Multi-Locus Models to Address Hb F Variability in Portuguese ß-Thalassemia Carriers.

Hb F production is under the influence of major quantitative trait loci (QTL). The present study aims: i) to replicate the association with Hb F for representative genetic variants in the three major Hb F QTLs in a Portuguese sample of ß-thalassemia (ß-thal) carriers; and ii) to test different genetic multi-locus models to account for the genetic component of Hb F variation. A population sample of 79 Portuguese ß-thal carriers (39 males, 40 females), aged between 2 to 70 years old, were genotyped for polymorphisms in the locus control region (LCR)-5' hypersensitive site 4 (5'HS4) rs16912979, XmnI-HBG2 rs7482144, BCL11A rs1427407 and HMIP rs66650371, using standard biomolecular procedures. Univariate linear regression models were used to test for genetic associations with Hb F. The minor alleles of the individual variants BCL11A rs1427407 (T) (0.165), HMIP rs66650371 (3 bp del) (0.247) and XmnI-HBG2 rs7482144 (T) (0.196), were found to be significantly associated with increased levels of Hb F (p = 0.029, p = 0.002 and p = 0.0004, respectively), explaining about 6.0, 12.0 and 15.0% of Hb F variation, respectively. In a multiple linear regression approach, the three loci accounted for about 30.0% of Hb F variance. Two genetic risk scores (GRS), rationalizing the number of minor alleles into a single genetic variable, explained about 30.0 and 32.0% of the Hb F variation. In conclusion, we replicated in ß-thal carriers previously reported associations with Hb F. Multi-locus models combining three representative variants of Hb F influencing QTLs can explain a larger amount of Hb F variability.

Association study of variants in genes FTO, SLC6A4, DRD2, BDNF and GHRL with binge eating disorder (BED) in Portuguese women.

A population based case-control study was conducted in Portuguese women with overweight/obesity to investigate the possible association of variants in genes FTO, SLC6A4, DRD2, BDNF and GHRL with binge eating disorder (BED). The distribution of seven polymorphisms was evaluated in 31 BED patients and 62 controls. No significant associations were found between polymorphisms and BED. Of interest, a markedly lower frequency of the FTO rs9939609 obesity risk A-allele was found in BED patients (0.290) in relation to the control group (0.402). Contrasting with anorexia nervosa and bulimia nervosa, our data suggest that rs9939609 A-allele has no potential role in BED.

Distribution of the - 13910C>T polymorphism in the general population of Portugal and in subjects with gastrointestinal complaints associated with milk consumption.

BACKGROUND: The - 13910C>T polymorphism has been associated with lactase persistence (LP) in European populations. AIM: To assess - 13910C>T genotypes across Portugal and in adult individuals with unspecific gastrointestinal complaints associated with milk consumption. SUBJECTS AND METHODS: This study genotyped - 13910C>T in the general population from Northern (n = 64), Central (n = 70) and Southern (n = 65) Portugal and in 40 subjects with gastrointestinal symptoms. Additionally, the concordance was evaluated between breath-hydrogen test and - 13910C>T genotypes in 65 samples. RESULTS: An overall frequency of 0.349 for the LP - 13910*T allele was estimated in the general population, with a noticeable decrease in the South (0.269) compared with North (0.383) and Centre (0.393). Among the symptomatic group, the frequency of the - 13910*T allele (0.363) was not significantly different from the general population. A 94% concordance was found between the breath-hydrogen and the molecular tests. CONCLUSIONS: This study suggests that (i) the distribution of the LP polymorphism is not uniform across the country, (ii) genotyping - 13910C>T is a good diagnostic tool for lactase status in the Portuguese population and (iii) self-reported gastrointestinal complaints are not good predictors of the LP status, implying that a significant part of those complaints may not be related to hypolactasia.

SLC40A1 Q248H allele frequencies and associated SLC40A1 haplotypes in three West African population samples.

BACKGROUND: Ferroportin is a transmembrane protein responsible for iron export from enterocytes and macrophages. Mutation c.744G → T (Q248H), located in exon 6 of the ferroportin gene SLC40A1, is found as a polymorphism in populations of African origin. This mutation has been extensively analysed in African-Americans, but poorly studied in native African populations. AIM: To increase information about Q248H mutation frequency in native sub-Saharan populations examining three West African populations. SUBJECTS AND METHODS: Samples from S. Tomé e Príncipe (n = 115), Angola (n = 156) and Republic of Guinea (n = 170) were analysed for Q248H mutation and for two polymorphisms, IVS1( - 24)G → C and microsatellite (CGG)(n), using standard molecular methodology. RESULTS: The estimated frequencies of Q248H allele were 2.2% in S. Tomé e Príncipe, 3.5% in Angola and 4.1% in Republic of Guinea. Analysis of polymorphisms IVS1( - 24)G → C and (CGG)(n) showed mutation allele c.744T to be strongly associated with haplotype IVS1( - 24)G/(CGG)(7). CONCLUSIONS: This study confirmed the presence of Q248H mutation at polymorphic frequencies in three native sub-Saharan populations. Analysis of two additional markers in the same gene support a single origin of the mutant allele c.744T in the haplotype background IVS1( - 24)G/(CGG)(7).