MPS I. Hurler disease.
Incidence
1:100,000 . AR inheritance. It is a alpha-I-iduronidase deficiency
Clinical Characteristics
Appear normal at birth, except for repeated infections. Slow developm may be first manifestation. Abnormal bone by 1-2 yrs. Gargoyle appearance. Large hepatomegaly. Macrocephaly, dwarfism, protuberant abdomen, grotesque facial appearence, joint contractures Severe mental retardation, hypertelorism, dark coarse hair, splenomegaly in some, diastasis of recti muscles with freq. hernias. hirsutism, cloud corneas, pseudopapilledema, variable deafness, progres. heart disease. Marked skeletal deformities. Mucopolysaccharidosis I (MPS I) is a rare, autosomal recessive genetic disease that affects multiple organ systems and tissues. The disease is caused by a defect in the gene coding for the lysosomal enzyme alpha-L-iduronidase. As a result of this defect, the cells of people with MPS I are either unable to produce the enzyme or produce it in low amounts. MPS I is considered to be the prototypical lysosomal storage disorder with progressive multi-systemic disease and presenting features that vary depending on where a patient is on the disease continuum.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
EB(F), vacuolated lymphocytes and in basophilic cells in bone marrow, azurophilic granules in leukocytes, Urine metabolic screen with Berry test. MPS (HS & DS) in urine. The earlier diagnostic tests for the MPS disorders were based on the urinary excretion of glycosaminoglycans (MPS). Definitive diagnosis is established by alpha-L-iduronidase enzyme assay using artificial substrates (fluorogenic or chromogenic) in cultured fibroblasts or isolated leukocytes. Prenatal diagnosis is possible on both cultured amniotic fluid cells and chorionic villus biopsies.