Scientists Identify Three Cataract Causing Genes

Scientists at the Centre for Genetic Disorders, Guru Nanak Dev University (GNDU), in association with researchers from the National Institute of Health, USA and the Institute of Human Genetics in Berlin have identified three genes that lead to cataract among the Indian population.

The joint study by Indian and foreign geneticists claim to have found three new cataract-causing genes, often carried on for many generations in families in the country.

After 30 years of research in the field of ophthalmology, the research team, headed by Prof Jai Rup Singh, ophthalmologist Dr Daljit Singh, and fellow foreign scientists, has identified the three genes those can cause fan-shaped cataract, cerulean cataract and sutural cataract.

While releasing his research work among media persons, Dr Singh informed that this research had been carried out on congenital cataract for the past 30 years during which the Centre collected DNA samples from more than 2,400 persons suffering from genetic diseases of the eye. This DNA analysis on these cases was started in 1990.

Currently, DNA analysis on more than 70 families of congenital cataract is still in progress, Dr. Singh added.

According to Dr. Singh congenital cataract affected about three out of every 10,000 infants and was one of the significant causes of blindness in children and often led to life-long visual disability.

Dr Jai Rup Singh, who is Coordinator at the Centre for Genetic Disorders, achieved the breakthrough by identifying and localizing the genes in Indian families.

Although, the first breakthrough in the field came in 2001 when
two new genes were identified, but in the recent research, scientists discovered that the earlier two genes, along with a newly found third, have been localized to Indian families, Singh said.

The first of these, fan-shaped cataract gene is caused by a single nucleotide alteration which alters the structure of alpha-crystallin-an essential lens protein, eventually leading to congenital cataract that is associated with microcornea.

Another cataract-causing gene that leads to Cerulean Cataract was found during molecular studies by Singh’s team that identified a new type of mutation discovered in a family of three generations. In this, replacement of Lysine-an amino acid, with Arginine was found to final lead to Cerulean cataract, Singh informed.

The third Sutural Cataract develops due to a mutation in a gene that causes high levels of protein to precipitate in the lens, at last causing cataract.

Singh indicated that it is now technically possible to determine, before birth, whether a yet-to-be-born baby would suffer from any of these particular congenital cataracts.