Options for testing for Sanfilippo Syndrome
Page reviewed by: Dr. Cara O’Neill, FAAP
Page last updated: August 8, 2022
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Early testing for Sanfilippo syndrome is crucial. Delays in diagnosis could impact access to clinical trials and/or services to support a child with Sanfilippo syndrome.
The American Academy of Pediatrics suggests considering evaluation of inborn errors of metabolism (including MPS disorders) in children with neuromotor and global developmental delays.
The American College of Medical Genetics and Genomics strongly recommends exome and genome sequencing as a first or second-tier test for children with congenital anomalies that onset by age 1, as well as those with developmental delay or intellectual disability that occurs by age 18.
Initial Testing Options for Sanfilippo Syndrome
Urine MPS Test
Traditionally, the initial test used to screen for Sanfilippo syndrome is the Urine MPS (glycosaminoglycans) Analysis, which detects if an abnormal amount of heparan sulfate is present in a child’s urine. (Of Note: This test is not part of a typical urinalysis used for determining infection.) Your physician may order a “Urine MPS Analysis” if there are concerns about Sanfilippo syndrome.
This test requires that a urine specimen be collected at home or at the medical office. It does not have to be a sterile collection. A first-of-the-morning urine sample is ideal, but not required. If the minimum of 3 mLs of urine is not collected at one time, you may combine more than one urine sample from the same day. If collected at home, the sample should be labeled, refrigerated, and taken directly to the physician or laboratory as directed.
While urine testing is still an important part of the diagnostic process, false negatives can occur. New screening methods are becoming more common as first-line tests (see below for details).
Many labs offer this test, the following is an example of one.
Genetic Panel Test
Genes for Sanfilippo may be tested by sampling blood, a cheek swab, or a saliva collection.
No-charge genetic testing and counseling for lysosomal storage diseases is available through Invitae. Results take an average of 10 to 21 days after Invitae receives the specimen. The preferred specimen is 3mL of whole blood.
Invitae’s test analyzes up to 53 genes, screening for 20 different lysosomal storage diseases, including Sanfilippo.
Flyer to take to your doctor. Download informational flier to share with your doctor.
Follow-Up Testing to Confirm Sanfilippo
Enzyme Activity Test
If suspicion remains after a negative urine test or of the Urine MPS Test or Gene Panel Test are positive, the diagnosis should be confirmed with a blood enzyme panel.
A blood enzyme assay is considered the most-credible diagnostic tool in testing for Sanfilippo Syndrome because it detects whether or not one of the enzymes in the cellular pathway that breaks down heparan sulfate is missing (the functional cause of Sanfilippo Syndrome), providing a definitive answer.
This test requires a blood draw. Usually from the arm.
Note: This blood enzyme test is ideal for younger patients with whom collecting a viable urine sample for the Urine MPS Screening is difficult or impossible.
Sanfilippo Syndrome is currently not included on any state’s newborn screening public health program. However, supplemental screening tools are available.
Face2Gene is a suite of phenotyping applications that facilitate comprehensive and precise genetic evaluations.
The Face2Gene Clinic app detects phenotypes of more than 7,500 genetic disorders, including Sanfilippo Syndrome, from facial photos a practitioner uploads, automatically calculates anthropometric growth charts, and suggests likely phenotypic traits to assist in feature annotation.
A clinician can review relevant syndrome phenotypes matches to genetic disorders based on gestalt and refine relevance of genetic disorders based on deep phenotyping.
Review the phenotypic traits of Sanfilippo Syndrome.