normal neurological function.

Endocrinology: Short stature, growth hormone and other hormonal deficiencies, and reduced bone mineral density are very common in patients with MPS.

At our MPS Multidisciplinary Center, we have a team of pediatric specialists from multiple fields to treat any of the symptoms that may occur because of MPS.
Currently, there is no known cure for any form of mucopolysaccharidosis (MPS), but there are treatments available to manage symptoms, prevent complications and improve quality of life. Physical therapy may be helpful in the prevention and treatment of joint pain and stiffness that is common in all types of MPS.

Hematopoietic cell transplantation: The use of hematopoietic cell transplantation may be beneficial when performed at an early age in MPS I, providing cells that produce the missing enzymes. The use of early hematopoietic cell transplantation may help to prevent neurodegeneration and improve other symptoms, but does not reverse damage that has already happened. At CHOC, we offer the only pediatric blood and marrow transplant program in Orange County with experience in hematopoietic cell transplantation for MPS I. Learn more about the Blood and Marrow Transplantation (BMT) Program.

Enzyme replacement: Recombinant enzyme products are available for the treatment of specific types of MPS. Depending on the enzyme that is deficient or missing, the appropriate enzyme replacement may help in reducing some of the symptoms associated with whatever disease is being treated. Research has shown that liver and spleen enlargement, as well as exercise endurance, may improve with enzyme replacement therapy. CHOC Children’s can provide provide treatment for all forms of MPS for which enzyme replacement is approved by the U.S. Food and Drug Administration.

Surgery: Various types of surgery have been performed depending on the symptom being treated. For patients with sleep apnea and obstructive airway disease, the removal of tonsils and adenoids may be beneficial in improving breathing. Surgery has also been used to relieve compression on nerves and the spinal cord, repair hernias, fix heart abnormalities, and to place shunts to allow for drainage of cerebrospinal fluid. Our MPS Multidisciplinary Center offers pediatric surgeons in all areas to address any of these needs. Learn more about having surgery at CHOC.

Genetic testing and counseling: Individuals with a family history of MPS or who have MPS may meet with genetic counselors to discuss the risks of having additional affected children, and counseling for reproductive options.

Contact Us

An entire team of specialists from CHOC and Harbor-UCLA Pediatrics partner in one location to provide coordinated care for patients with MPS and other conditions that can result from the disease. We offer a unique expertise in MPS not seen at most hospitals.

To schedule an appointment at the MPS Multidisciplinary Center, please call 888-770-2462 and select “Specialty Care Clinics.” Please call 714-509-8852 with any additional questions about our program.

CHOC Clinic
1201 W. La Veta Ave.
Orange, CA 92868

The MPS Team

Dr. Raymond Wang, Metabolic/Lysosomal Disorders
Dr. Patti Dickson, Genetics/Lysosomal Disorders
Dr. Afshin Aminian, Orthopaedics
Dr. Agnes Chen, Neurology
Dr. Grace Mucci, Neuropsychology
Dr. Lynda Polgreen, Endocrinology
Dr. Michael Recto, Cardiology