Muk is a cheerful, strong-willed and sensitive five-year-old girl. She has Sanfilippo type A (MPS IIIA), also known as childhood dementia. This rare, progressive metabolic disease prevents her body from properly breaking down certain substances. They build up, especially in the brain, causing Muk to gradually lose skills and abilities.

FAYUVI, formerly UX111, is FDA-approved. However, approval does not mean treatment is immediately available to Muk. First, it must be established whether FAYUVI is medically suitable and practically accessible for her, and how treatment will be funded. The final price, conditions and additional costs are not yet known. That is why Stichting Muk is continuing to raise funds, so it can act as soon as treatment becomes possible.

FAYUVI, formerly UX111, is a one-time gene therapy given through an infusion. It delivers a working copy of the SGSH gene to cells in the body. This gene helps cells produce the enzyme missing in Sanfilippo type A. The aim is to reduce the harmful build-up of substances and slow further decline. The FDA approved FAYUVI on 17 September 2026. Whether Muk can receive treatment, and what the outcome will be for her, cannot be guaranteed in advance. Read Ultragenyx’s explanation.

Research data give hope that FAYUVI may slow decline and help preserve important skills for longer. This could give Muk precious extra time in which she can remain herself as much as possible. The outcome for an individual child cannot be predicted in advance. That is why we deliberately describe a possibility, not a promise.

Sanfilippo is progressive, and damage that has occurred is irreversible. Each day without effective treatment may mean further decline. Now that FAYUVI is approved, we need to establish as quickly as possible whether, and how, treatment is available and medically suitable for Muk. Her parents want to be ready to act and avoid losing precious time.

FAYUVI is a specialised gene therapy for a very small group of patients. The final price, availability and conditions for Muk’s treatment journey are not yet known. The €1 million was therefore a preparatory target for treatment and everything that may be needed, such as medical preparation, travel and accommodation, guidance and unexpected costs. The final costs may be higher or lower. Once more is certain, Stichting Muk will publish a more detailed breakdown.

If FAYUVI does not become available to Muk or proves medically unsuitable, donations remain under Stichting Muk’s management. The board may only spend the funds within the foundation’s purposes as set out in its statutes, for example on another medically suitable treatment, essential care or support for Muk, or activities relating to childhood dementia and Sanfilippo. We will explain any significant change in how the funds are used as specifically as possible on this website. Money is not automatically transferred to another foundation.

The €1 million milestone has been reached, but the exact costs of Muk’s treatment, medical preparation, travel, accommodation, guidance and unexpected expenses are not yet known. That is why every donation still matters. Donations remain under Stichting Muk’s management and are only spent within its purposes as set out in its statutes. As more becomes clear, we will show what is needed and what the donations received make possible.

Donations are managed by Stichting Muk tegen Kinderdementie and may only be spent within its purposes as set out in its statutes. The first priority is to make a medically suitable treatment and the complete journey around it possible for Muk. This may also include necessary medical preparation, travel, accommodation, guidance, care and support. The foundation communicates transparently about significant changes.

The current total is shown on the donation page of this website. It changes regularly with new online donations, bank transfers and fundraising activities. That is why we do not give a fixed amount here that would quickly become out of date.

Go to the donation page to donate online through iDEAL, Bancontact, credit card, Apple Pay or PayPal. You can also make a direct bank transfer to NL81 RABO 0161 5260 04, account name Stichting Muk tegen Kinderdementie.

For a one-time online donation, we only ask for the details needed for payment and confirmation. We do not ask for an address or phone number if they are not needed. Our privacy policy explains which data are processed and how long they are kept.

Your name does not have to be made public. An electronic payment is not fully anonymous to the bank or payment provider, and the foundation may receive transaction details needed for its records.

Yes. Businesses can support Muk with a donation, fundraising activity, sponsorship or by sharing her story. A bank limit may apply to large amounts; a bank transfer is often simpler in that case. For personal contact or questions, email steun@stichtingmuk.nl.

Yes, absolutely. Sharing Muk’s story through Instagram, Facebook, WhatsApp or LinkedIn may reach someone who can donate, help or share it again. You can also organise a fundraiser, approach a business or tell others why every day matters for Muk.

Muk’s greatest chance lies in reaching as many people as possible. A single share can bring her story to someone who can make a difference. Social media also help keep donors and supporters informed about fundraising and important developments.

Stichting Muk tegen Kinderdementie and Stichting Sanfilippo Fonds are two separate legal entities, each with its own board, records, bank account and purpose. Stichting Muk focuses on Muk’s future. Stichting Sanfilippo Fonds has a broader purpose for children with Sanfilippo. Any contribution or transfer between the foundations is never automatic: it requires a separate, recorded board decision, and the spending must fit both foundations’ purposes. We communicate transparently about this.

Stichting Sanfilippo Fonds has held ANBI status since 30 October 2025 (RSIN 868618834). That status does not automatically apply to Stichting Muk. Through the donation form on this website, you donate to Stichting Muk tegen Kinderdementie (RSIN 868308778). Donations to Stichting Sanfilippo Fonds may be tax-deductible subject to conditions. View the ANBI details.

We share updates on this website and through Instagram, Facebook and LinkedIn. After an online donation, you also receive a thank-you email with a link to our social channels.