The condition, scientifically known as strabismus, affects 1 in 20 children and typically the first symptoms will be seen between the ages of 1 and 4. Whilst it had previously been observed to run in families the genetic factors responsible were unknown until now.
The research, carried out by an international team including scientists from Harvard, identified the faulty gene TUBB3. This gene codes for the important cellular component tubulin in nerve cells. This is essential for maintaining nerve axons and ensuring accurate transport.
The study took 15 years and looked specifically at the congenital occurrence of strabismus in a family from Victoria. “We looked at about 50 members of the family (and) about 25 of them were affected in different ways. Some of them had both eyes turning, for others it was one side,” said Dr John Ruddle, a research fellow at the University of Melbourne Centre for Eye Research Australia, and one of the lead scientists in the project.
The family members in the study portrayed particularly strong indications of hereditary strabismus. However, this is not the most common form of the condition. It is hoped that the research will help understanding of non-congenital strabismus progress. There are many theories as to what may cause “simple strabismus” including viral infection and deficiencies in eye sight. “The discovery was important because it has helped build understanding of the development of the nerves that control eye,” said Dr Ruddle.
The current recommended treatments range from wearing an eye patch to corrective surgery. The former highlights the emotional and social distress that the condition can cause for a sufferer, whilst with the later there are risks and complications associated with the surgery.
The research also identified that other problems in the developing brain may have a link to the same defective gene. This includes intellectual and behavioural impairments and facial paralysis, the researchers have term the spectrum of disorders TUBB3 syndromes.