Sophie Thomas, Interim chief executive of The MPS Society said: “Ultimately, recognition would help professionals understand the condition, it would improve access to support, encourage investment in research and make sure childhood dementia is considered in policy and service planning.”

A DHSC spokesperson said: “Neurodegenerative conditions such as Sanfilippo syndrome have a devastating impact and our thoughts are with Leni and her family.

“We are making sure patients with rare diseases get a definite diagnosis faster, while improving access to specialist care, treatment and drugs.

“At the same time we are working hard to find new ways to slow down the progress of dementia, speed up diagnosis and improve our understanding of the disease.”

Meanwhile, for Leni, there is a possibility of taking part in a clinical trial later this year.

Emily said: “For the first time since Leni’s diagnosis we actually have some hope for the future.

“We have received such a huge amount of support and generosity from people and there is now real hope of Leni accessing a clinical trial that could change her life.”

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