Hurler syndrome

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Hurler syndrome
Synonyms	Mucopolysaccharidosis type I (MPS I), Gargoylism
Pronounce
Specialty	Medical genetics, Pediatrics
Symptoms	Developmental delay, coarse facial features, hepatosplenomegaly, corneal clouding, hearing loss
Complications	N/A
Onset	Infancy
Duration	Lifelong
Types	N/A
Causes	Genetic mutation in the IDUA gene
Risks	Autosomal recessive inheritance
Diagnosis	Genetic testing, urine test for glycosaminoglycans
Differential diagnosis	Hunter syndrome, Morquio syndrome, Sanfilippo syndrome
Prevention	N/A
Treatment	Enzyme replacement therapy, hematopoietic stem cell transplantation
Medication	N/A
Prognosis	Variable, often severe
Frequency	1 in 100,000 births
Deaths	N/A

Hurler syndrome (also known as Mucopolysaccharidosis type I, MPS I, or Hurler's disease) is a genetic disorder that results from the buildup of glycosaminoglycans (GAGs) due to a deficiency of the enzyme alpha-L-iduronidase. This enzyme deficiency leads to a range of symptoms and physical abnormalities.

Signs and Symptoms

Individuals with Hurler syndrome typically exhibit symptoms within the first year of life. Common signs and symptoms include:

• Developmental delay
• Coarse facial features
• Enlarged liver and spleen (Hepatosplenomegaly)
• Corneal clouding
• Joint stiffness
• Hearing loss
• Cardiac issues, such as valvular heart disease

Genetics

Hurler syndrome is inherited in an autosomal recessive manner. This means that an affected individual must inherit two copies of the defective gene, one from each parent. The gene responsible for Hurler syndrome is located on chromosome 4p16.3 and encodes the enzyme alpha-L-iduronidase.

Diagnosis

Diagnosis of Hurler syndrome is typically based on clinical presentation and confirmed through enzyme assay tests that measure the activity of alpha-L-iduronidase. Genetic testing can also identify mutations in the IDUA gene.

Treatment

There is no cure for Hurler syndrome, but treatments are available to manage symptoms and improve quality of life. These include:

• Enzyme replacement therapy (ERT) with laronidase
• Hematopoietic stem cell transplantation (HSCT)
• Symptomatic treatments, such as surgeries for heart and skeletal issues

Prognosis

The prognosis for individuals with Hurler syndrome varies. Without treatment, life expectancy is significantly reduced, often not extending beyond the first decade of life. With early intervention, particularly with HSCT, some individuals may live into adolescence or adulthood.

History

Hurler syndrome was first described by German pediatrician Gertrud Hurler in 1919. It is one of several types of Mucopolysaccharidosis disorders, which are collectively known as lysosomal storage diseases.

See Also

• Mucopolysaccharidosis
• Lysosomal storage disease
• Enzyme replacement therapy
• Hematopoietic stem cell transplantation

See also

• Mucopolysaccharidosis
• Lysosomal storage disease
• Enzyme replacement therapy
• Hematopoietic stem cell transplantation