DOCTORS FEARED A RARE GENETIC DISEASE WOULD TAKE AWAY HIS ABILITY TO MOVE — NOW, THIS LITTLE BOY IS BACK HOME

When Priscilla noticed that her son Aries could not sit up independently at seven months old, she initially hoped he was simply developing at his own pace. But as the months passed, his muscle weakness became increasingly concerning, eventually leading his family into a medical journey that would change their lives.

Aries was diagnosed with thymidine kinase 2 deficiency, or TK2d, an extremely rare genetic disorder that affects the body’s ability to maintain mitochondrial DNA. The disease can cause progressive muscle weakness and respiratory failure. At one point, Aries needed breathing support and a tracheostomy to help him survive.

Today, after receiving a treatment developed through years of scientific research and undergoing intensive rehabilitation, Aries has made significant progress. In August 2026, he returned home to his family with new possibilities ahead.

A Rare Disease That Progressively Weakens the Body

Aries’s difficulties became more noticeable during his first year. He struggled to sit independently, and his muscle tone was unusually low. When his mother sought a second medical opinion in February 2025, he was referred to NewYork-Presbyterian Morgan Stanley Children’s Hospital for further evaluation.

Genetic testing confirmed TK2 deficiency, a rare mitochondrial disorder affecting fewer than two people per million worldwide. The condition can interfere with the body’s ability to maintain mitochondrial DNA, which is essential for cells to produce the energy needed for normal function.

For children who develop symptoms during infancy, the disorder can be particularly severe. Without effective treatment, progressive weakness may affect movement, swallowing and breathing. Aries’s condition deteriorated rapidly, leaving his family facing an uncertain future.

When Breathing Became a Daily Challenge

Aries spent approximately a month at the New York hospital before being transferred to Blythedale Children’s Hospital in March 2025 for specialized rehabilitation and respiratory support.

His condition was complex. He struggled to breathe independently and required BiPAP support. As his respiratory difficulties worsened, doctors performed a tracheostomy to help him breathe and placed a gastrostomy tube to provide nutrition.

For his mother, watching her son lose physical abilities was devastating. The medical team described how he remained alert and responsive even when his muscles were too weak to allow him to move normally.

A Treatment Developed Through Years of Research

While searching for options, Aries’s family learned about a treatment being developed by researchers at Columbia University Irving Medical Center. Under the care of pediatric neurologists Valentina Emmanuele and Michio Hirano, Aries began receiving the medication through a compassionate-use program in April 2025.

The therapy, now known as KYGEVVI, contains doxecitine and doxribtimine. It supplies building blocks needed to help maintain mitochondrial DNA in people with TK2 deficiency.

The treatment received approval from the U.S. Food and Drug Administration in November 2025. Clinical evidence showed a substantial reduction in mortality among patients whose muscle weakness began at age 12 or younger, although individual outcomes can vary.

Small Steps Turn Into Meaningful Progress

Medication was only one part of Aries’s recovery. At Blythedale, he participated in daily occupational, physical, speech and feeding therapies designed to help him regain strength and develop new skills.

At first, therapy sessions were short and carefully paced. He practiced sitting for a few minutes at a time, resting and then trying again. Therapists used toys and activities that interested him to encourage movement and interaction.

Gradually, Aries began making progress. He learned to recognize letters and fruits, turn the pages of a book and identify animals. His ability to sit, move and communicate continued to improve as his strength returned.

Leaving the Hospital and Returning Home

By July 2026, Aries had improved enough to come off the ventilator and have his tracheostomy removed. He no longer needed the breathing tube, although he continued to receive supplemental nutrition through his gastrostomy tube while working toward independent feeding.

In August, he was discharged from Blythedale and returned home to his family. The milestone marked a dramatic change from the child who had once struggled to breathe without support.

Aries still needs ongoing medical care, rehabilitation and monitoring. His journey is not a complete recovery from the disorder, and his progress cannot guarantee the same result for every child with TK2 deficiency.

A New Chapter for Aries and His Family

For Aries’s family, returning home represents more than leaving the hospital. It means being able to focus on family life while continuing the work of helping him grow stronger and develop new abilities.

His story also demonstrates the importance of collaboration between scientific researchers, doctors, rehabilitation specialists and families. Advances in treatment can be especially meaningful for rare disorders, where options have historically been limited.

Aries’s future remains a journey of gradual progress, but the changes he has already achieved are significant. From struggling to breathe and move to returning home with his family, his experience offers hope that new treatments and comprehensive rehabilitation can help children with rare diseases reach milestones that once seemed out of reach.

Source: Columbia University Irving Medical Center and Blythedale Children’s Hospital