Columbia Neurology Treatment Helps Child with Rare Mitochondrial Disorder

Aries, a young boy diagnosed with thymidine kinase 2 (TK2) deficiency, a rare genetic disorder that causes progressive muscle weakness and respiratory failure, has made significant progress following treatment with a therapy developed at Columbia University.

Under the care of Columbia pediatric neurologist Valentina Emmanuele, MD, PhD, and Michio Hirano, MD, Aries began receiving the experimental medication through a compassionate use program in April 2025. Developed by Dr. Hirano through years of research at Columbia, the treatment provides essential building blocks needed to maintain mitochondrial DNA and prevent muscle degeneration. 

The therapy, now known as KYGEVVI, received FDA approval in November 2025.

Following treatment and comprehensive rehabilitation at Blythedale Children’s Hospital, Aries regained significant strength and motor function. By July 2026, he no longer required a tracheostomy, and he returned home to his family in August.

Blythedale recently featured Aries’ progress in an article, highlighting the combined contributions of Columbia's clinical and research teams and Blythedale's rehabilitation specialists.