A Natural History Study of Sanfilippo Syndrome Type D

Sanfilippo syndrome type D is a ultra rare syndrome with limited available natural history data. This study is planned to document, through retrospective and prospective data collection, syndrome progression in children and young adults with Sanfilippo syndrome type D. The results from this study may inform future clinical studies in targeted therapies for patients with Sanfilippo syndrome type D and may serve as an external control since there are very few patients with Sanfilippo syndrome type D.

Inclusion Criteria:To be eligible to participate in the study, patients must meet all of the following criteria:Confirmed diagnosis of Sanfilippo syndrome type D disease by all of the following:Deficiency in alpha-GNS enzyme activityHas presented with signs/symptoms consistent with Sanfilippo syndrome type D, or, for individuals who have not presented with signs/symptoms of disease (eg, siblings of known patients), the determination of eligibility will be at the discretion of the Sponsor in conjunction with the site InvestigatorGenomic DNA analysis demonstrating homozygous or compound heterozygous, pathogenic and/or potentially pathogenic variants in the GNS geneAccumulated GAG HS in urineWritten informed consent from parent or legal guardian and assent from patient, if requiredParent/legal guardian willing to accompany the patient to all study visitsAbility to comply with protocol requirements, in the opinion of the InvestigatorNegative urine pregnancy test at screening (nonsterile females of childbearing potential only) -Exclusion Criteria:Patients who meet any of the following criteria will not be eligible to participate in the study:Have received an investigational drug within 30 days prior to the Baseline VisitConcomitant illness or medical condition or extenuating circumstance that, in the opinion of the Investigator, might compromise the patient's ability to comply with protocol requirements, the patient's well-being or safety, or the interpretability of the patient's clinical dataThe presence of significant non-MPS IIID-related CNS impairment or behavioral disturbances that would confound the scientific rigor or interpretation of results of the study -