Dubai: A Saudi research team from Qassim University has discovered an extremely rare genetic disorder, Bethlem Myopathy, for the first time in the Arab world.
The disorder was identified in a Saudi child, shedding light on the potential genetic implications of consanguineous marriages.
The genetic sequencing was conducted domestically, in line with the national policy of localising genetic testing within Saudi Arabia.
The research
Dr. Haitham Al Dhari, assistant professor and senior specialist in Medical Genetics at Qassim University, said: “Our research team focuses on genetic diseases, particularly rare disorders. The project initially aimed to study Duchenne muscular dystrophy in the Qassim region. This research was conducted in collaboration with Dr. Hamdan Abu Al Bashar, associate professor at the university's medical college, with support from the Deanship of Scientific Research."
The team first identified a group of patients previously diagnosed with Duchenne muscular dystrophy, which led them to connect with a family whose case later became the subject of a published scientific paper. Within the family, one of four children displayed symptoms including muscle weakness, difficulty in movement, and delayed physical activities.
"We visited the family and discovered that the youngest brother was also starting to show symptoms," Dr. Al Dhari said. The team suggested conducting a broader study of the entire family, which helped confirm the genetic nature of the disorder. Following national directives, the team collected samples from the family and decided to conduct the genetic sequencing locally.
Incorrect diagnosis
The findings led to a surprising revelation: the initial diagnosis of Duchenne muscular dystrophy was incorrect. "This is a challenge with genetic muscle disorders — their symptoms often overlap," Dr. Al Dhari noted. "For years, the family lived without knowing the true cause of their child's condition, due to the similarity of symptoms with many other muscular diseases."
Genetic tests revealed a mutation in the COL6A2 gene, which causes Bethlem Myopathy. Of the children examined, two were affected—one of whom carried the disorder, while the other was healthy. The research also revealed a noteworthy aspect regarding the mode of inheritance. "This case involved consanguineous marriage, which suggested an unusual inheritance pattern compared to the few documented cases worldwide," Dr. Al Dhari explained.
Bethlem Myopathy is inherited in either a dominant or recessive manner, meaning a child can be affected with either one or two copies of the defective gene. The newly discovered case in Saudi Arabia was inherited through the recessive pattern—the most prevalent mode of inheritance in the country, often linked to consanguinity.
