Can a Brain Implant Treat Dementia Caused by Sanfilippo Syndrome? A Boy’s Story Offers Hope

According to a story from, Harley Bond was three years old when he was first diagnosed with Sanfilippo syndrome type B, a rare progressive genetic disorder. Now five years old, the boy’s condition declined significantly since the diagnosis. One day, he stopped addressing his parents, Emma Siddal and Wayne Bond, after he forgot how they were. However, Harley saw improvement after participating in a very special clinical trial.

About Sanfilippo Syndrome

Sanfilippo syndrome, which is also known as mucopolysaccharidosis III, is rare genetic lysosomal storage disease. It is linked to a deficiency in the enzyme responsible for the breakdown of heparan sulfate. There are four different types of Sanfilippo syndrome and each one is caused by a different genetic mutation. In type A, the mutation affects the SGSH gene. The mutation caused is the only defining characteristic of the different types, which otherwise present similarly. Symptoms include behavioral abnormalities, dementia, sleep disturbances, difficulty speaking, developmental delays, deafness, and loss of movement. There are currently no disease modifying therapies available for this disorder. However, bone marrow replacement can be useful if implemented early. Most patients do not survive beyond their teenage years, but some can survive into their 30s. To learn more about Sanfilippo syndrome, click here.

Harley’s Story

Emma and Wayne couldn’t help but feel cut off from their son when it was clear that he didn’t know who they were and avoided eye contact. The trial involved 22 other patients with the disease who were treated with a chip implanted into the brain. This chip is able to release the enzyme that is missing in patients with Sanfilippo syndrome. As of now, the implant appears to be working. Harley saw improvements in his mobility and speech; in addition, he was able to recognize his parents again. 

While Harley still has some good days and some bad days, the implant appears to have halted the progression of his disease, at least for now. Any time in which the disease can be delayed or halted means prolonging the boy’s life.

Meanwhile, the family can hope that more impactful treatments can be developed in the meantime that can reverse the effects of the illness that Harley continues to deal with.

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