The costs of human inbreeding and their implications for variations at the DNA level

@article{Bittles1994TheCO,
  title={The costs of human inbreeding and their implications for variations at the DNA level},
  author={Alan H. Bittles and James V. Neel},
  journal={Nature Genetics},
  year={1994},
  volume={8},
  pages={117-121}
}
An analysis of the world literature on the children of first cousin marriages reveals that the depression of survival in offspring followed from birth (including late miscarriages; at about six months gestation or later) to a median age of 10 years is constant (4.4% ± 4.6) across a wide range of values for population prereproductive mortality. There is thus no evidence for the action of conditional lethals. On the basis of these data, it is calculated that the average human is heterozygous for… 
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294 Citations

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The effects of inbreeding on fertility among inbred adult Hutterites is investigated and significantly reduced fecundity among the most inbred Hutterite women, as evidenced by longer interbirth intervals and longer intervals to a recognized pregnancy, which suggest the presence of recessive alleles that adversely affect fertility among the population.

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A range of primarily social factors, including urbanization, improved female education, and smaller family sizes indicate that the global prevalence of consanguineous unions will decline, which will initially result in decreased homozygosity, accompanied by a reduction in the expression of recessive single-gene disorders.

Effects of Isolation and Inbreeding on Human Quantitative Traits: An Example of Biochemical Markers of Hemostasis and Inflammation

TLDR
This work investigated the effects of individual genome- wide het- erozygosity measured as the multilocus heterozygosity (MLH) on biochem- ical markers of hemostasis and inflammation in 1,041 individuals from the island of Vis, Croatia, where inbreeding is prevalent and a wide range of variation in the genome-wide heterozygosa is expected.

Incest, inbreeding, and their consequences

The comparative role of consanguinity in infant and childhood mortality in Pakistan

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The results indicate that, even after controlling for these non‐genetic variables, inbreeding at the level of first cousin exerted a significant adverse effect on survival in four of the five age intervals examined, neonatal, post‐neonatal, infant and under 5 years.

Effects of genome-wide heterozygosity on a range of biomedically relevant human quantitative traits.

TLDR
Findings suggest that h(R) should be considered as a genetic risk factor in genetic epidemiological studies on common disease traits and are consistent with the well-known effects of heterosis (hybrid vigour) described when outcrossing animals and plants.

Effects of Isolation and Inbreeding on Human Quantitative Traits: An Example of Biochemical Markers of Hemostasis and Inflammation

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Weak associations between PGH and MLH and markers of hemostasis and inflammation suggest that their genetic control may not be highly polygenic and that they could be promising targets for genetic association studies.
...

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