Marrying within the family might be great for a whole lot of reasons - lower risk of friction with the in-laws, familial support and a higher fertility rate. But you also run the risk of passing on a whole lot of genetic disorders to your kids, especially of the auditory kind. “Consanguinity is a terrible thing. We found that six out of every thousand births in Tamil Nadu had severe to profound deafness, “ says Dr Mohan Kameswaran, Chief Surgeon of the Madras ENT Research Foundation (MERF), as he went into the results of a decade long study conducted by his centre.
The study was conducted from 2003-12 and 50,000 children were screened as part of it from the “length and breadth of Tamil Nadu”, by the department of community otolaryngology at MERF. The findings were as stark as they were revealing. With 6/1000 kids being found to be deaf (the kind where they need cochlear implants to hear anything), this is almost three times the national average (2/1000 live births) and six times the international average (1/1000 live births).
“What was really shocking for us was that 66 percent of the children who were deaf were born of marriages between close relatives (consanguineous marriages),” adds Dr Kameswaran. Though marriages between cousins, uncle-niece and any other familial combination is supposedly on the decline in urban settings, it remains fairly constant in the rural parts of the state. On the contrary, the study indicated that the rural-urban divide as far as pediatric deafness was concerned was 55-45 percent.
From a scientific viewpoint, the detrimental health effects associated with consanguinity are caused by the expression of rare, recessive genes inherited from a common ancestor.
While these genetic defects have been known to cause retinal, auditory and cardiac disorders in the offspring, at times they can also cause infant mortality. “We need to take steps to ensure that the genetic health of our state is not endangered in any way,” he adds.