A team led by Shunji Tomatsu, MD, PhD, principal research scientist with Nemours Biomedical Research, has been conducting early stage investigation on a gene therapy for Morquio A syndrome. Preliminary data in mice models suggest that this approach could slow or prevent the progression of disease in bone and cartilage.
Morquio syndrome Type A is a rare lysosomal storage disease characterized by short stature, a large head, severe scoliosis, cervical spinal cord compression, tracheal obstruction, distinctive facial features and in some cases, heart, liver and vision problems.
Morquio A syndrome is estimated to occur in one in 250,000 births worldwide. About 500 people in the United States are known to have Morquio A syndrome. The disease may not be apparent at birth; symptoms may become noticeable between ages 1 and 3 and get worse as the child grows.
Morquio A syndrome is part of a group of diseases called mucopolysaccharidoses (MPS). In children with Morquio A syndrome, the body cannot break down sugar chains called glycosaminoglycans (GAGs) that are present in bone, cartilage, eye corneas, skin and connective tissue (tendons, ligaments, etc.) As a result, GAGs collect in cells, blood, and connective tissue and cause damage over time. In Morquio A syndrome, the enzyme called galactosamine-6-sulfatase is missing. The damage caused by the lack of the enzyme affects a child’s appearance, tissues, bones, organ function and physical abilities. Bone problems can lead to major health problems. For example, the small bones at the top of the neck may slip and injure the spinal cord, causing paralysis. Surgery to correct problems such as these should be done if possible.
In addition to surgery, the gold standard of treatment for Morquio A syndrome has been Enzyme Replacement Therapy (ERT). However, ERT is expensive, involves a weekly five-hour intravenous infusion, and has limited impact on patients’ severe bone pathology.
Dr. Tomatsu’s research showed that enzyme activity was elevated in treated mice, resulting in complete clearance of GAG storage in certain cells and reduced storage in others. The high enzyme levels combined with longer circulation time could have led to increased penetration into bone and cartilage thereby improving storage in those regions. The results of these data have been presented at the Fourth Morquio Conference (July 29; Nemours) and at the 15th Annual International Symposium on MPS and Related Diseases (August 2-4; San Diego, CA).
Nemours/Alfred I. duPont Hospital for Children is renowned for its clinical and research expertise in Morquio syndrome and has been caring for Morquio patients for 30 years. The hospital actively treats more than 70 patients with Morquio, (including Carly, inset) many of whom attended the recent conference hosted by Nemours.
Last updated on 9/25/19.