Haplotype and functional analysis of four flavin-containing monooxygenase isoform 2 (FMO2) polymorphisms in Hispanics.
OBJECTIVE
Previous work defined two flavin-containing monooxygenase 2 (FMO2) alleles. The major allele, FMO2*2 (g.23,238C>T), encodes truncated inactive protein (p.X472) whereas the minor allele, FMO2*1, present in African- and Hispanic-American populations, encodes active protein (p.Q472). Recently, four common (27 to 51% incidence) FMO2 single nucleotide polymorphisms (SNPs) were detected in African-Americans (N=50); they encode the following protein variants: p.71Ddup, p.V113fs, p.S195L and p.N413 K. Our objectives were to: (1) determine the incidence of these SNPs in 29 Hispanic individuals previously genotyped as g.23,238C (p.Q472) and 124 previously genotyped as homozygous g.23,238 T (p.X472); (2) determine FMO2 haplotypes in this population; and (3) assess the functional impact of SNPs in expressed proteins.


METHODS
SNPs were detected via allele-specific oligonucleotide amplification coupled with real-time or electrophoretic product detection, or single strand conformation polymorphism.


RESULTS
The g.7,700_7,702dupGAC SNP (p.71Ddup) was absent. The remaining SNPs were present but, except for g.13,732C>T (p.S195L), were less common in the current Hispanic study population versus the previously described African-Americans. Only expressed p.N413 K was as active as p.Q472, as determined by methimazole- and ethylenethiourea-dependent oxidation. Haplotype determination demonstrated that the g.10,951delG (p.V113fs), g.13,732C>T (p.S195L) and g.22,060T>G (p.N413 K) variants segregated with g.23,238C>T (p.X472).


CONCLUSIONS
SNPs would not alter FMO2 activity in individuals possessing at least one FMO2*1 allele. It is likely that these SNPs will segregate similarly in African-American populations. Therefore, estimates that 26% of African-Americans and 2-7% of Hispanic-Americans have at least one FMO2*1 allele should closely reflect the percentages producing active FMO2 protein.
Krueger
Sharon K
SK
Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USA.
Siddens
Lisbeth K
LK
Henderson
Marilyn C
MC
Andreasen
Eric A
EA
Tanguay
Robert L
RL
Pereira
Clifford B
CB
Cabacungan
Erwin T
ET
Hines
Ronald N
RN
Ardlie
Kristin G
KG
Williams
David E
DE
D000483:Alleles; D013956:Antithyroid Agents / Q000494:pharmacology; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D005031:Ethylenethiourea / Q000494:pharmacology; D005822:Genetic Vectors; D005838:Genotype; D006239:Haplotypes; D006630:Hispanic or Latino; D006720:Homozygote; D006801:Humans; D008713:Methimazole / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010105:Oxygenases / Q000235:genetics*; D010597:Pharmacogenetics; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D018807:Polymorphism, Single-Stranded Conformational; D013696:Temperature
D013956:Antithyroid Agents; D017931:DNA Primers; D018076:DNA, Complementary; D005031:Ethylenethiourea; D008713:Methimazole; D010105:Oxygenases; C020066:dimethylaniline monooxygenase (N-oxide forming)