NBC News' chief foreign correspondent Richard Engel shared the sad news Thursday that his 6-year-old son Henry had passed away. The couple had been open about the child's rare genetic condition.
On Twitter, Engel wrote: "Our beloved son Henry passed away. He had the softest blue eyes, an easy smile and a contagious giggle." He was always surrounded by love, and he returned it as well.
According to a tribute posted on the Texas Children's Hospital website, Henry's parents first noticed he wasn't meeting developmental milestones when he was just an infant.
A genetic test revealed that he had a mutation in the MECP2 gene. It causes cognitive deficits, speech loss, and a variety of motor difficulties in girls after their first birthday.
Since 2018, Henry had been receiving treatment at Texas Children's Hospital's Duncan Neurological Research Institute.
Dr. Huda Zoghbi, a scientist at the institute who studied Henry's mutation, described Henry as "special in so many ways."
On Thursday, Engel tweeted: "Researchers are making amazing progress using Henry's cells to cure RETT Syndrome so that others do not have to suffer this terrible disease."
Henry Engel's family has shared updates on Henry through essays in 2018 and 2019 about both joys and heartbreaks.
Eventually, he developed dystonia, which involves uncontrolled shaking and stiffness," he said. "He was in the hospital for six weeks, but is now home and receiving love from brother Theo."