Inbreeding and PKU allele frequency: Estimating by microsatellite approaches.
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.


OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Santos
Luciana L
LL
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
da Fonseca
Cleusa G
CG
Vaintraub
Marco T
MT
Vaintraub
Patricia
P
Januário
José N
JN
de Aguiar
Marcos J B
MJ
Raquel Santos Carvalho
Maria
M
D001938:Brazil / Q000453:epidemiology; D003241:Consanguinity; D005787:Gene Frequency; D005808:Genes, Recessive; D005819:Genetic Markers; D005828:Genetics, Population; D006801:Humans; D015994:Incidence; D018895:Microsatellite Repeats / Q000235:genetics*; D010661:Phenylketonurias / Q000453:epidemiology* / Q000235:genetics*; D013223:Statistics as Topic
D005819:Genetic Markers