Landmark discovery: Novel gene linked to rare brain disorder

Researchers from the University of Hong Kong’s medical school have identified a novel gene associated with a rare disease impacting brain function.

Mutations in the gene, DDX39B, can lead to developmental delays and hypotonia -- a condition characterized by low muscle tone -- symptoms of a rare neurodevelopmental syndrome, according to university findings.

Led by clinical associate professor Brian Chung Hon-yin from the Department of Paediatrics and Adolescent Medicine, the research team previously estimated that about 1 in 67 individuals in Hong Kong, or 1.5 percent of the local population, are affected by rare diseases.

The financial burden is significant, with each rare disease patient incurring medical costs of around HK$490,000 annually, resulting in a lower quality of life compared to those with other chronic conditions.

“Early genetic diagnosis plays a pivotal role in significantly reducing disease-related costs and the risk of financial hardship,” Chung said.

The study was initiated in 2022 when a local toddler exhibited hypotonia, which hindered feeding and led to developmental delays.

The research team ultimately determined that the mutation in the DDX39B gene is a genetic cause of this rare neurodevelopmental syndrome.

This discovery enabled the identification of six patients with variations in the DDX39B gene across Hong Kong, the United States, the United Kingdom, and Ireland.

“This is a world-first discovery of this novel neurodevelopmental syndrome. These patients have lived with an undiagnosed situation for years, and now we can finally understand the cause of their condition,” Chung said.

“By providing crucial information to the patients and their families, the research helps reduce clinical uncertainties and alleviate parental anxiety, bringing a measure of comfort to those affected and their families.”

(Wallis Wang)