Using the whole exome sequencing technique, researchers have discovered that the genetic cause behind developmental disorders such as autism is mutation in the gene EBF3.
What Are Developmental Disorders?
Developmental disorders are complicated conditions of the nervous system, reflected as intellectual disability and autism spectrum disorders (ASD) in affected individuals. These conditions are visible at a very early age and can be long-lasting, ranging from being moderate to severe. For most of these disorders, treatment options are very limited and no exact diagnosis and cure have been found by far.
Gene EBF3 Identified As The Reason Behind Developmental Disorders
Hsiao-Tuan Chao and his team of researchers performed a study to better understand some of the developmental disorder conditions. Published in the American Journal of Human Genetics, the study involved observing new variants of the gene EBF3 in three different patients displaying symptoms similar to a newly described developmental disorder.
The key traits found in all three patients included coordination problems, delay in development, abnormal social behavior, speech difficulties, recurring motor activities, high pain-bearing intensity and limited facial expressions at an early age.
The exome sequencing technique was used by the researchers to identify all the genes in a person's genome. The study performed on the patients revealed the presence of two new mutations of gene EBF3 that were missing in the parents of the patients. Variation in EBF3 is uncommon in normal population but pretty common in population suffering from intellectual disability and ASD.
Chao, a postdoctoral research fellow of pediatric-neurology at Baylor College of Medicine, explained that gene plays an integral part in the normal neurological development.
"It is one of the key factors involved in how neurons develop and connect with each other, but has not been studied in detail. In animal models, mutations that cause the gene to lose its function result in death of the embryo. EBF3 had never before been associated with a disease," said Chao in a press release.
Experiment On Fruit Flies Confirms EBF3 Mutation Causes Neuro-Developmental Disorders
The researchers doubted that the condition of the three patients suffering from developmental disorders and demonstrating mutation in the same gene could be a coincidence. So they could not base this finding as a concrete proof to infer that gene mutation caused the disorders. To confirm their discovery, the researchers analyzed the outcome of gene variations in the experimental fruit fly.
The experiment involved genetic engineering of fruit flies in bearing the mutations present in the patients. The flies with the defective gene were unable to perform the functions of flies with normal gene. The outcome was very severe resulting in the death of the embryos of the flies, whereas when the human gene without mutation was put, the development of the flies was perfectly normal.