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Ultragenyx exercises exclusive option to acquire GeneTx in order to further advance development of GTX-102 for the treatment of Angelman syndrome 

(AUSTIN, TX, July 18, 2022) -- The Foundation for Angelman Syndrome Therapeutics (FAST) today announced that Ultragenyx Pharmaceutical Inc. has exercised its exclusive option to acquire  GeneTx Biotherapeutics LLC, a biotechnology company founded and launched by FAST, and has closed on the acquisition. Since 2019, GeneTx and Ultragenyx have been partnered on the clinical development of GTX-102. The acquisition signals a critical step forward in support of FAST’s mission to foster the development of treatments for Angelman syndrome (AS), a rare and debilitating neurogenetic disorder that impacts approximately 1 in 15,000 individuals. 

There are currently no approved treatments for people with AS, who generally have no verbal language, experience motor and cognitive impairments, and live with debilitating seizures, among many other symptoms. AS presents serious challenges for individuals, their caregivers and families given the need for vigilant care. Because of the urgent need for meaningful therapeutics, FAST drives collaboration and sharing across research institutions, clinicians and industry, as well as other global organizations, to expedite the development of potential treatments.

In 2017, FAST launched GeneTx Biotherapeutics to develop an investigational antisense oligonucleotide, GTX-102, for the treatment of AS. This was based on extensive research by FAST’s integrated academic research initiative, which included study of a unique region on the UBE3A-ATS transcript, which had important implications in unsilencing, and therefore turning on, the UBE3A gene on the paternal copy.  

In 2019, GeneTx and Ultragenyx formed a partnership to develop GTX-102 and have since initiated a Phase 1/2 clinical study in the United States, the United Kingdom and Canada. 

“What happened today is why FAST was founded, why we started GeneTx, and why we donate and fundraise: To discover and accelerate promising therapies for AS,” said John Schlueter, chairperson of the board of FAST. “Our approach, from funding frontline discoveries through preclinical studies, to forging strategic partnerships in the biotechnology industry, aims to quickly advance translational research, so that families living with AS move closer to potentially transformative treatments.”  

As the largest non-governmental funder of AS research, FAST has consistently set the pace and direction of research into this condition. For years, FAST has convened multidisciplinary teams of scientists from top research universities and pharmaceutical companies to develop and fast-track potential therapeutics. From these efforts, FAST became the first rare-disease patient organization to launch a biotechnology start-up company to develop an investigational antisense oligonucleotide as a potential treatment for AS. 

With the proceeds from the sale of its shares of GeneTx, FAST is now able to pledge millions of dollars to be used directly to supercharge numerous pathways and promising programs, and in the process enrich the entire landscape of AS-related therapeutic research. 

Dr. Allyson Berent, chief science officer for FAST, stated, "we are most grateful to the entire Angelman syndrome community, our phenomenal scientific team, and our incredible families who work tirelessly to help raise the funds to advance these promising developments in AS research. The effort it takes to make a difference in the therapeutic landscape for those living with Angelman syndrome has been a journey of a lifetime, and this is an exciting milestone in the journey.”

About Angelman Syndrome

Angelman Syndrome is a rare genetic disorder characterized by developmental delays, epilepsy, and problems with motor coordination and balance. Individuals with AS do not develop functional speech. The seizure disorder in individuals with Angelman Syndrome can be difficult to treat. Feeding disorders in infancy are common, and some persist throughout childhood. Sleeping difficulties are commonly noted in individuals with Angelman Syndrome. AS affects approximately one in 15,000 births.  For more information about Angelman Syndrome, please visit

About FAST

FAST is a Section 501(c)(3) non-profit research organization narrowly focused on funding research that holds the greatest promise of treating Angelman Syndrome.   FAST is the largest, non-governmental funder of Angelman specific research.

To learn more about FAST's mission and funding priorities, or to make a donation towards FAST's research program visit