Benjamin was diagnosed shortly after he was born, on December 23, 2024, with neonatal-onset ornithine transcarbamylase deficiency, or OTC deficiency, a rare genetic disorder that prevents the body from clearing ammonia from the blood. Without urgent treatment, ammonia can rise to dangerous levels, especially in newborns. In severe cases, liver transplant is the only cure.
For Carstens and Benjamin's mother, Karla Hernandez Garcia, timing still feels surreal. August 18 had always been the day they celebrated Carstens's birthday. Now, it is also the day Benjamin was given the gift of life—a day the family will carry with them forever.
"When we were told Benjamin needed a liver transplant, we learned that living donor transplants are associated with better outcomes. There was no question," said Carstens. "If I could donate to save him, I was going to do it."
Now, as the family looks ahead to the first anniversary of Benjamin's transplant this August, they are settling into everyday routines that once felt uncertain.
Born With a Rare Metabolic Liver Condition: OTC Deficiency
OTC deficiency affects the way the body processes protein. In healthy bodies, ammonia—a waste product created when protein is broken down—is cleared from the blood. In babies with severe OTC deficiency, ammonia can build up quickly and affect the brain and other organs.
Benjamin was transferred to the Pediatric Liver Transplant Program at Hassenfeld Children's Hospital for specialized care, where teams worked closely with Benjamin's primary specialists to guide him safely to liver transplantation.
"We were referred to Hassenfeld Children's Hospital's Pediatric Liver Transplant team because of the exceptional expertise and reputation for performing highly complex, precise surgeries," said Carstens. "At just 7 months old, because of his size, Benjamin required extraordinary technical skill and attention to detail. We knew there was no better place for his care."
"OTC deficiency can progress very quickly in newborns, and Benjamin needed highly specialized care from the start," said Jennifer M. Vittorio, MD, pediatric hepatologist and medical director of the Pediatric Liver Transplant Program. "His care required urgent metabolic management, close monitoring, and coordination across pediatric hepatology, transplant surgery, intensive care, anesthesia, nursing, and many other teams."
For Carstens and Hernandez Garcia, Benjamin's diagnosis changed the course of their first year with him. Instead of settling into life at home with a newborn, they were learning how to manage a rare condition, what undergoing a transplant would involve, and what it would take to get Benjamin strong enough for surgery.
A Father and Son Transplant
As Benjamin continued to receive care, Carstens was evaluated through NYU Langone's Living Donor Transplant Program and found to be a perfect match.
Living donor liver transplant allows a healthy individual to give a portion of their liver to someone who needs a transplant. Because the liver has a unique ability to regenerate, both the donor's remaining liver and the transplanted portion can grow and restore themselves over time. For infants and young children, living donation can also allow the care team to plan the timing of surgery—especially important in Benjamin's case, given his diagnosis of OTC deficiency.
"For families facing pediatric liver transplant, the process can feel overwhelming, especially when a child has already spent considerable time in the hospital," said Dana L. Goldner, MD, Benjamin's primary pediatric hepatologist and a member of the Pediatric Liver Transplant Program at Hassenfeld Children's Hospital. "Our role is to help families understand each step, prepare for transplant, and feel supported through recovery and transition home."
On August 18, Carstens underwent a minimally invasive robotic surgery at NYU Langone, led by Karim J. Halazun, MD, surgical director of the Adult Liver Transplant Program, to remove a small portion of his liver for donation to Benjamin.
"Living donation begins with a healthy person making an extraordinary decision to undergo surgery for someone else," said Dr. Halazun. "Our role is to make the donor surgery as safe and carefully planned as possible while coordinating closely with the pediatric team caring for the child receiving the transplant."
Benjamin's transplant was successfully performed by Adam Griesemer, MD, surgical director of the Pediatric Liver Transplant Program and director of NYU Langone's Living Donor Liver Transplant Program, and pediatric transplant surgeon Bernardo Daniel Campos, MD.
Carstens was able to see Benjamin in the Pediatric Intensive Care Unit at Hassenfeld Children's Hospital during their recovery the day after surgery.
"For very young patients like Benjamin, living donor liver transplant can allow us to move forward at the right time, with the right teams in place," said Dr. Griesemer. "Seeing Benjamin growing and doing well today is why we do this work."
While Carstens's donation gave Benjamin a second chance at life, Hernandez Garcia played an equally vital role in helping him recover. A registered nurse who was working at NYU Langone Hospital—Long Island at the time of Benjamin's transplant, Hernandez Garcia took a leave of absence to care for both Benjamin and Carstens during the critical weeks surrounding post-surgery. Her clinical training helps her navigate the complexity of Benjamin's recovery, from medication and appointments to the daily demands of his care at home.
A Tiny Surgeon Costume During Recovery
Benjamin continued to receive care at Hassenfeld Children's Hospital after the transplant, and the family formed strong bonds with the care team, including certified child life specialists and Katie Sclafani, a pediatric liver transplant social worker. The care team helped provide emotional support during the process and recovery while ensuring a smooth transition home. These services are provided by Sala Institute for Child and Family Centered Care.
During Benjamin's recovery, his family found ways to mark moments outside of his medical care alongside the care team. For Halloween, Hernandez Garcia worked with Sala's certified child life specialists to dress Benjamin as "Baby Dr. Adam Griesemer," complete with a tiny white coat and badge honoring his transplant surgeon.
The costume became one of the family's most memorable experiences from Benjamin's recovery, and a meaningful one for the team caring for him.
Home and Honored at the New York City Liver Life Walk
Benjamin went home in December 2025, just before his first birthday. He is now approaching the first anniversary of his transplant this August.
The family recently joined Benjamin's pediatric liver team at the American Liver Foundation's Liver Life Walk New York City at Chelsea Piers, where Benjamin and his father were recognized as LIVEr Co-Champions. The honor represents how far father and son have come since Benjamin's diagnosis and transplant.
"Seeing Benjamin at home with his family and reaching milestones after the transplant is exactly what we hope for when we care for children with complex liver disease," said Dr. Vittorio. "His progress reflects not only the transplant itself, but the months of care, preparation, and family support that helped him get there."
In August, the family hopes to gather with loved ones for a celebration of Benjamin's first transplant anniversary and Carstens's 29th birthday. This year also brings more milestones for the family. Carstens and Hernandez Garcia, two high school sweethearts, plan to get married, now with their healthy son in attendance.
For Carstens, this Father's Day is a chance for the family to recognize what it took to get Benjamin home, and what they now have to look forward to together.
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SOURCE Hassenfeld Children's Hospital at NYU Langone
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