NBC News chief foreign correspondent Richard Engel announced Thursday that his 6-year-old son, Henry, had died after being diagnosed as an infant with a rare genetic neurological disorder called Rett Syndrome.
"Our beloved son Henry passed away. He had the softest blue eyes, an easy smile and a contagious giggle. We always surrounded him with love and he returned it, and so much more," Richard wrote a tweet announcing his son’s death.
Engel also shared a link to a memorial page on Texas Children's Hospital's website, where Henry was treated, which noted that Henry passed away on Aug. 9, 2022, and included additional details about his medical journey.
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"When he was still an infant, his parents noticed that he was not reaching his developmental milestones, and he underwent numerous medical exams to discover the cause," it read in part.
Engel previously opened up about the heartbreaking moment he learned about his son's diagnosis in a 2018 interview with TODAY.
“I called the doctor and he said, ‘We found something. It’s very, very severe. It’s life long, not treatable,’” Engel said at the time. “It was the worst day of my life."
What is Rett Syndrome?
Rett syndrome is a rare genetic neurological disorder that affects brain development and leads to the loss of motor skills and speech abilities, as well as cognitive deficits. It's caused by the MECP2 gene on the X chromosome not functioning properly due to, in almost all cases, a mutation on the gene. The MECP2 gene dictates production of a protein that's important to brain function and the expression of other genes, according to the National Institutes of Health.
"It's typically not inherited. It is a new change that happens in the baby's DNA right after conception. ... As far as we know, there's not a specific cause for it, and it seems to be random," Dr. Sumit Parikh, a neurologist with the Center of Pediatric Neurosciences at the Cleveland Clinic, told TODAY.
Rett syndrome is estimated to affect one in every 10,000 to 15,000 live female births worldwide, according to the National Institutes of Health. It’s more common in females because they have two X chromosomes; when it occurs in males, it’s more severe because they only have one X chromosome. That's because the non-affected X chromosome in females allows half their cells to have a normal copy of the MECP2 gene, whereas in males, all their cells are affected due to the mutation, Dr. Marc Patterson, a pediatric neurologist at the Mayo Clinic in Rochester, Minnesota, told TODAY.
A diagnosis is confirmed through genetic testing, but doctors may make also clinical diagnosis based on symptoms, the experts said.
What are the symptoms?
Children with Rett Syndrome typically start out growing normally and then experience a slowing of development toward the middle of the first year of life, and after that point, they may take longer to reach or never attain developmental milestones, Patterson said.
“One of the earliest signs in a typical case is the growth of the head slows down, and that (is) classically seen before there’s any change in development,” said Patterson, urging parents to make sure their child's head is measured regularly at checkups.
Children with Rett syndrome can lose motor skills, including purposeful movement of the hands, and may develop scoliosis or difficulties with their gait, which make them very unsteady, Patterson said.
"One of the very characteristic changes is that they develop unusual movements of the hands, which are described as hand wringing, or hand knitting," said Patterson. Patients may also experience dystonia, where muscles contract involuntarily and the limbs or trunk are held stiffly in an unusual position, he added.
"Children who are able to acquire speech tend to lose that ... and there's quite a high frequency of autistic features," Patterson said. "Additionally, a number of children will get an unusual pattern of breathing and other problems, including heart rhythm problems."
Seizures and epilepsy are also common among Rett syndrome patients, Parikh said.
In the 2018 interview, Engel recalled the devastating prognosis for Henry: “It’s not just delay. It means life-long, permanent, untreatable physical and intellectual impairment."
What is the life expectancy with Rett syndrome?
“The lifespan for typical Rett syndrome (in women) now is much better than it used to be, with individuals surviving into their 20s to 50s,” said Parikh, adding that if the problem with the MECP2 gene is more severe, as it often is in males, life expectancy is much lower.
“It’s not uncommon for boys ... to succumb to this illness within the first decade,” said Patterson.
Death may be caused by overall brainstem failure or because the disease progresses to a point where the patient cannot support normal functions, such as swallowing or breathing, Patterson added.
Are there any treatments for Rett syndrome?
“Unfortunately, there isn’t any disease-modifying therapy at the moment that’s approved, but there’s a lot of active research going on,” said Patterson, adding that physical or occupational therapy can help with symptoms, such as loss of motor skills.
One of the first drugs for specifically for Rett syndrome has finished clinical trials and is awaiting review by the Food and Drug Administration, said Parikh. He added that the goal of the drug is to help make symptoms milder and it would not reverse the condition.
Scientists are also looking into gene therapy, trying to find ways to modify the expression of the MECP2 gene or compensate for the abnormal expression, said Patterson.
One of those scientists is Dr. Huda Zoghbi, director of the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, who worked with the Engel family and got to know Henry. On Thursday, Engel shared that her team of researchers at Duncan NRI are using Henry's cells to help cure Rett Syndrome.
In Henry’s case, his mutation was so unique that he was actually the first person to have it, Zoghbi said. “We took cells from Henry and also began to research engineering mice that will model the same mutation that Henry had," she added.
“We’ve learned so much from so many patients with Rett syndrome, but because (Henry’s) mutation was a little different, it allowed us to think slightly differently about other approaches,” said Zoghbi.
"I think Henry really epitomizes how patients inspire so many people," she added.