A team of researchers from two medical centers in Taipei has discovered that a gene, identified as GNB4, can trigger hereditary motor and sensory neuropathies (HMSN) if its DNA chain is incomplete.
The group discovered that the gene had this effect after spending years studying a family whose members suffer from HMSN, a heterogeneous group of various inherited neuromuscular disorders.
Lee Yi-chung (李宜中), an attending physician at the Taipei Veterans General Hospital’s Neurological Institute, on Monday said that a man surnamed Lin (林) was diagnosed at the hospital several years ago with Charcot-Marie-Tooth disease, a type of HMSN.
Lee said that the patient first noticed his leg muscles started to atrophy at the age of 13, and they continued to wither until he was 46 years old and could no longer walk.
Several members of Lin’s family also suffered symptoms of muscular disorders, including the deformation of their arms and legs, and weakness in their leg muscles, Lee said, adding that many HMSN patients need to use a wheelchair as their disorder progresses.
Prior to going to Taipei Veterans General Hospital, Lin had visited many doctors and specialists around the country after he lost the ability to walk, but they had failed to find the cause of his illness, Lee said.
With the participation of Lin and his family, the research team — composed of members of National Yang Ming University’s Brain Research Center and Taipei Veterans General Hospital’s Neurological Institute — conducted years of research on the family that led them to identify the link between the GNB4 gene and HMSN.
The findings were published in the American Journal of Human Genetics on March 7.
HMSN are inherited, progressive diseases of the nerves that produce weakness and numbness in the legs and arms as the sufferer’s nerve cells deteriorate progressively until they stop being able to send messages to different parts of the body.
The muscles in an HMSN patient’s hands and feet become weak because they no longer receive messages from the nerves and begin to atrophy from disuse, the American Association of Neuromuscular and Electrodiagnostic Medicine says.
According to Lee, HMSN often manifest in childhood or during puberty. One out of every 2,500 people suffer from the disorders.
At least 9,000 people in Taiwan are afflicted with an HMSN, but because few physicians in the country know about the condition, many patients have not been properly diagnosed, Lee said.