2 days ago Nancy Watanabe added an answer: Since consanguineous unions are resulting in hundreds of thousands of children suffering at birth from hemophilia, cleft palate, club-foot, neurological disorders, and other congenital abnormalities, blood-related couples who are infertile show a healthy "defense mechanism," i.e., some physiological barrier that prevents them from becoming the parents of a child afflicted with a physical disability, psychological handicap or premature death before age twenty. While parents may lavish loving care and affection, and may even be able to afford surgical operations to mitigate obvious impairments, the offspring of consanguineous marriages rarely will be able to live a normal life.Famous people who married first- or second-degree cousins and remained childless all of their lives include the nineteenth-century American poet Edgar Allan Poe. His famous short story "The Fall of the House of Usher" suggests the unhappy lives and demise of a brother and sister living together as man and wife. Other portrayals of consanguinity in imaginative literature written by Franz Kafka, William Butler Yeats, John Steinbeck, and in movies like I REMEMBER MAMA are discussed in the "Ultrasound" section in a library reference book:Nancy Ann Watanabe, Beloved Image: The Drama of W.B. Yeats - 1865-1939 (Lanham, Maryland: University Press of America, Rowman & Littlefield). Nancy Watanabe

• 2.34
• University of Washington Seattle

Answer

Reply from Matthias Schaefer:

The answer to your main question is: deleterious genetic mutations are more likely not to be recessive anymore. I am not sure about the notion that public education is to blame for the occurrence of consanguineous unions. For instance, first-cousin marriages had/have a cultural and communal component in some societies in various parts of the world. And belonging to a tribe, group or family line are still important attributes of distinction in some societies. As for your statement: "The problem runs rampant in densely populated nations, while remaining virtually nonexistent in low density or sparsely populated areas of the world." could you, please, provide some references to support this statement?

1 day ago Nancy added a reply to Matthias R. Schaefer: Many thanks for the answer to my main question; I wondered but did not know.Historically, native Amerindians were forbidden to marry outside of their tribal communities; for example, a tribe member whose totem was the raven was not permitted to wed a tribal follower of the whale. As you may know, a sufficiently large gene pool was a sine qua non of avoiding consanguinity. Some native Amerindian tribes are extinct because gene pools gradually diminished. A native Amerindian at the University of Oklahoma, Norman, imparted this info to me.My statement (and my RG question) is derived from a mail outreach campaign from a group I do not know which sent me a big world map color coded to display "Number of surgeries performed": 0 to 100, 100 to 500, 500 to 1000, 1000 to 10,000, 10,000 to 100,000, 100,000 to 400,000, and 400,000+ and to show "Where We Work." Perhaps you are already familiar with this type of data.The address on the broadcast letter is: Susannah Schaefer, CEO; Smile Train. Years of Smiles, P.O. Box 96208, Washington, DC 20090-6208 smiletrain.org I worked several summers as a summer fill-in executive secretary for a medical genetics department at the University of Washington, where I was a scholarship student in the Honors Program. I spent most of my time typing rough drafts, revisions, and final manuscript submissions to academic journals written by a faculty / physician professor who became Dean of the Medical School. Another of my duties was to interface between the Lab Technician / Family Counselor and couples who made appointments for blood work because of genetically transmitted diseases in the wife's or husband's familial pedigree / tree. Also, I have published on imaginative literature and medical genetics.*I thank you most kindly for your inquiry. Sincerely,Nancy*Watanabe, Nancy Ann. "Ultrasound," pages 267 to 326 in BELOVED IMAGE: THE DRAMA OF W.B. YEATS - 1865-1939, Lanham, Maryland, University Press of America / Rowman and Littlefield > > > > Amazon.com/Books [chapers on Yeats's THE POT OF BROTH, THE CAT AND THE MOON, SOPHOCLES'S OEDIPUS AT COLONUS, and PURGATORY; George Stevens's movie I REMEMBER MAMA, Franz Kafka's THE METAMORPHOSIS, John Steinbeck's OF MICE AND MEN, and Juan Rulfo's PEDRO PARAMO: A NOVEL OF MEXICO]. Nancy Watanabe

• 2.34
• University of Washington Seattle

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Nancy Watanabe added a reply Matthias R. Schaefer Thank you very much for pointing out to me the following: "For instance, first-cousin marriages had/have a cultural and communal component in some societies in various parts of the world." Today, I read replies from knowledgeable discussants in a similarly conceived Question asked by an individual living in Lebanon. Before this, I did not know that Muslims follow familial intermarriage as a traditional practice. I am quite surprised since they disapprove of drinking alcoholic and other intoxicating beverages, which also cause birth defects and Alzheimer's. This concerns me because the majority of my contacts on Research Gate are in countries in the geographical region most associated with high Muslim populations. This is the first time I veered into a medical topic. If I had known, I imagine that I would have refrained from posting this question. The other similarly worded question got a lot of responses, mainly from individuals who work in medical fields and respond accordingly. My input as a "generalist" is apt on that site. But I am afraid that I committed a faux-pas. Thanks to you, Matthias, I am now aware of why I received so few responses. With gratitude, Nancy P,S. I placed your responses (above) on the discussion in my account under the name "Nancy Ann Watanabe" because I am merging my personal and authorial accounts. Thank you for adding your reply. View more questions and discussions

I dont think your statement is right. Inbreeding doesn't have that strong effect on human health. The observed frequency of that diseased on humans can not be attributable to inbreeding, the frequency of genes and deleterious mutations arising each generations are more likely responsable of that disease.

Agreed, the genetic consequences of consanguinity are not conventionally discussed, probably because marital union like any socio-cultural-religious concept is sensitive to criticism and questioning - history has shown that religious authorities have have most often condemned scientific advancement when their principles were contradicted. As recently as a decade ago a pope discouraged condom use as a preventive measure against STIs, and condoms are still considered "immoral". A dentist died after being denied a medically indicated termination of pregnancy in the developed world because of the religious views of

"the country" in 2012. The frequency of genetic diseases among certain populations is for the same reasons - their religions or cultures mandate that they are only to marry within their own communities and in doing so the genetic consequence (most commonly of two defective recessive genes or pathogenic compound heterogenecity) are manifested.

However, I disagree with the point on population density. The genetic heterozygosity is far more in the highly populated parts the world - which accounts for why they are a significantly less significant problem in Asia nations, for example; and why sequestered populations such as Ashkenazi Jews are more commonly affected by genetic disease as they practice endogamy.

I think if there are any type of genetic disease in the family then consanguinous marriages should be avoided. Need counseling of the couples. Otherwise no harm.

@Anbreen - Ma‘am, even if there are no overt diseases, the risks of bringing together recessive genes are significant and there would be a genetic stagnation - this would have long term adverse effects on not just the particular incestous line but the surrounding community as well - non-coding intron sequences themselves can be seat of disease. The lack of genetic diversity could prove catostrophic - so is not best to discourage inbreeding as a principle and not wait for the consequences of an unfavourable genetic pile-up? Is it a responsible decision to accept it as practice and ignore the potential consequences?

Very true.... but what is the guarantee that nonconsanguinous couple don't have Recessive/dominant genes. So there is always risk. In order to prevent from such genetic disorders there should be proper screening of the couple in the hospitals especially who are susceptible.

Unfortunately in developing country there is no such screening because of its high cost and unawareness.

Absolutely, Ma’am, non-consanguinous conception too can be affected by genetic disease, but at a much lower frequency. Obviously no one can (or should) dictate terms of procreation - that would become eugenics afterall. but for sake of discussion pertaining to the question, the role of consanguinity in the burden of genetic disease cannot be denied, and theoretically at least, the curtailing the cause would result in a decline in effect..