Sanfilippo syndrome is the most common disorder of a much larger family of rare, progressive, genetically inherited metabolic disorders. The severe, more common manifestation of the disease begins with Phase 1, which typically emerges between ages 1 and 3 years as patients exhibit a slowing or plateauing of cognitive development, with speech most often affected. An enlarged liver or mildly course facial features are also common symptoms. At approximately ages 3 to 4 years, in Phase 2, patients start to show progressive cognitive degeneration, behavioral and sleep difficulties, and obstinacy and autistic-like behaviors, all of which become more pronounced and worsen over time. The 3rd phase is devastating. It usually manifests in the teenage years with severe dementia, motor function decline, and the disappearance of behavioral problems as patients lose locomotion and have problems swallowing. Spasticity also emerges. Eventually patients regress to a bedridden, vegetative state and die in their late 20s or early 30s. In the milder or attenuated form of the syndrome, disease progression is more gradual and longer survival is seen; however, this attenuated form is less common.
Sanfilippo syndrome is 1 of 7 mucopolysaccharidoses, disorders that involve protein‒carbohydrate complexes and their metabolism. These disorders are part of an even larger family of lysosomal storage disorders. Sanfilippo syndrome has 4 subtypes, A, B, C, and D, each of which is caused by a different enzyme deficiency. The commonality is that each of these enzymes is involved in metabolizing heparan sulfate. Incompletely broken down heparan sulfate remains stored in cells in the body causing progressive damage, and although babies may show few signs of disease early on, symptoms emerge as more cells become damaged. Subtypes A and B are more common than C and D. There is usually little difference between disease subtypes with regard to symptoms and disease course; however, very mild cases of subtype B disease have been observed where affected patients have maintained relative health into adult life.
Currently there is no cure for Sanfilippo syndrome, but an enzyme replacement therapy clinical trial for early-stage pediatric subtype A is ongoing and recruiting patients (see NCT02060526 at clinicaltrials.gov). Although treatment with bone marrow transplantation has yielded disappointing results, research is ongoing in gene therapy, molecular chaperone therapy, and intrathecal enzyme therapy. Gene therapy appears to be the most promising.
About the Connexion Healthcare Rare Disease Center of Excellence
The Connexion Healthcare Rare Disease Center of Excellence specializes in communicating the science behind rare diseases and orphan drugs. We strategically partner with industry leaders in the rare disease community to proactively connect all stakeholders in launching products to underserved patient populations. Our team comprises specially skilled communications experts who plan, develop, and disseminate scientific communications based on their advanced knowledge of the science, the patient journey, healthcare providers, and the orphan drug approval process.
Our cross-functional teams navigate complicated treatment and market landscapes by elucidating the appropriate pathways to brand success. We understand how brand strategy drives market share. Since launching its dedicated Rare Disease Center of Excellence, Connexion has developed pre-launch, launch, and postlaunch communications in numerous rare congenital and genetic disorders, movement disorders, metabolic disorders, lysosomal storage disorders, lung diseases, blood diseases, skin diseases, endocrine diseases, and rare cancers.
For further information regarding the Rare Disease Center of Excellence at Connexion Healthcare and how we can develop rare disease communications to differentiate therapies by their unique attributes, contact:
Susan Stein, MPH
Robert M. Francomano
Senior Vice President
Rare Disease Center of Excellence