American citizens were handed a shock on Thursday when NBC News Chief Foreign Correspondent Richard Engel announced his six-year-old son Henry has died. Henry was suffering from Rett syndrome, which is a genetic brain disorder without any cure.

“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. Mary and Richard,” Engel tweeted.

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As per the National Institute of Neurological Disorders and Stroke, the Rett syndrome can lead to the loss of the usage of hands, issues with walking, slowed brain, seizures and head growth.

Engel also tweeted a link of the memorial page to the Texas Children’s Hospital website in the subsequent tweet and said Henry’s cells are being used by researchers to help cure the syndrome.

“Researchers are making amazing progress using Henry’s cells to help cure RETT Syndrome so others don’t have to endure this terrible disease (sic.),” the tweet read.

Henry was born on September 29, 2015, to Richard and Mary. His parents later noticed a deficiency in his development as an infant, which led to a string of medical examinations and genetic tests. It was at this time when doctors discovered that Henry had a mutation in his MECP2 gene and diagnosed him with Rett syndrome.

“MECP2 mutations cause Rett syndrome, a disorder that typically affects girls after their first birthday, robbing them of learned skills and leaving them with cognitive deficits, loss of speech, and a variety of motor difficulties,” the Texas Children’s Hospital website read.

Richard and Mary brought Henry to Texas Children’s Hospital’s Duncan Neurological Research Institute in 2018, where the Founding Director, Dr. Huda Zoghbi, studied the child closely.

Dr. Zoghbi also gave a tribute to Henry, who was in his career in the last couple of years. “Henry was special in so many ways. His loving and endearing smile, and the way he connected with his eyes, stole my heart from the time I met him,” he said.

The Doctor added that Henry’s fight against the syndrome was ‘incredible’. He also said that Henry has left memories to everyone at the Duncan NRI.

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“We will continue to push as hard as possible to develop treatments. This is how we will honor his life,” the doctor continued.

Richard Engel is known to share updates on his son’s health for a long time and in March of the ongoing year, he revealed that Henry’s health had deteriorated.

“His condition progressed and he’s developed dystonia: uncontrolled shaking/ stiffness. He was in the hospital for 6 weeks, but is now home and getting love from brother Theo,” he wrote at the time.