Are consanguineous marriages responsible for diseases?
In a complex tale of interrelationships, Malika’s marriage to her first cousin Latif was settled before she was born. When the parents formalised the agreement the groom to be was too young to enunciate his first word. There is nothing unusual about this. Malika’s brother was betrothed to Latif’s sister when they were both toddlers and her mother Saniya was betrothed to her cousin Arif when she, Saniya was seven and Arif one year old. Although Arif was so much younger it had to be him because there was no other suitable boy within the family.
When Arif died a year later Saniya was labelled as cursed. Luckily for her, the parents of a cousin on the other side were willing to have Saniya for a daughter in law and these two were married when both were eighteen. Another marriage within the safe confines of The Family, never mind that several persons in that family were diagnosed with diabetes and repeated intermarriages appeared to be reinforcing the responsible gene.
Malika’s son too was diagnosed with diabetes at the age of three. He died at the age of five due to complications associated with the disease. The entire family mourned for a month. At the end of that period Malika’s younger sister was married to another of their cousins related to her by way of both parents. When asked (in some exasperation) why they did not marry outside the family Malika replied: ‘Because this is how we always do it.’ And that response suffices. Malika’s family is one of countless others who only ever marry their cousins if they can help it.
So the question is: Are cousin or consanguineous marriages responsible for diseases that are genetically transmitted?
Consanguineous marriage, in which two related persons such as first or second cousins marry each other, is very common among several cultures, including the cultures of Pakistan, India, Bangladesh, and some middle-eastern and African countries. People belonging to these cultures together constitute perhaps a fifth of the world’s population. In a consanguineous marriage, chances of both parents carrying the same recessive gene and therefore of their children inheriting the disease carried by that gene are greatly increased. The closer the relationship between the parents the greater the chance of both parents carrying the same recessive gene. Sickle cell disease for example, a condition that causes damage to muscles and organs occurs if an individual inherits two copies of the sickle cell allele, one from each parent. Persons with just one copy of the allele do not get this disease.
In England, research was conducted among a number of Pakistan families when it was found that a high number of children with hearing disabilities came from families where the parents were related to each other in complex ways. “They have about twice the risk of having a child with problems which may be due to a recessive gene if they marry within the family,” said Professor Bob Mueller of the hospital involved in this research.
Genetics however cannot be solely blamed. With diabetes for example, genes and ethnicity are risk factors, but they alone do not determine who gets the disease or its severity. Environment plays a role, as does lifestyle. Staying active, maintaining a healthy weight and eating a balanced diet can help postpone or prevent type 2 diabetes.
So why do people intermarry despite these findings? Why for example in the example cited above is intermarriage almost the only kind of marriage in Malika’s family?
It is probably a case of better the devil you know than the devil you don’t. Marriage within the family allows persons to stay within their comfort zone amongst people they know, often, for women, within close proximity to the family left behind. It means a pre-existing affection amongst in-laws, and closer relationships overall. There is also the not unimportant question of keeping property/finances within the family when marrying within it. In many families however, intermarriage is a question of lack of information and understanding of the risks involving genetic disease. Malika’s son may have survived, who knows, if his parents had taken him to a hospital … always presuming there was a hospital within reach, rather than to a pir who prescribed holy water and a talisman around the child’s neck.
Amongst immigrants from such cultures, consanguineous marriage is often viewed as a means of survival. In an alien environment surrounded by conflicting views and values, marriage within the family is seen as the best way of preserving and perpetuating an identity in imminent danger of being overwhelmed by the adoptive environment.
In the west consanguineous marriage is now considered almost synonymous with incest and marrying a blood relative is banned in some countries, but this was not always so. History and literature are replete with examples of marriages among cousins. If one must cite the example of a towering intellect, Einstein himself was married to a first cousin. None of which makes it right. One can almost see some quarters bristling at that last sentence, since several religious figures, even Fatima, the daughter of the Prophet Muhammad (PBUH) were married within the family. But there was no genetic science in those days, and there is now, and religion advises us to think. Also, let’s not forget that the risk of disease increases with several other factors too. Older women have risky pregnancies. Consuming alcohol during pregnancy is dangerous.
A US National Institute of Health resource says that there is significant literature on infant mortality, congenital anomalies, disabilities and many clinical conditions, often drawing attention to ethnic variations and an increased disease prevalence among Pakistani children in the UK. The situation at home has to be much worse. Something must be done to mitigate the damage.
A tradition of consanguineous marriage points towards an insecure, insular state of mind. Literacy, better education and public awareness campaigns can help broaden horizons. Carrier detection and genetic counselling programs have been successful in reducing the prevalence of inherited disorders in Iran. Community programmes for premarital screening are also useful. According to the Journal of Community Genetics, results from a screening program for sickle cell disease and β-thalassemia indicated that about 90% of couples in Saudi Arabia at risk of having affected children decided to marry regardless because they feared social stigmatisation and/or because wedding plans could not be cancelled at that stage. Therefore premarital screening should take place well in advance of marriage, perhaps in schools. Perhaps also the next generation, a healthier one, will learn to say, ‘This is how we always did it, but not any more.’