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Inbreeding in a South-American newborn series
Insights
Parental consanguinity was detected in 0.84% of newborns across South America. First cousin marriages were most common, suggesting a preferential mating pattern in urban populations.
Area of Science:
- Human Genetics
- Population Studies
- Reproductive Health
Background:
- Parental consanguinity is a known risk factor for certain genetic disorders.
- Understanding consanguinity rates is crucial for public health initiatives and genetic counseling.
- Previous studies on consanguinity in South America have varied in scope and methodology.
Purpose of the Study:
- To investigate the prevalence of parental consanguinity in a large cohort of non-malformed newborns across seven South American countries.
- To calculate the mean inbreeding coefficient (a) for the studied populations.
- To identify patterns and potential drivers of consanguineous unions in urban South American settings.
Main Methods:
- A cross-sectional study involving 16,137 non-malformed newborn infants.
- Data collection from 64 hospitals across 27 cities in seven South American nations.
- Statistical analysis to determine consanguinity rates and the inbreeding coefficient (a).
Main Results:
- A parental consanguinity rate of 0.84% was detected, with a mean inbreeding coefficient (a) of 0.00053.
- Consanguinity rates were similar (approx. 1%) in Brazil, Chile, Ecuador, Uruguay, and Venezuela, but lower (0.3%) in Argentina.
- First cousin unions constituted 60% of all consanguineous matings, with a higher proportion of female intermediate ancestors.
Conclusions:
- Parental consanguinity is present in South American populations, with notable regional variations.
- First cousin marriages are the predominant form of consanguinity.
- Findings suggest a potential preferential mating pattern favoring consanguinity in urban South American populations, warranting further investigation into contributing factors.
Abstract:
Parental consanguinity was investigated in a series of 16, 137 non-malformed newborn infants, ascertained in 64 hospitals, of 27 cities, in seven South-American countries. Parental consanguinity was detected in 135 (0.84%) newborns, giving a mean inbreeding coefficient (a) of 0.00053. The subsamples for five of the seven countries (Brazil, Chile, Ecuador, Uruguay, Venezuela) showed similar consanguinity rates, of about one per cent, an a ranging from 0.00040 to 0.00070, approximately. One country, Argentina, had a three times lower value for both indicators: consanguinity rate: 0.3%, a: 0.00011. Another country, Peru, could not be individually analyzed because of its small sample size. Considering the whole South-American sample, first cousin represented 60% of all consanguineous matings. Significantly more female than male intermediate ancestors were counted in the specified total of consanguineous matings, suggesting a preferential consanguineous mating pattern for urban South-American populations.