Hurler syndrome is an inherited disease that belongs to a group of diseases called mucopolysaccharidoses. Storage of abnormal quantities of this material (mucopolysaccharide) in different body tissues is responsible for the symptoms and appearance of the disease.
Alternative Names
Alpha-L-iduronate deficiency (formerly gargoylism)
Causes, incidence, and risk factors
Hurler syndrome is inherited as an autosomal recessive trait. The metabolic defect that causes Hurler syndrome is the body's inability to make an enzyme called lysosomal alpha-L-iduronate. Approximately 1 in 150,000 infants are affected. Newborn infants with this defect appear normal at birth but, by the end of the first year, signs of impending problems begin to develop. The children slowly develop coarse, thick, facial features, prominent dark eyebrows, cloudy corneas, progressive stiffness, and obvious mental retardation . The disease damages many organs including the heart and heart valves. In the early onset form of the disease, death occurs in the early teens, often from the associated heart disease .
Signs and tests
HepatomegalySplenomegalyInguinal hernia Flared nostrils Epicanthal folds Enlarged tongue Retinal pigmentation Hip dislocation
Vertebral wedging KyphosisHeart murmurs Heart valve damage from thickening Tests that may indicate the syndrome is present include:
Increased excretion of dermatan sulfate and heparan sulfate in the urine Absence of lysosomal alpha-L-iduronidase (in cultured fibroblasts) Culture of cells from amniotic fluid obtained by amniocentesis for enzyme testing (prenatal testing)
Abnormal histologic staining of white blood cells called metachromasia X-ray of the skeletonX-ray of the spineX-ray of the chestECG
Support groups
National MPS Society, Inc. 610-942-0100; www.mpssociety.org
Expectations (prognosis)
Hurler syndrome is a disease with a poor prognosis. Children with this disease have significant progressive physical and mental deficiencies. Death can occur in late childhood, early adolescence , or adulthood.
Calling your health care provider
Call your health care provider if you have a family history of Hurler syndrome and are considering having children, or if your child begins to develop a group of the characteristic signs and symptoms of Hurler syndrome.
Prevention
Genetic counseling is important for prospective parents with a family history of Hurler syndrome. In addition, tests are available for the prenatal diagnosis of Hurler syndrome. The test consists of an amniocentesis and collection of amniotic fluid . Cells in the amniotic fluid are then cultured and the a-L-iduronidase activity in the cells is determined.