Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Am J Hum Biol. 2010 Sep-Oct;22(5):716-9. doi: 10.1002/ajhb.21072.
Estimates of allele frequencies for recessive diseases are generally based on the frequency of affected individuals (q(2)). However, these estimates can be strongly biased due to inbreeding in the population.
The purpose of this study was to gain a better understanding of how inbreeding in the Minas Gerais State population affects phenylketonuria (PKU) incidence in the state and to determine the inbreeding coefficient based on microsatellites.
Inbreeding coefficients of samples of 104 controls and 76 patients with PKU were estimated through a microsatellite approach. Besides, the amount and distribution of genetic variation within and among patients with PKU and control samples were characterized.
No genetic differentiation was observed between the samples. However, the Fis value found for samples of patients with PKU (0.042) was almost 15 times higher than that found among controls (0.003). When corrected by the inbreeding coefficient found among the controls, the PKU allele frequency decreased to 0.0057.
The results enables us to infer that at least 35% of the PKU recessive homozygotes from the Minas Gerais population could be due to consanguineous marriages and suggest that microsatellites can be an useful approach to estimate inbreeding coefficients.
隐性疾病等位基因频率的估计通常基于受影响个体的频率（q(2)）。然而，由于人群中的近亲繁殖，这些估计可能会产生很大的偏差。
本研究旨在更好地了解米纳斯吉拉斯州人群中的近亲繁殖如何影响该州苯丙酮尿症（PKU）的发病率，并确定基于微卫星的近交系数。
通过微卫星方法估计了 104 名对照样本和 76 名 PKU 患者样本的近交系数。此外，还对 PKU 患者和对照样本内和样本间的遗传变异量和分布进行了描述。
未观察到样本之间的遗传分化。然而，PKU 患者样本的 Fis 值（0.042）几乎是对照样本的 15 倍（0.003）。当用对照样本中的近交系数校正后，PKU 等位基因频率降至 0.0057。
这些结果表明，米纳斯吉拉斯州至少有 35%的 PKU 隐性纯合子可能是由于近亲结婚造成的，并表明微卫星可以是一种估计近交系数的有用方法。
