Human inbreeding: examples

In a genetics class I attended recently, Professor Scott Weitze recommended a few books including The Family That Could Not Sleep by D.T. Max and Mutants: On genetic Variety and the Human Body by Armand Marie Leroi. I thought I should mention both these books because both deal with mutations that probably arose due to human inbreeding.

The Family… lists many prion related symptoms which seem interesting from the perspective of inbreeding. The Italian family referred to in the title is haunted by progressive insomnia that kills the victims within months due to sleep deprivation. Although this condition is due to prions, the fact that this condition is inherited makes me believe that some inbreeding may be involved. A mutation that promotes the incorrect folding of the protein which creates the prions may have arisen in an ancestor in the family. Due to consanguineous marriages the incidence of the mutation may have increased to the current status within the family. Mutants, too, is a wonderful book that links myth, reported cases, and medical cases of human deformities that have lingered since ancient ages.

While The Family…. consists of many prion related diseases, Mutants starts with the description of the mythical Monster of Ravenna that remarkably resembles patients with Roberts’s Syndrome. Then leading the readers from the battle of preformationists and epigeneticists the book delves into the modern day developmental biology to explain various irregularities during the development of an embryo that leads to deformities. While some developmental irregularities could be due to the environment and chemical agents, others such as ectrodacytly (previously also known as Cleppie Bells or lobster claws) could be due to inbreeding because they seem to be in the individuals that seem to have shared ancestors. Cleppie Bells in a few Scots family, Lobster claws in a British family, Ostrich foot in an African family, and the aleijadinhos of Brazil are some of the examples of ectrodacytly listed by the author. All these deformities are in very small populations sharing a common ancestor. I thought this would probably be interesting especially to those who refute the negative implications of consanguineous marriage.

I would not want to summarize the books because the authors have spent a lot of time and effort to write them. I would suggest though that readers interested in deciphering more about the implications of human inbreeding read both of these books.