IN 2012, a study on the prevalence of retinitis pigmentosa in India was published in the journal Acta Opthalmologica. The study, which was headed by Dr Jost Jonas from Germany and Dr Vinay Nangia, director, Suraj Eye Institute, Nagpur, brought to light some crucial data―the prevalence of RP was about one in 750 in the adult population in India. The study also found that the prevalence was significantly higher in the rural areas of central India―1:372.
Compared with studies that were held in the west, both the numbers were shockingly high. For example, a 1984 study in Maine, the United States, had shown a prevalence of 1:4,756. Another study in 1984, in Birmingham, England, showed it to be 1:4,869.
Nangia tells THE WEEK that the higher prevalence of RP in India―and specifically in rural areas―may be because of more consanguineous marriages. “That is often the case, although we cannot be sure,” he says. The study, which had 4,711 participants, extrapolated that there would be approximately half a million Indians with RP and about 1.4 million Indians carrying the genes for RP. Nangia said the results showed that greater attention needed to be paid to it.
Dr Prakash Kumar Jain, an ophthalmologist with AyuHealth Hospitals, says that the symptoms of RP become apparent at the age of three or four only in severe cases. As the disease progresses, he adds, a simple retinal dilation can confirm it. Since it can be confirmed through a retinal dilation, most people do not go for advanced testing or gene testing.
However, Nangia insists that gene testing is necessary as there must be a system to understand and store the type of RP. He adds that “India is many years behind” in understanding the types of RP. “We need to identify which gene is defective in RP patients,” he says. “It is important because we are anticipating that gene editing and similar technologies [can be used to cure] almost all conditions, even chronic, and, to an extent, hereditary diseases. So, genotyping and phenotyping [would help patients if a cure is found].”
Nangia adds that newer gene editing techniques are specific. “You may get treatment for a particular kind of defective gene, but that may not apply to another patient with another [type of] defective gene,” he says. “So, genotyping of RP patients in India is perhaps one of the most important things that should be done.”
Jain says that while handling RP cases, the doctors can only offer hope. “We never tell parents that their child is going to lose vision,” he says. “We tell them that there is a lot of research going on. And, if they are lucky, there will probably be some cure in the future.”
But, for that to happen, India must first make a data bank of its RP patients.