Taysha Gene Therapies Reports First Quarter 2022 Financial Results and Provides Corporate Update Initiated clinical development of TSHA-102 for Rett Syndrome under recently approved Clinical Trial Application (CTA) with

Taysha Gene Therapies Reports First Quarter 2022 Financial Results and Provides Corporate Update

Initiated clinical development of TSHA-102 for Rett Syndrome under recently approved Clinical Trial

Application (CTA) with preliminary Phase 1/2 data expected by year-end 2022

Drug Designation from the European Commission for TSHA-120 for giant axonal neuropathy (GAN) and recently completed commercially representative GMP batch; regulatory update expected in mid-2022

Existing cash and cash equivalents, along with full access to the term loan facility, is

expected to fund operating expenses and capital requirements into the fourth quarter of 2023

Dallas May 16, 2022 -

Taysha Gene Therapies, Inc. (Nasdaq: TSHA), a patient-centric, pivotal-stage gene therapy company focused on developing and commercializing AAV-based gene therapies for the treatment of monogenic diseases of

the central nervous system (CNS) in both rare and large patient populations, today reported financial results for the first quarter ended March 31, 2022 and provided a corporate update.

In 2022, we are focused on advancing our key programs in Rett syndrome and GAN. We initiated clinical development of TSHA-102 in Rett syndrome and

expect preliminary clinical data from the REVEAL study by year-end, said RA Session II, President, Founder and CEO of Taysha. Recently, the European Commission granted orphan drug designation for TSHA-120 for GAN, further highlighting

the unmet need for treatment options for these patients and the important potential of TSHA-120. We have completed a commercially representative GMP batch for TSHA-120 with release testing currently underway. Our existing capital resources, along

with full access to the term loan facility, should fund operating expenses and capital requirements into the fourth quarter of 2023.

Corporate Highlights

TSHA-120 for giant axonal neuropathy (GAN): an intrathecally dosed AAV9 gene

therapy currently being evaluated in a clinical trial for the treatment of GAN, a rare inherited genetic disorder that affects both the central and peripheral nervous systems and is caused by loss-of-function mutations in the gene coding for gigaxonin. TSHA-120 is designed to deliver a functional copy of the GAN gene to the CNS and PNS. TSHA-120 has already received orphan drug and rare pediatric disease designations from the U.S. Food and Drug Administration (FDA) and orphan drug designation from the European Commission.

syndrome: a self-complementary intrathecally delivered AAV9 gene replacement therapy under development for the treatment of Rett syndrome. TSHA-102 utilizes the novel miRARE platform to

regulate transgene expression genotypically on a cell-by-cell basis. TSHA-102 is the first-and-only gene therapy in clinical development for Rett syndrome. TSHA-102 has received orphan drug and rare pediatric disease designations from the FDA and has

been granted orphan drug designation from the European Commission.

AAV9 Gene Replacement for CLN7 Batten disease: an investigational AAV9

intrathecally dosed gene replacement therapy designed to deliver a full-length copy of the CLN7 gene to potentially treat CLN7 disease, a rapidly progressing rare lysosomal storage disease with no approved treatments. The clinical development

of the CLN7 program is being funded by UT Southwestern (UTSW), Children s Health and Children s Medical Center Foundation.

Anticipated Milestones

First Quarter Financial Highlights

Research and Development (R&D) Expenses: Research and development expenses were $37.8 million for the three months ended March 31, 2022,

compared to $23.9 million for the three months ended March 31, 2021. The increase of approximately $13.9 million was primarily attributable to an increase of $9.3 million in employee compensation, which included $2.2 million

of severance and one-time termination costs in connection with the strategic reprioritization of programs completed in March 2022 and $1.0 million of non-cash

stock-based compensation. Additionally, in the three months ended March 31, 2022 we incurred an increase of $2.9 million of expenses in research and development manufacturing and other raw material purchases. We also incurred an increase

of $1.7 million of third-party research and development consulting fees, primarily related to GLP toxicology studies and clinical study activities.

General and Administrative (G&A) Expenses: General and administrative expenses were $11.5 million for the three months ended

March 31, 2022, compared to $8.2 million for the three months ended March 31, 2021. The increase of approximately $3.3 million was primarily attributable to $2.9 million of incremental compensation expense, which included

$0.4 million of severance and one-time termination costs and $0.7 million of non-cash stock-based compensation. We also incurred an increase of

$0.4 million in professional fees related to insurance, investor relations/communications, accounting, and market research.

loss: Net loss for the three months ended March 31, 2022 was $50.1 million, or $1.31 per share, as compared to a net loss of $32.0 million, or $0.87 per share, for the three months

ended March 31, 2021.

Cash and cash equivalents: As of March 31, 2022, we had $96.6 million in cash and cash equivalents. This

excludes approximately $12 million in gross proceeds generated from the sale of common stock, par value $0.00001 per share, under our existing at-the-market

facility in April 2022.

Conference Call and Webcast Information

Taysha management will hold a conference call and webcast today at 8:00 am ET / 7:00 am CT to review its financial and operating results

and to provide a corporate update. The dial-in number for the conference call is 877-407-0792 (U.S./Canada) or 201-689-8263 (international). The conference ID for all callers is 13729044. The live webcast and replay may be accessed by visiting Taysha s website

at https://ir.tayshagtx.com/news-events/events-presentations. An archived version of the webcast will be available on the website for 30 days.

About Taysha Gene Therapies

Taysha Gene Therapies (Nasdaq: TSHA) is on a mission to eradicate monogenic CNS disease. With a singular focus on developing curative medicines, we aim to

rapidly translate our treatments from bench to bedside. We have combined our team s proven experience in gene therapy drug development and commercialization with the world-class UT Southwestern Gene Therapy Program to build an extensive, AAV

gene therapy pipeline focused on both rare and large-market indications. Together, we leverage our fully integrated platform an engine for potential new cures with a goal of dramatically improving patients lives. More information is

available at www.tayshagtx.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as

anticipates, believes, expects, intends, projects, plans, and future or similar expressions are intended to identify forward-looking statements. Forward-looking

statements include statements concerning the potential of our product candidates, including our preclinical product candidates, to positively impact quality of life and alter the course of disease in the patients we seek to treat, our research,

development and regulatory plans for our product candidates, the potential for these product candidates to receive regulatory approval from the FDA or equivalent foreign regulatory agencies, and whether, if approved, these product candidates will be

successfully distributed and marketed, the potential market opportunity for these product candidates, our corporate growth plans, the forecast of our cash runway and the implementation and potential impacts of our strategic pipeline prioritization

initiatives. Forward-looking statements are based on management s current expectations and are subject to various risks and uncertainties that could cause actual results to differ materially and adversely from those expressed or implied by such

forward-looking statements. Accordingly, these forward-looking statements do not constitute guarantees of future performance, and you are cautioned not to place undue reliance on these forward-looking statements. Risks regarding our business are

described in detail in our Securities and Exchange Commission ( SEC ) filings, including in our Annual Report on Form 10-K for the full-year ended December 31, 2021 and our Quarterly Report on

Form 10-Q for the quarter ended March 31, 2022, both of which are available on the SEC s website at www.sec.gov. Additional information will be made available in other filings that we make from time to time with the SEC. Such risks may be

amplified by the impacts of the COVID-19 pandemic. These forward-looking statements speak only as of the date hereof, and we disclaim any obligation to update these statements except as may be required by law.

Taysha Gene Therapies, Inc.

Condensed Consolidated Statements of Operations

(in thousands, except share and per share data)

Taysha Gene Therapies, Inc.

Condensed Consolidated Balance Sheet Data

(in thousands, except share and per share data)

Chief Corporate Affairs Officer

Taysha Gene Therapies

Canale Communications