Kathmandu, October 4

Consanguineous marriage has emerged as a leading cause of eye cancer among children. It has been found that a majority of children diagnosed with the disease are born out of consanguineous marriages.

Two-year-old Fatima Khatun of Bara recently underwent surgery for eye cancer in Tilganaga Institute of Ophthalmology.  She was diagnosed with retinoblastoma. It was later found that her parents are blood relatives.

“Nearly 10 children born out of consanguinity marriages are diagnosed with eye cancer every month. Most of these infants are from Bara, Siraha, Sarlahi, Butwal and Bhairahawa,” said Dr Ben Limbu, oculoplasty surgeon at Tilganga Institute of Ophthalmology.

Children diagnosed with retinoblastoma, a rare cancer of the eye, tend to develop and die of second primary cancers in childhood.

The risk of birth defects in the offspring of first cousin marriages has been estimated at five to eight per cent as compared to two to three per cent in non-consanguineous marriages.

“Gene mutations that increase the risk of retinoblastoma and other cancers can be passed from parents to children. Hereditary cancer is passed from parents to children in a DNA, which means only one parent needs a single copy of the mutated gene to pass the increased risk of retinoblastoma on to the children. If one parent carries a mutated gene, each child has fifty per cent chance of inheriting that gene,” Dr Ben said, adding the there is greater prevalence of the disease among communities that practice consanguineous marriage.

Not only this, marriages among blood relatives can lead to severe visual impairment or blindness. “The important symptoms or signs are poor vision, non-development of eye contact with others, night blindness, intolerance to light, enlarged eyeballs, crossed eyes or shaking eyeballs. These can directly or indirectly delay developmental milestones in a child’s life,” Dr Ben said.