Summary about Disease
Maroteaux-Lamy syndrome, also known as mucopolysaccharidosis type VI (MPS VI), is a rare, inherited metabolic disorder caused by a deficiency of the enzyme arylsulfatase B (ARSB). This enzyme is needed to break down glycosaminoglycans (GAGs), also known as mucopolysaccharides. The buildup of GAGs in various tissues and organs throughout the body leads to a range of symptoms affecting skeletal, cardiac, respiratory, and neurological systems. The severity of symptoms can vary greatly among affected individuals, ranging from mild to severe forms of the disease.
Symptoms
Symptoms of Maroteaux-Lamy syndrome are progressive and can vary widely. Common symptoms include:
Skeletal Abnormalities: Dysostosis multiplex (characteristic bone abnormalities), short stature, joint stiffness, hip dysplasia, scoliosis, kyphosis, claw hand.
Cardiac Issues: Heart valve thickening, cardiomyopathy.
Respiratory Problems: Obstructive airway disease, sleep apnea.
Ophthalmological Problems: Corneal clouding, glaucoma, optic nerve swelling.
Neurological Issues: Spinal cord compression (leading to neurological deficits), hydrocephalus.
Other: Coarse facial features, enlarged tongue, enlarged liver and spleen (hepatosplenomegaly), hernias, hearing loss.
Hydrocephalus
Carpal Tunnel Syndrome
Causes
Maroteaux-Lamy syndrome is caused by mutations in the ARSB gene. This gene provides instructions for making the enzyme arylsulfatase B. Mutations in the *ARSB* gene result in a deficiency or absence of this enzyme. Because arylsulfatase B is needed to break down specific GAGs (dermatan sulfate), these substances accumulate in cells throughout the body. This accumulation leads to cell damage and the various symptoms of MPS VI. The condition is inherited in an autosomal recessive pattern, meaning that both parents must carry a copy of the mutated gene for a child to be affected.
Medicine Used
Enzyme Replacement Therapy (ERT): The primary treatment is enzyme replacement therapy with galsulfase (Naglazyme). This medication provides a synthetic version of the arylsulfatase B enzyme, helping to break down GAGs and reduce their accumulation in tissues. ERT can improve some symptoms and slow disease progression.
Hematopoietic Stem Cell Transplantation (HSCT): In some cases, HSCT (bone marrow transplant) may be considered, particularly in younger patients. HSCT aims to provide a new source of arylsulfatase B. However, HSCT carries significant risks and is not suitable for all patients.
Symptomatic Management: Other treatments focus on managing specific symptoms, such as pain medications, physical therapy, surgery for skeletal abnormalities or carpal tunnel syndrome, cardiac medications, and respiratory support.
Is Communicable
No, Maroteaux-Lamy syndrome (MPS VI) is not communicable. It is a genetic disorder caused by a gene mutation and cannot be spread from person to person through any infectious means.
Precautions
While Maroteaux-Lamy syndrome isn't communicable, precautions focus on managing the existing condition and preventing complications:
Regular Monitoring: Regular check-ups with a multidisciplinary team of specialists are crucial to monitor disease progression and manage symptoms.
Vaccinations: Following standard vaccination schedules is important, but discuss any specific concerns with the patient's doctor.
Anesthesia Considerations: Individuals with MPS VI often have airway and cardiac issues, requiring careful planning and monitoring during anesthesia for any surgical procedures.
Physical Therapy: Maintain physical activity as tolerated to maintain mobility and prevent joint contractures.
Cardiac Monitoring: Regular cardiac evaluations are necessary to manage heart valve problems or cardiomyopathy.
Avoidance of Trauma: Protect against injuries that could exacerbate skeletal problems.
How long does an outbreak last?
Maroteaux-Lamy syndrome is not an infectious disease and does not involve outbreaks. It is a chronic, progressive condition that lasts throughout the individual's lifetime. There is no outbreak period.
How is it diagnosed?
Diagnosis of Maroteaux-Lamy syndrome typically involves:
Clinical Evaluation: Assessment of symptoms and physical examination to identify characteristic features.
Urine Testing: Measuring levels of GAGs (dermatan sulfate) in the urine. Elevated levels suggest an MPS disorder.
Enzyme Assay: Measuring the activity of arylsulfatase B enzyme in blood or skin cells (fibroblasts). Reduced or absent enzyme activity confirms the diagnosis.
Genetic Testing: DNA analysis to identify mutations in the ARSB gene. This can confirm the diagnosis and help with genetic counseling.
Imaging Studies: X-rays, MRI, and echocardiograms may be used to assess skeletal, cardiac, and neurological involvement.
Timeline of Symptoms
The timeline of symptom onset and progression varies significantly.
Early Childhood (Infancy to Early Childhood): Some symptoms, such as coarse facial features, hernias, and frequent respiratory infections, may be apparent in infancy or early childhood.
Childhood: Skeletal abnormalities, joint stiffness, and corneal clouding often become more evident during childhood. Growth slows, and short stature becomes noticeable.
Later Childhood/Adolescence: Spinal cord compression and other neurological complications may develop. Cardiac and respiratory problems may worsen. The rate of progression varies depending on the severity of the disease.
Adulthood: Symptoms continue to progress throughout adulthood, impacting quality of life. The lifespan of individuals with MPS VI varies depending on the severity of the disease and the availability of treatment.
Important Considerations
Genetic Counseling: Genetic counseling is essential for families affected by MPS VI to understand the inheritance pattern and recurrence risk.
Multidisciplinary Care: Management of MPS VI requires a multidisciplinary team, including geneticists, metabolic specialists, orthopedists, cardiologists, pulmonologists, ophthalmologists, neurologists, and physical therapists.
Early Diagnosis and Treatment: Early diagnosis and initiation of enzyme replacement therapy can help to slow disease progression and improve outcomes.
Airway Management: Special attention to airway management is critical during anesthesia or any procedure that may compromise breathing.
Psychosocial Support: Providing psychosocial support to patients and families is essential to address the challenges of living with a chronic and progressive condition.
Research: Ongoing research efforts are focused on developing new and improved treatments for MPS VI.