Sanfilippo Syndrome

Reports from the MHC data base

Report from the Observation Chart (PDF)


MPS III (Mukopolysackaridos type III)


ICD-10: E76.2
ORPHA: 581

Estimated occurrence

1-2:1,000,000 inhabitants


The syndrome is caused by a mutation in the genes coding for four different enzymes that are involved in the breakdown of the mucopolysaccharide heparan sulfatase. Normally the breakdown occurs in the cell lysosome; however, in Sanfilippo syndrome, the mucopolysaccharides accumulate in the cells. This results in progressive damage to different bodily tissues and organs. Sanfilippo syndrome is inherited automsal recessively.

General symptoms

In Sanfilippo syndrome, mucopolysaccharides are stored primar ily in the nerve system. There are four different enzyme deficiencies that cause Sanfilippo syndrome and hence the syndrome is classified as type A, B, C or D.

Type A is considered the most severe form, type B consists of both a milder and more severe form, and type C is considered to lie between types A and B in severity. Type D is very uncommon. The children are born healthy and develop normally up to between 2 and 6 years of age, after which developmental disorders, such as delayed speech and language development, and autistic traits appear.

Extreme hyperactivity is common. Thereafter, a progressive deter ioration occurs. Gradually mental retardation becomes apparent. In the next phase, balance worsens, as well as the ability to walk and mental capabilities. Epilepsy may occur. Skeletal deformities and stiffness of the joints may occur. Respiratory tract infections are common. Ear infections may cause hear ing impairments. Abdominal/bowel problems are common. The accumulation of heparan sulfate inhibits blood coagulatation and thus afflicted persons have increased bleeding times.

Orofacial/odontological symptoms

Neurologic impairment may affect oral motor function, and speech development. Eating, drinking and swallowing difficulties are common. Poor muscle tonus of the lips and orofacial musculature may cause drooling. Bite, teeth and jaw may be expected to grow and develop normally.

Orofacial/odontological treatment

  • Early contact with dental services for evaluation and treatment planning is important. Prevention is important in their dental care. These patients require extra prophylactic care and should preferably be treated by the same dental personnel at each visit.
  • Risk exists for impaired coagulation and long bleeding times. This r isk should be examined and, if needed, be treated prior to impending tooth extraction or operations in the oral cavity.
  • Orofacial therapy and oral motor skills training and stimulation in cases of difficulties with eating, speech or drooling may be relevant.
  • Speech, language and communication training are often required.
  • Feeding and swallowing difficulties are investigated and treated by a specialist team at the hospital or multidisciplinary treatment center.


  • The rare disease database of the Swedish National Board of Health and Welfare.
  • The MHC database - The Mun-H-Center database on oral health and orofacial function in rare diseases.
  • The Documentation from the Ågrenska national competence centre for rare diseases.
Updated: 2017-09-13 08:26