Marriage within family may lead to chromosomal disorders, warns doctor

Mangaluru, Mar 21: Consanguineous marriages — sanguine meaning blood or blood relation marriages is a common practice followed across many parts of our country. Most commonly, first cousins — uncle's son marries auntie's daughter or uncle marries his sisters daughter.

Most of us do not even recognize the pros and cons of such marriages but research and studies have proved that cousins who marry among themselves run double the risk of birth defects in their children. Genetic/chromosomally abnormalities are often found which can have long standing consequences.

Dr. Pramodha MS, Consultant- IVF & Reproductive Medicine Manipal Fertility, Mangaluru said, “While assessing the consequence of consanguineous against non-consanguineous (non-blood related) marriages in health and disease, several scientific studies have shown that consanguinity leads to abnormality among infants before, during or immediately after birth, increased incidence of birth defects, genetic diseases including blinding disorders, blood cancer (acute lymphocytic leukemia), breathing problems for children at birth (apnea), increased susceptibility to disease etc.”

Dr. Pramodha said, “Babies born out of such wedlock could have a multiplicity of congenital problems. Heart problems, still births, lung issues, nervous disorders and other genetic abnormality like Down syndrome etc. The problem in such close relative marriages surfaces when one of the partners carries a defect in any of the genes associated with some form of illness. “

Why do consanguineous marriages result in children with genetic diseases?

Dr. Pramodha said, “The vast majority of the problems are caused by recessive genes. Everyone carries some abnormal recessive genes, but most people don’t have a defect because the normal gene overrules the abnormal one. But if the couples have abnormal recessive genes being related to each other as cousins almost 2 in every 4 babies are likely to have chromosomal abnormalities.”

She said, “When you marry within the community with one who may also have such a family defect, the child inherits two copies of this faulty gene, and thus has the defect. But when you marry outside the community, you bring in genes from a much larger gene pool, and the odds that the child will inherit the problem reduce remarkably.“