relation marriage

Hello DR, Please advise me. My girl friend is daughter of my mother's own younger brother. Our marriage will get birth defect for our child? please help me... Thanks...

[Jordanna Joaquina, MS, CGC]

Consanguinity refers to when both members of a couple are related to each other by at least one common ancestor. If I understood you correctly and there are no other marriages in the family between other family members, you are your girlfriend are first cousins.

We all have two copies of almost every gene - one from each parent. In autosomal recessive (AR) conditions, it is typically necessary to have two mutations, one in each gene copy, to be affected. People with only a mutation in a single gene are called carriers, and typically do not have any symptoms of the condition.

It is believed that we all are carriers of at least 8-10 different autosomal recessive conditions. The chance that both members of a couple are both carriers of the same AR condition is increased if they are related to one another, as they each could have inherited a mutation from the same common ancestor.

To give some background information, the general population risk for two non-related people to have a child with a birth defect is estimated at 3-4%. In the absence of a known autosomal recessive condition in a family, the risk for first cousins to have a child with a birth defect is believed to be doubled, 6-8%.

We recommend that the couple meet with a genetic counselor, who can more accurately assess risk based on ethnicity, family history and personal history. A genetic counselor can discuss the benefits and limitations of all available genetic testing options.

[vignsh]

Thank you so much doctor.Can you please tell me that genetic counselor in chennai city (INDIA, state-Tamilnadu).I dnt know where i go and approach.Please help me.

[kavi1978]

Dear Dr,
I am from India, wish to know details about relative marriages.
My grandfather had five siblings including my mother ie three females and two males among these my mother and my uncle are next to each other ie youngest.My mother get married my father, who is non-relative but my uncle, get married his own elder sisters daughter (who's husband is non-relative) having two siblings including my girl friend (youngest), so I felt my girl friend is very closely related to me from both side of her parents.Kindly let me know whether is it advicable to get marry her, also the possibilities of birth defect of the child if we get marry each other. Moreover my uncle is a diabetic person.