Why do cousins have retarded children

Objective: This study shows a few common patterns of the consanguineous relationship in the parents of children with ID in India. Materials and Methods: This is a case series research design. Results: Multiple patterns of consanguineous marriages in tribal and nontribal populations were observed.

Conclusion: ID may inherit in individuals from their relatives of the first, second, and third generations who have ID, epilepsy, or mental illness and married in the relationship.

Open in a separate window. Figure 1. Figure 6. Figure 2. Figure 3. History of intellectual disability, epilepsy, and mental illness. Figure 4. History of intellectual disability in third and fourth generations.

Figure 5. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest. Acknowledgment We wish to sincerely thank Asha gram Trust, India, for allowing us to do this study. Range of genetic mutations associated with severe non-syndromic sporadic intellectual disability: An exome sequencing study. The genetic basis of non-syndromic intellectual disability: A review.

J Neurodev Disord. Ropers HH. Genetics of intellectual disability. Curr Opin Genet Dev. Genetics and pathophysiology of mental retardation. Eur J Hum Genet. Review of recent epidemiological studies of mental retardation: Prevalence, associated disorders, and etiology. Am J Ment Retard. Consanguinity and early mortality in the Muslim populations of India and Pakistan.

Am J Hum Biol. Basu SK. Effect of consanguinity among North India Muslims. J Popul Res. The genetic variability and commonality of neurodevelopmental disease. Diagnostic exome sequencing in persons with severe intellectual disability. N Engl J Med. Deep sequencing reveals 50 novel genes for recessive cognitive disorders. Bittles AH. The impact of consanguinity on the Indian population. Indian J Hum Genet. The clinical profile of mentally retarded children in India and prevalence of depression in mothers of the mentally retarded.

Indian J Psychiatry. An epidemiological and aetiological study of children with intellectual disability in Taiwan. J Intellect Disabil Res. Consanguinity and its relevance to clinical genetics. Egypt J Med Hum Genet. Verma IC, Bijarnia S. The burden of genetic disorders in India and a framework for community control. Public Health Genomics. Rajangam S, Devi R. Everyone has a different set of hidden disease genes so that the odds are against people each giving one of the same bad genes to their kids.

Now, the more closely related two people are, the more likely it is that they'll share the same set of hidden disease genes. People might have thought that first cousins were too closely related and so there would be a big increase in genetic diseases if cousins marry. The data doesn't really show this. And if we think about it, it probably isn't surprising that the risk is small for first cousins.

There are lots of places in the Middle East, Africa and Asia where marriages between first cousins are encouraged. There is no rampant genetic disease in these places suggesting all along that the risk was low. You may want to talk with a genetic counselor about the increased risks. They can help you decide whether the small increased risk is acceptable to you. You can find a genetic counselor near you at the link below. More Information Little risk if cousins have kids free registration required The basics on genes and genetic disorders Where to find a genetic counselor.

Search Ask a Geneticist. Little risk for kids of first cousins. Volver a la lista de Preguntas. The legislatures in most states in the United States have passed laws which prohibit marriage between first cousins 1. Consanguinity is rare in the United States; less than 1 in 1, couples are first cousins.

Yet, each year several couples who are first cousins come to our Genetics Clinic for information about their risks of having abnormal or handicapped children. These consultations have prompted us to review the data available for defining the magnitude of the risk faced by these couples. While several studies have been conducted on the effects of inbreeding 2 , it is difficult to translate this data to information useful to these couples.

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