Mucopolysaccharidosis Type I or Hurler Syndrome

Mucopolysaccharidosis Type I or Hurler Syndrome

Mucopolizaharidosis Type I belongs to the category of metabolic diseases caused by a deficiency of lysosomal enzymes, necessary for the breakdown of an important component of the extracellular matrix, the articular fluid and the connective tissues. Also called Hurler Syndrome, the condition causes a visceral (organ), bone and neurological suffering.
Children born with Type I mucopolysaccharidosis appear healthy at birth and have normal development initially. Although the diagnosis can be made at the age of 6 to 24 months of life, anomalies can be observed late.


Hurler syndrome is a rare disease, inherited genetically and caused by a gene mutation that causes lysosomal enzyme formation on chromosome 4. The lysosome is a cellular organism that stores over 40 enzymes that become active once they are released into the body.
The genetic defect underlying Type I mucopolysaccharidosis is the body's inability to produce the lysosomal enzymes (alpha-L-iduronidase) that metabolizes glycosaminoglycan (the basic structural component of articular, vertebral and collagen cartilage).
As a result, glycosaminoglycan accumulates in excess in lysosomes, ultimately causing dysfunction of cells, tissues and organs in the body. The disease occurs in 1 in 100,000 newborns.


Since the first 3 months of life, babies born with Hurler Syndrome may have recurrent groin and umbilical hernias, rhinitis or otitis. Up to 12 years of age, the symptoms of the disease are fully manifested:

  • deformations of the face: infiltrating features, prominent forehead, volume increase of the tongue;
  • short stature, with short trunk and neck;
  • deformations of the bone system (rigid fingers, hip dysplasia, etc.);
  • heart, lung and liver disorders;
  • frequent respiratory disorders (apnea);
  • corneal opacity, glaucoma;
  • poor hearing;
  • neurological disorders: mental retardation, poor language, etc.


Traditional medicine uses spinal transplantation as a type of treatment, but the results are uncertain and with high risks. Currently, there is also the variant of enzyme replacement therapy (TSE), administered weekly by infusion.
The control of the symptoms is done according to the clinical manifestations of the disease: hearing prosthesis, oxygen therapy, treatment of hernias and specific orthopedic treatments.
Prevention of the disease is possible before birth, by enzymatic or peach diagnosis, if the mutations existing in the family medical history are known.