Did you know that the stiffness in your child's leg could be because of an inherited brain disorder?
A four-year-child from Punjab, who was unable to walk and sit without support, has been diagnosed with a mutation in his DARS gene, which causes a disorder called Hypomyelination with Brain Stem and Spinal Cord Involvement and Leg Spasticity (HBSL). The disease, experts said, was so rare that only nine other children across the world are known to be suffering from it.
"It is a rare disease that occurs when people do not have enough myelin, the substance that coats nerve fibres and enables the transmission of electrical impulses in the nervous system," said Dr IC Verma, director, centre for medical genetics, Sir Ganga Ram Hospital, who was part of a 16-member international team that identified the gene mutation.
Dr Verma got curious when scans of the four-year-old's brain were normal. "His brain was fine but he could not walk. We could not detect the cause of the disease so I contacted Dr Nicole Wolf, Professor of Child Neurology, VU University Medical Center, Amsterdam, who had come across similar cases," said Dr Verma.
"A team of 16 researchers from India, the Netherlands, Australia, Canada and the US examined the genomes of all the children who appeared to be suffering from the same disease, and the genomes of their parents using two methods - whole genome sequencing and exome sequencing. The examination later confirmed that they all had mutations in the DARS gene," Dr Verma added.
The findings have been published in the American Journal of Human Genetics this month.