The research, by the University of Adelaide in South Australia, also found the defected gene causes intellectual disability only in males – while females are carriers of the gene but are not affected by the symptoms.
Dr Raman Sharma, from the University’s Robinson Research Institute, identified the gene – THOC2 – which causes intellectual disability in about one in 50 individuals.
“We also discovered that it is partial loss of function of the THOC2 gene that leads to the altered brain function and specific facial characteristics associated with this intellectual disability,” he says.
In addition to intellectual disability, the mutated gene can also result in speech delay, elevated body mass index, short stature and seizure disorders.
THOC2 is one of a very few critical proteins present in the human body which are involved in transporting mRNA’s from the nucleus to the cytoplasm within a cell.
“Because there so few identified mutations in genes which carry out this fundamental and essential task, it is really one of the key findings of the research,’’ Dr Sharma said.
“Our findings can immediately help people by providing genetic guidance.
“At least half the people with an intellectual disability across the world do not have a formal diagnosis because the defective gene has not be identified,” Dr Sharma says.
“Advanced genetic technologies have accelerated the discovery of genes responsible for diseases like epilepsy, autism, intellectual disability and other neurological disorders. Eventually these technologies will help identify and put a name to these disorders.
“But the number of genetic conditions in which we have functional understanding of the mutated genes can be counted on two hands.”
Dr Shamra says the next stage is to gain deeper understanding of the THOC2 function and how the defects in this gene lead to clinical outcomes so people with this condition can be helped.
“We can’t treat the condition unless we understand how the defective genes cause the clinical symptoms,” he says.
The Robinson Research Institute lab is one of the few in the world looking at the molecular and cellular pathways altered by the gene variants, according to Dr Sharma.
“Our research is an upcoming field of genetics, which we hope will lead to the discovery of treatments for debilitating intellectual disabilities,” he says.
The research was published this month in the American Journal of Human Genetics.Jump to next article