Variants in the aromatase gene and on the Y-chromosome are not associated with adult height or insulin resistance in a UK population

Genetic polymorphism of human Y chromosome and risk factors for cardiovascular diseases: a study in WOBASZ cohort

Genetic variants of Y chromosome predispose to hypertension in rodents, whereas in humans the evidence is conflicting. Our purpose was to study the distribution of a panel of Y chromosome markers in a cohort from a cross-sectional population-based study on the prevalence of cardiovascular risk factors in Poland (WOBASZ study). The HindIII, YAP Y chromosome variants, previously shown to influence blood pressure, lipid traits or height, as well as SNPs defining main Y chromosome haplogroups, were typed in 3026, 2783 and 2652 samples, respectively. In addition, 4 subgroups (N∼100 each) representing extremes of LDL concentration or blood pressure (BP) were typed for a panel of 17 STRs. The HindIII and YAP polymorphism were not associated with any of the studied traits. Analysis of the haplogroup distribution showed an association between higher HDL level and hg I-M170 (P = 0.02), higher LDL level and hg F*(xI-M170, J2-M172, K-M9) (P = 0.03) and lower BMI and hg N3-Tat (P = 0.04). Analysis of STRs did not show statistically significant differences. Since all these associations lost statistical significance after Bonferroni correction, we conclude that a major role of Y chromosome genetic variation (defined by HindIII, YAP or main Y chromosome haplogroups) in determining cardiovascular risk in Poles is unlikely.

Y chromosome of the inbred mouse KK/Ta strain is associated with reduced body size in Y-consomic strains

Background

We have established 17 Y chromosome consomic (Y-consomic) mouse strains in an inbred DH/Sgn strain. In this study, based on investigations in four different genetic backgrounds, we proved that the Y chromosome of the inbred mouse KK/Ta strain is associated with reduced body size.

Findings

In the DH-Chr Y-+/+ background, Y chromosome substitution significantly decreased the body weight in DH-Chr Y^KK-+/+ and DH-Chr Y^SJL-+/+ strains, and the DH-Chr Y^KK-+/+ strain was the lightest among the 17 Y-consomic strains. In the DH-Chr Y-Dh/+ background (Dh/+ mice have skeletal malformations and are usually lighter than +/+ mice), although Y chromosome substitution did not significantly alter the body weight, the DH-Chr Y^KK-Dh/+ strain was the lightest among the 17 Y-consomic-Dh/+ strains. In the (B6.Cg-A^y × DH-Chr Y) F₁-+/+ background, Y chromosome substitution significantly decreased the body weight and length in the (B6.Cg-A^y × DH-Chr Y^KK) F₁ hybrids. In the (B6.Cg-A^y × DH-Chr Y) F₁-A^y/+ background (A^y causes obesity and promotes linear growth), Y chromosome substitution significantly decreased body weight and length in the (B6.Cg-A^y × DH-Chr Y^KK) F₁-A^y/+ hybrids.

Conclusion

A body-size-reducing effect of the Y chromosome of the KK/Ta mouse strain was observed irrespective of genetic background. The effect was observed in the presence of Dh and A^y, the autosomal dominant mutations, both of which are known to have substantial effects on body size. These results suggest that there are Y-linked genes that control the body size in mice.

Population-specific risk of type 2 diabetes conferred by HNF4A P2 promoter variants: a lesson for replication studies

OBJECTIVE

Single nucleotide polymorphisms (SNPs) in the P2 promoter region of HNF4A were originally shown to be associated with predisposition for type 2 diabetes in Finnish, Ashkenazi, and, more recently, Scandinavian populations, but they generated conflicting results in additional populations. We aimed to investigate whether data from a large-scale mapping approach would replicate this association in novel Ashkenazi samples and in U.K. populations and whether these data would allow us to refine the association signal.

RESEARCH DESIGN AND METHODS

Using a dense linkage disequilibrium map of 20q, we selected SNPs from a 10-Mb interval centered on HNF4A. In a staged approach, we first typed 4,608 SNPs in case-control populations from four U.K. populations and an Ashkenazi population (n = 2,516). In phase 2, a subset of 763 SNPs was genotyped in 2,513 additional samples from the same populations.

RESULTS

Combined analysis of both phases demonstrated association between HNF4A P2 SNPs (rs1884613 and rs2144908) and type 2 diabetes in the Ashkenazim (n = 991; P < 1.6 x 10(-6)). Importantly, these associations are significant in a subset of Ashkenazi samples (n = 531) not previously tested for association with P2 SNPs (odds ratio [OR] approximately 1.7; P < 0.002), thus providing replication within the Ashkenazim. In the U.K. populations, this association was not significant (n = 4,022; P > 0.5), and the estimate for the OR was much smaller (OR 1.04; [95%CI 0.91-1.19]).

CONCLUSIONS

These data indicate that the risk conferred by HNF4A P2 is significantly different between U.K. and Ashkenazi populations (P < 0.00007), suggesting that the underlying causal variant remains unidentified. Interactions with other genetic or environmental factors may also contribute to this difference in risk between populations.

Polymorphisms in the CYP19 gene that influence bone mineral density

Osteoporosis is a prevalent disease with a strong genetic component. Estrogens play a critical role in bone homeostasis. The aromatization of androgenic precursors is the main source of estrogens in men and postmenopausal women. Thus, aromatase is an attractive osteoporosis candidate gene. In this paper the influence of aromatase activity and aromatase gene variants on skeletal homeostasis is reviewed. The results of studies regarding the association between some common polymorphisms of the aromatase gene and bone mineral density and the risk of osteoporotic fractures are described. The mechanisms involved and the potential usefulness of those genetic data in the prevention and management of osteoporosis are discussed.

Evidence of genetic regulation of fetal longitudinal growth

BACKGROUND

Genetic as well as environmental factors are important determinants of fetal growth but there have been few studies of the influence of paternal factors on fetal growth.

AIM

To study the influence of paternal anthropometry on detailed measurements of offspring at birth.

DESIGN

A prospective cohort study involving biochemistry, and anthropometry, of mothers and fathers at 28 weeks gestation, and detailed anthropometry of children within 24 h of birth.

SUBJECTS

567 White Caucasian singleton, non-diabetic, full term pregnancies recruited from central Exeter, UK.

RESULTS

Paternal height, but not paternal BMI, was correlated with birth weight (r = 0.19) and with birth length (r = 0.33). This was independent of potential confounders and maternal height. All measurements of fetal skeletal growth including crown-rump, knee-heel and head circumference were associated with paternal height. Maternal height showed similar correlations with birth weight (r = 0.18) and birth length (r = 0.26). Maternal BMI was correlated with birth weight (r = 0.27) and birth length (r = 0.15). In a multifactorial analysis 38% of the variance in fetal height could be explained by gestation, sex, paternal height, maternal height, maternal glucose, maternal BMI, parity and maternal smoking.

CONCLUSION

Paternal height has an independent influence on size at birth. This predominantly influences length and skeletal growth of the baby. In contrast to maternal obesity the degree of paternal obesity does not influence birth weight. This work suggests that there is genetic regulation of skeletal growth while the maternal environment predominantly alters the adiposity of the fetus.