From the Guidelines
Morquio syndrome is a rare inherited metabolic disorder that requires early diagnosis and multidisciplinary care to improve quality of life and manage complications, with treatment focusing on symptom management through enzyme replacement therapy, physical therapy, pain management, and surgical interventions. The condition is characterized by the body's inability to break down specific complex carbohydrates, leading to the accumulation of glycosaminoglycans in cells, tissues, and organs 1. Patients typically appear normal at birth but develop distinctive physical features, including short stature, skeletal abnormalities, spinal cord compression, heart valve problems, cloudy corneas, hearing loss, and dental abnormalities.
Key Characteristics and Treatment
- The condition belongs to a group of diseases called mucopolysaccharidoses (specifically MPS IV) and exists in two forms: Type A (more severe, caused by GALNS gene mutations) and Type B (milder, caused by GLB1 gene mutations) 1.
- While there is no cure, treatment focuses on symptom management through enzyme replacement therapy (elosulfase alfa for Type A), physical therapy, pain management, and surgical interventions for skeletal issues.
- Genetic counseling is recommended for affected families as the condition is inherited in an autosomal recessive pattern, meaning both parents must carry the gene mutation for a child to develop the syndrome.
- Early diagnosis and multidisciplinary care are essential for improving quality of life and managing complications, with a focus on reducing morbidity, mortality, and improving quality of life 1.
Importance of Recent Evidence
The most recent and highest quality study on the treatment of mucopolysaccharidosis type II (Hunter syndrome) provides valuable insights into the management of similar conditions, including Morquio syndrome 1. Although the study focuses on Hunter syndrome, its findings on the importance of early diagnosis, enzyme replacement therapy, and multidisciplinary care can be applied to Morquio syndrome, highlighting the need for a comprehensive approach to managing these complex conditions.
From the Research
Overview of Morquio Syndrome
- Morquio syndrome, also known as mucopolysaccharidosis IVA, is a lysosomal storage disorder characterized by skeletal and joint abnormalities, as well as non-skeletal manifestations such as respiratory disease, spinal cord compression, cardiac disease, impaired vision, hearing loss, and dental problems 2.
- The clinical presentation, onset, severity, and progression rate of Morquio A syndrome vary widely between patients, making management challenging and requiring a multidisciplinary approach 2.
Management and Treatment
- International guidelines for the evaluation, treatment, and symptom-based management of Morquio A syndrome have been developed by an international panel of specialists 2.
- Elosulfase alfa is an enzyme replacement therapy approved for the treatment of Morquio A syndrome, which has been shown to be safe and well-tolerated in patients 3, 4.
- The immunogenicity profile of elosulfase alfa has been assessed, and while all patients developed antibodies to the drug, this did not correlate with reduced treatment effect or worsened safety outcomes 3, 4.
Clinical Outcomes and Case Reports
- A case report of a 73-year-old woman with Morquio syndrome undergoing transcatheter aortic valve implantation highlights the challenges of managing aortic valve disease in patients with Morquio syndrome, but suggests that the procedure can be safely performed using a surgical femoral cut-down approach 5.
- Another case report describes the efficacy and safety of elosulfase alfa in a severely affected, non-ambulatory Japanese patient with Morquio A syndrome, showing significant respiratory improvement and other clinical benefits 6.
- A study of patients with Morquio A syndrome participating in two sequential open-label studies of elosulfase alfa enzyme replacement therapy showed no trends toward decreasing endurance, respiratory function, or ability to perform activities of daily living over a 5-year period 3.