Consanguinity and genetic disorders. Profile from Jordan.

Area of Science:

• Human Genetics
• Medical Genetics
• Reproductive Health

Background:

• Consanguinity, defined as marriage between relatives, is prevalent in Jordan, with 20-30% of marriages occurring between first cousins.
• There is growing concern regarding the role of consanguinity in the incidence of genetic diseases.

Purpose of the Study:

• To determine the specific categories of genetic disorders associated with consanguineous marriages.
• To investigate the association between first-cousin marriages and various genetic conditions.

Main Methods:

• A study of 623 families with genetic syndromes, congenital anomalies, or mental retardation was conducted.
• Consanguinity rates were analyzed and compared to the general population rates for first-cousin marriages.

Main Results:

• First-cousin marriages were significantly higher in families with autosomal recessive conditions (69%) and sporadic undiagnosed conditions (41.7%) compared to the general population.
• The association was not significant for dominant, X-linked, or chromosomal conditions.

Conclusions:

• Autosomal recessive disorders show a strong association with consanguinity.
• Approximately 30% of undiagnosed sporadic cases of mental retardation and congenital anomalies may stem from autosomal recessive conditions, indicating recurrence risks.