This document discusses the genetic effects of consanguineous (close familial) marriage. It notes that consanguineous marriages are common in parts of the Middle East, North Africa, South Asia, and among recent immigrants from those regions. Such marriages can increase the risk of expressing autosomal recessive genetic disorders in offspring. The document presents an observation of a four-generation Afghan family, finding that over 50% of offspring from consanguineous parents had significant birth defects or died in the first month of life, while no such issues were observed among offspring of non-consanguineous parents.

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.

4. 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.)

5. 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.

6. 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 1st cousin
couples than in the unrelated couples.

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

8. Four generations of an Afghan family

9. Consanguinity: population

10. Congenital anomaly

11. 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

12. Cerebral palsy and krphotic spine

13. 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.