Signs & Symptoms

Children with MPS III generally do not display overt features of the condition at birth.

Signs and symptoms of the disease typically begin to be recognized in early childhood, between 2- to 6-years-old, when the child starts missing developmental milestones.

The American Academy of Pediatrics suggests considering evaluation for inborn errors of metabolism (including MPS disorders) in children with neuromotor and global developmental delays.

Please consider ordering a urine MPS screening (non-sterile urine specimen) for your patients with developmental delay or a combination with any features listed below.

With the initiation of treatment trials, early diagnosis is key to giving children a lifeline to participate in clinical trials. We need your help identifying patients as early as possible.

Common Symptoms

Early Features:

  • Transient Tachypnea Of Newborn
  • Macrocephaly/J-Shaped Sella on Lateral Skull X-Ray
  • Recurrent Ear/Sinus Infections
  • Speech/Developmental Delays
  • Significant Hyperactivity
  • Autistic Symptoms
  • Diarrhea/Chronic Loose Stool
  • Poor Sleep
  • Umbilical Hernia

Later Features:

  • Progressive Intellectual Disability With Brain Atrophy
  • Seizures/Dystonia
  • Enlarged Liver/Spleen
  • Coarsening Facial Features (prominent eyebrows)
  • Hearing Loss (May Be Early)
  • Loss Of Ambulation
  • Loss Of Oral Feeding
  • Early Death

Photos of Children With Sanfilippo Syndrome

These photographs demonstrate the phenotype of Sanfilippo Syndrome.

Average Age at Diagnosis of Patients With Sanfilippo

Sanfilippo Type No. of Diagnoses+ Median Age (Range)++
Type A 31 3.5 (0.2-17.1)
Type B 17 3.5 (0.0-21.4)
Type C 3 10.7 (5.7-12.0)
Type D 4 3.1 (0.4-7.4)
+ Data are number of postnatal diagnoses made in each group for which age data were available. ++ In some instances, early diagnosis was facilitated by an older affected sibling as an index case. Age at diagnosis of 0.0 refers to individuals diagnosed in the first 2 weeks after birth
Source: Meikle PJ, Hopwood JJ, Clague AE, Carey WF (January 1999). “Prevalence of lysosomal storage disorders”. JAMA. 281 (3): 249–54. doi:10.1001/jama.281.3.249. PMID 9918480. https://pubmed.ncbi.nlm.nih.gov/9918480/