First-cousin marriages up risk of passing genetic disorders

Consanguineous marriages or marriages between first cousins have a higher risk of passing genetic disorders to their offspring, revealed a study by Igenomix on Wednesday.

According to the reproductive genetic laboratory giant Igenomix, in such cases, if both the parents are carriers of the same mutation (disorder), the chances that the child will be affected from a disorder are as high as 25 per cent. The affected child may not lead a normal healthy life.

"Babies born to consanguineous couples have a higher risk of passing genetic disorders to their offspring. In a research, 17 per cent of the couples in case of consanguineous marriages have been found with a high risk of transmitting genetic disorders to their child," Rajni Khajuria of Igenomix said in a statement.

"Consanguineous marriage increases the incidence of many genetic disorders like Retinitis Pigmentosa, Leber Congenital Amaurosis, Stargardt disease and Usher syndrome," she added.

According to World Health Organization (WHO), at least 10 infants in every 1,000 live births suffer from some or the other genetic disorders. Most of these disorders are fatal and can also cause disability for a lifetime. What is worse is that many remain unaware to these disorders till the time they have an affected child.

"Genetic disorders pass on from generation to generation. One could be a carrier of a genetic disorder and still lead a healthy life. Doctors say that they often come across people who are Thalassemia minor patients and they only get to know while being treated for some other problem later in their lives," Khajuria added.

According to Igenomix researchers, they have noticed a peculiar distribution pattern of genetic diseases in families where marriage between close relatives is a common scenario.

"These disorders cannot be cured but can surely be prevented, by running a simple blood test before planning a child. IGENOMIX's Carrier Genetic Test (CGT), helps to determine if both the parents are carrier," said Khajuria.

She added that if both turn out to be a carrier, then the next step for them is PGD (Preimplantation Genetic Diagnosis), which is carried out to select those embryos that are healthy.