Consanguineous marriage, a marriage between two individuals who are related as cousins or closed relatives .This tradition is quite common, highly practiced and socially favoured especially in North Africa, West Asia and South India.Looking on the positive side,why this marriage is culturally favoured? Sociological studies elicit that consanguinity able in strengthening family relationship and gives higher compatibility between husband and wife,as well as other family members.

However,as the maxim goes,everything in nature is bipolar, or has a positive and negative pole.Genetically,consanguineous marriage highly induced the expression of autosomal recessive diseases and syndromes that will be inherited to the offspring,opposing the social and cultural benefits. The offspring from a marriage will carry identical gene copies from both parents.Thus,if both parents have diseases that can be inherited,for instance,sickle cell anemia ,cystic fibrosis or even thalassemia,there will be higher risk for the newborns to get inherited.Infant mortality and birth defects rates has a double increase compared to non-consanguineous marriage.The closer the biological relationship between parents, the greater is the probability that their offspring will get the recessive genes. Consanguineous marriage also increases the incidence of multifactorial disease such as diabetes,hypertension,cardiac disease for instance artherosclerosis,obesity,and certain types of cancers such as breast cancer, blood cancer and list goes on. These may in turn affect the reproductive outcomes.

How does the disease can be inherited via consanguineous marriage ? And why the risk for the infants to get affected is doubling? Generally,the offspring will get the identical gene from both parents,half is from father and another half is from mother.There are 22 pairs of autosomal chromosomes and 1 pair of sex chromosome(XY for boys and XX for girls).Autosomal recessive diseases usually due to mutations,genetics,or even environment that will affect the sequence and structure of the autosomal chromosome.

Sickle cell anemia as example,it is a genetic disease of red blood cells. Normally, red blood cells are discs like shaped , which gives them the flexibility to travel through even the smallest blood vessels. However, in sickle cell anemia, red blood cells have an abnormal crescent shape resembling a sickle. Sickle red blood cells are sticky,rigid and easily to clump in the blood vessels .This will lead to the blockage of blood supply from reaching the whole body.Lethargy,tired,muscle weakness,and severe pain are the common symptoms that can be shown in patient with sickle cell anemia.How sickle cell anemia is inherited to the offspring? When both father and mother have sicke cell traits( a carrier) , chances of the offspring to have sickle cell anemia is 1 in 4 ,or 25%. there is a higher likelihood of having a child with a recessive condition. According the Clinical Genetics Handbook, children of non-

related couples(non consaguinous marriage)have a 2-3% chance of being born with a birth defect, and children of first cousins(consanguineous marriage) have a 4-6% chance.

Besides having higher risk to be inherited with certain diseases,another reason is consanguinity can reduced HLA (human antigen leukocytes) variants in human population.Marrying someone that is close to us will reduce the variety of HLA.One of the main function of HLA is as immune defensive mechanism.HLA will detects the antigen or bacteria that get invaded in our bodies .The more population of HLA variant that we have,the more our immune cells in our bodies ,the lower the risk for us to have a certain disease. Thus,when there is low population of HLA variants ,as in consanguinuos marriage,the higher the chance for the offspring to get infected.

In Islam, consanguineous marriage is allowed and not prohibited but it is not encouraged.As Allah SWT says in Al quran,Surah An Nisa ,verse 23,

“Also forbidden to you for marriage are your mothers, your daughters, your sisters, your paternal and maternal aunts, your brother’s daughters, your sister’s daughters, your foster-mothers, your foster-sisters, your mothers-in-law, your stepdaughters under your guardianship if you have consummated marriage with their mothers—but if you have not, then you can marry them—nor the wives of your own sons, nor two sisters together at the same time—except what was done previously. Surely Allah is All-Forgiving, Most Merciful”.

And in Surah Al-Ahzab,verse 50 ,

“O Prophet, We have made lawful for you your wives whose bridal dues you have paid,87 and the slave-girls you possess from among the prisoners of war, and the daughters of your paternal uncles and paternal aunts, and the daughters of your maternal uncles and maternal aunts who have migrated with you, and a believing woman who gives herself to the Prophet and whom he wants to take in marriage.88 (O Prophet), this privilege is yours alone to the exclusion of other believers.89 We know well what restrictions We have imposed upon them as regards their wives and those whom their right hands possess, (and have exempted you from those restrictions) that there may be no constraint upon you.90 Allah is Most Forgiving, Most Merciful.”

Allah has stated in Al-Quran ,the prohibited group to marry and the people who are not allowed to be married.In Islam,marrying our own cousin is not go against the syariah law but it is not encouraged to do so as this practice can gives negative impact to the offspring genetically.

In short,consanguineous marriage has been proved to be one of the causes that contributes in increasing the number of inherited diseases in offspring.The couples who has a recessive trait disease and still want to have consanguineous marriage are advised to seek a doctor for screening test and premarital counselling.