Possible Effects of Cousin Marriages – 1
Eleven months old Abdul Ghani is today’s warrior. Abdu Ghani is only child of his parents who belong to Sialkot from a lower middle class family. His mother was worried when he had recurrent fever and abdominal swelling since his birth. She reached pediatric hospital in Lahore after many referrals. Abdul Ghani was diagnosed as case of Bilateral Wilms tumor. (I will discuss Wilms tumor in next blog). So far Abdul Ghani has received six pre op chemotherapy cycles and waiting for surgery. Let’s pray and hope his successful surgery and recovery.
Poor child is having this disease since birth, As per family history, Abdul Ghani’s mother is married to her first cousin, Grandparents of both of them were first cousins too. Most of siblings are married to their first, second or even fourth cousins. There are many diseases labeled as genetic disorders but there are many not labeled as genetic disorder but have relation with genetic mutation and disorder and cousin marriage is directly linked with genetic diseases.
Marriage between cousins is taboo in much of the Western world. In
the United States, 31 of 50 states outlaw marriage between first cousins, or
allow it only under certain circumstances.
Although cousin marriage is banned in much of the US, the practice
is tolerated and even encouraged in other parts of the world including Pakistan.
In South Asia and the Middle East, for example, 20-50% of marriages are between
first cousins or even closer relatives. They're in good company. More than 10%
of people worldwide are married to a second cousin or closer, or have parents
who are cousins.
Genetically speaking that means they shared their DNA. And the more closer relative they marry the more DNA they share, the greater the chance their offspring will have a genetic disease like cystic fibrosis, sickle-cell anemia and Thalassemia.
Most important is, Parents don’t have to be sick in order to give child a genetic disease.
For example: Sickle cell anemia is caused by a mutation in the gene, both mother and father must pass the defective/ mutated form of the gene for a child to be affected. So, if child only have one defective copy, kid is unaffected. Instead, he/she is called a “carrier”. If one carrier marries with a non-carrier, there’s no risk of the kids getting sick. But when both parents carry a defective copy of gene, then the kids have a 25% chance of inheriting two copies of the defective gene and having the disease.
Scientists have calculated the numbers and it shows the risk that the cousins would have a kid who inherits a genetic disease is 4-7%. For the general population, it’s 3-4%. But here’s the catch: There may be thousands of defective genes for malignancies and blood disorders that could be hiding in family tree and there are chances that these defective gene express themselves in case of cousin marriage.
Moreover, if kids also marry their first cousins and their kids marry their first cousins it’s a recipe for disaster. Because instead of introducing new, potentially helpful genes into the family gene pool, they are recycling the old and possibly dangerous ones.
As per a study conducted in UAE
population about Consanguinity in Leukemia and Lymphomas by Bener et al. The
consanguinity rate in the families of patients with ALL (Acute Lymphocytic
Leukemia) is significantly higher than those with NHL and HL.
In 'Consanguinity in Context,' medical geneticist Alan H. Bittles of
University of Australia examines and explains common misconceptions about
cousin marriage from legal, cultural, religious and medical perspectives.
Bittles writes, there's no doubt that children whose parents are close
biological relatives are at a greater average risk of inheriting genetic
disorders. But the risks of illness and early death are three to four percent
higher than in the rest of the population.
In native population of Pakistan, the rate of consanguineous marriages is high. Pediatric Cancer prevalence is increasing. Pakistani population and Government need to realize the consequences of cousin marriage and consider legislation as per medical perspective. As a rule, cousin marriage should not be a tradition to avoid genetic mutations and deformities. We shall see Thalassemia and its relation to cousin marriage in next blog.
We all pray for Abdul Ghani’s recovery and ease for his family. Aameen
Note: Names have been changed
to protect identity.
Ref: Business Insiders’s article written by Gene Kim and Shira Polan in 4 Aug 2018
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