Genetic effects of consanguineous marriage

consanguineous marriage population

1. Genetic Effects of Consanguineous Marriage M.SRI ARAVIND LAL B841018

2. INTRODUCTION Consanguineous marriage  is matrimony between individuals who are closely related.   In a clinical sense, marriage between two family members who are second cousins or closer qualifies as consanguineous marriage. This is seen across the  Greater Middle East  region, many other populations have seen a great decline in intra-family marriages. Eight states in USA treat consanguineous marriage as a criminal offence.

3. Population types favouring consanguineous marriages Major populations in Middle East, North Africa, South Asia (20- 50+% of all marriages are consanguineous ) Major populations in Latin America, Japan, China ( 1-10% of all marriages are consanguineous) Recent migrants from Pakistan, India, the Middle East, North Africa and South Asia, becoming permanent residents in Europe , USA and Canada. ( e.g. 1.5 million Turks in Germany, 0.5 million Pakistanis in the U.K .)

4. Consanguinity and genetic disorders No association of consanguinity with autosomal dominant, X-linked and chromosomal disorders (such as Down syndrome) Consanguinity increases the risk of expression of autosomal recessive conditions in the offspring. This effect is more pronounced for rare disorders.

5. Consanguinity and Rare Consanguinity and Rare Recessive Genes Every individual carries on an average 1.4%lethal recessive genes. Prenatal period „ Higher miscarriage rates. Pre-reproductive period „ „Deaths are 4.4% higher amongst 1 st cousin couples than in the unrelated couples.

6. Consanguinity: The Artifact Personal biases „ Lack of population based data „Failure to control for the confounding variables : Lack of education „ Poverty „Others

7. Four generations of an Afghan family

8. Consanguinity: population

9. Congenital anomaly

10. observation Out of 44 offspring from consanguineous parents, 23 individuals (19 males & 4 females) equal to 52.3%, have considerable congenital anomalies or died within first month of birth as result of congenital anomalies . Among 26 individuals (13 M and 13 F) from non-consanguineous parents , no considerable congenital anomaly has been seen. Out of 23 individuals with congenital anomalies, 2 have hearing deficit, 2 show low school performance or very low IQ, 15 died within the first month of birth, 2 have Cerebral Palsy (CP) and 2 have kyphosis

11. Cerebral palsy and krphotic spine

12. References Consanguineous marriages increase risk of congenital anomalies-studies in four generation of an afghan family. Genetic Effects of Consanguineous Marriage: Facts and Artifacts. Consanguineous marriages Trends, impact on reproductive health and research priorities.