No association of obesity gene FTO with body composition at the age of 6 months. The Generation R Study

Does the rs9939609 FTO gene polymorphism affect fat percentage? A meta-analysis

This meta-analysis aimed to investigate the association of the rs9939609 FTO gene polymorphism and body fat percentage (BF%). To the best of our knowledge, this study is the first meta-analysis to evaluate the relationship between FTO rs9939609 polymorphism and BF%. We searched PubMed, Web of science, Scopus and Embase to identify studies investigating the relations between the rs9939609 FTO gene polymorphism and BF%. Studies that meet inclusion criteria were collected for the final analysis. There was significant differences in the level of BF% between different genotypes of FTO rs9939609 polymorphism, and the carriers of the A allele of FTO rs9939609 polymorphism had higher BF%. The association was significant between carriers of TT genotype compared to carriers of AA (p = .007) and AT genotypes (p = .04), but not between AT and AA genotypes. This study identified that the carriers of the A allele of FTO rs9939609 polymorphism have higher BF%.

DNA methylation in infants with low and high body fatness

BACKGROUND

Birth weight is determined by the interplay between infant genetics and the intrauterine environment and is associated with several health outcomes in later life. Many studies have reported an association between birth weight and DNA methylation in infants and suggest that altered epigenetics may underlie birthweight-associated health outcomes. However, birth weight is a relatively nonspecific measure of fetal growth and consists of fat mass and fat-free mass which may have different effects on health outcomes which motivates studies of infant body composition and DNA methylation. Here, we combined genome-wide DNA methylation profiling of buccal cells from 47 full-term one-week old infants with accurate measurements of infant fat mass and fat-free mass using air-displacement plethysmography.

RESULTS

No significant association was found between DNA methylation in infant buccal cells and infant body composition. Moreover, no association between infant DNA methylation and parental body composition or indicators of maternal glucose metabolism were found.

CONCLUSIONS

Despite accurate measures of body composition, we did not identify any associations between infant body fatness and DNA methylation. These results are consistent with recent studies that generally have identified only weak associations between DNA methylation and birthweight. Although our results should be confirmed by additional larger studies, our findings may suggest that differences in DNA methylation between individuals with low and high body fatness may be established later in childhood.

Ovarian 25OH-vitamin D production in young women affected by polycystic ovary syndrome

INTRODUCTION

Vitamin D is involved in the regulatory mechanisms of ovarian function and is frequently low in PCOS patients. Since obesity and hyperinsulinemic state negatively influenced vitamin D levels, therefore, we evaluated the production of vitamin D at the ovarian level only in lean and normoinsulinemic PCOS subjects. Basal, GnRH analogue-induced ovarian production of 25OH-vitamin D (VitD) and a direct sampling at ovarian vein level were investigated.

METHODS

Basal and GnRH analogue-induced hormone levels were evaluated at peripheral level in 45 subjects, aged 18-39 years, and in 22 healthy women with age- and BMI-matched as controls. In 12 PCOS patients, undergoing laparoscopy, a venous sampling at both peripheral and ovarian level was further done. All subjects presented low VitD levels, appropriate to the season and with no difference between PCOS and control subjects.

RESULTS

GnRH analogue significantly stimulated plasma LH, FSH, 17-OHP and estradiol secretion (p from < 0.05 to < 0.001 vs basal levels), whereas no effect was observed on both serum AMH and VitD concentrations in all groups. A significant difference (p < 0.006), between peripheral and ovarian veins, was observed in both AMH and estradiol levels in PCOS subjects, while no gradient of VitD was detected.

CONCLUSIONS

All patients presented with low VitD levels. The absence of any VitD variation, both at basal and after GnRH analogue administration, or at peripheral-ovarian vein gradient, suggests no pituitary-ovarian axis involvement in VitD production or its direct ovarian production in lean and normoinsulinemic PCOS subjects.

BMI-associated gene variants in FTO and cardiometabolic and brain disease: obesity or pleiotropy?

Obesity is a causal risk factor for the development of age-related disease conditions, which includes Type 2 diabetes mellitus, cardiovascular disease, and dementia. In genome-wide association studies, genetic variation in FTO is strongly associated with obesity and has been described across different ethnic backgrounds and life stages. To date, much work has been devoted on determining the biological mechanisms via which FTO affects body weight regulation and ultimately contributes to age-related cardiometabolic and brain disease. The main hypotheses of the involved biological mechanisms include the involvement of FTO in habitual food intake and energy expenditure. In this narrative review, our overall aim is to provide an overview on how FTO gene variants could increase the risk of developing age-related disease conditions. Specifically, we will discuss the state of the literature based on the different hypotheses how FTO regulates body weight and ultimately contributes to cardiometabolic disease and brain disease.

Association between rs9930506 polymorphism of the fat mass & obesity-associated (FTO) gene & onset of obesity in Polish adults

BACKGROUND & OBJECTIVES

The fat mass and obesity-associated (FTO) gene is known to be associated with obesity. However, no data are available on the relation between FTO rs9930506 polymorphism and obesity in Polish population. The aim of this study was to evaluate an association between rs9930506 variants of the FTO gene and obesity in Polish adults.

METHODS

The study group consisted of 442 adults, aged 33.9 ±12.7 yr, with mean BMI 27.2 ± 5.4 kg/m2. The following variables were determined for each subject: fasting blood glucose, total cholesterol, LDL-cholesterol, HDL-cholesterol, and triglycerides. Real-time PCR was used to detect the A/G alleles of the rs9939506 polymorphism in the FTO gene. An association between the rs9930506 polymorphism and obesity was determined using codominant, dominant, and recessive models. The odds ratio (OR) was calculated to determine the risk of obesity associated with this polymorphism.

RESULTS

It was observed that the presence of FTO rs9939506 G allele was associated with increased risk for obesity and this association was found significant in both recessive (OR = 1.72, P = 0.014) and co-dominant (OR = 1.36, P = 0.031) models of inheritance. The FTO rs9939506 GG homozygotes had a significantly higher BMI than those with other genotypes.

INTERPRETATION & CONCLUSIONS

This study shows that FTO rs9939506 GG genotype is related to higher BMI and is associated with obesity in Polish adults.

The Generation R Study: Biobank update 2015

The Generation R Study is a population-based prospective cohort study from fetal life until adulthood. The study is designed to identify early environmental and genetic causes and causal pathways leading to normal and abnormal growth, development and health from fetal life, childhood and young adulthood. In total, 9,778 mothers were enrolled in the study. Data collection in children and their parents include questionnaires, interviews, detailed physical and ultrasound examinations, behavioural observations, Magnetic Resonance Imaging and biological samples. Efforts have been conducted for collecting biological samples including blood, hair, faeces, nasal swabs, saliva and urine samples and generating genomics data on DNA, RNA and microbiome. In this paper, we give an update of the collection, processing and storage of these biological samples and available measures. Together with detailed phenotype measurements, these biological samples provide a unique resource for epidemiological studies focused on environmental exposures, genetic and genomic determinants and their interactions in relation to growth, health and development from fetal life onwards.

Variation in the fat mass and obesity-related (FTO) genotype is not associated with body fatness in infants, but possibly with their length

BACKGROUND

Data relating variation at the fat mass and obesity-related (FTO) locus (rs9939609) to fat mass in infancy are inconclusive.

OBJECTIVE

To study relationships between FTO genotype and infant size (at 1 and 12 weeks and at 1 year of age) and body composition (at 1 and 12 weeks).

METHODS

Body composition was assessed using air displacement plethysmography in 207 infants. FTO was genotyped using the TaqMan assay.

RESULTS

The number of risk alleles was related to length at 1 and 12 weeks (P = 0.007-0.033) but not to fat mass. The relationship to length was stronger in boys than in girls.

CONCLUSIONS

Our results suggest that the FTO genotype is not related during infancy to fat mass but is related to length in boys but not in girls.

Early developmental conditioning of later health and disease: physiology or pathophysiology?

Extensive experimental animal studies and epidemiological observations have shown that environmental influences during early development affect the risk of later pathophysiological processes associated with chronic, especially noncommunicable, disease (NCD). This field is recognized as the developmental origins of health and disease (DOHaD). We discuss the extent to which DOHaD represents the result of the physiological processes of developmental plasticity, which may have potential adverse consequences in terms of NCD risk later, or whether it is the manifestation of pathophysiological processes acting in early life but only becoming apparent as disease later. We argue that the evidence suggests the former, through the operation of conditioning processes induced across the normal range of developmental environments, and we summarize current knowledge of the physiological processes involved. The adaptive pathway to later risk accords with current concepts in evolutionary developmental biology, especially those concerning parental effects. Outside the normal range, effects on development can result in nonadaptive processes, and we review their underlying mechanisms and consequences. New concepts concerning the underlying epigenetic and other mechanisms involved in both disruptive and nondisruptive pathways to disease are reviewed, including the evidence for transgenerational passage of risk from both maternal and paternal lines. These concepts have wider implications for understanding the causes and possible prevention of NCDs such as type 2 diabetes and cardiovascular disease, for broader social policy and for the increasing attention paid in public health to the lifecourse approach to NCD prevention.

Relation of fat-mass and obesity-associated gene polymorphism to fat mass content and body mass index in obese children

Fat mass content, fat distribution, and fat-mass and obesity associated (FTO) gene have been reported among a broad spectrum of genetic variation connected with body weight. The aim of our study was to investigate whether the T/A rs9939609 polymorphism of the FTO gene may influence obesity and metabolic indices in children. A 160 children were examined (136 obese and 24 non-obese). The anthropometric measurements and calculations included: height, weight, waist and hip circumference, sum of the thickness of 3 and 10 skin folds, % of fat content, % FAT- BIA , % LBM-BIA. BMI, SDS of BMI, WHR, and WHtR. Fasting plasma total cholesterol (TC), HDL and LDL-cholesterol, triglycerides (TG), oral glucose tolerance test (OGTT), and HOMA-IR were analyzed and the blood pressure were measured. The rs9939609 polymorphism of FTO gene was genotyped by allele-specific real-time polymerase chain- reaction (RT-PCR). We found that the mean concentrations of TC, TG, LDLC, and HOMA-IR were significantly higher, and HDL was lower in the obese than in non-obese children. The presence of TT, but not AA alleles, related to the percentage of fat content, BMI, and z-score of BMI. None of the other anthropometric indices did differ between the children with gene polymorphism and wild homozygous. In conclusion, rs9939609 polymorphism in the fat-mass and obesity-associated gene is associated with BMI and the percent of fat content in children.

The Generation R Study: design and cohort update 2010

The Generation R Study is a population-based prospective cohort study from fetal life until young adulthood. The study is designed to identify early environmental and genetic causes of normal and abnormal growth, development and health during fetal life, childhood and adulthood. The study focuses on four primary areas of research: (1) growth and physical development; (2) behavioural and cognitive development; (3) diseases in childhood; and (4) health and healthcare for pregnant women and children. In total, 9,778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. General follow-up rates until the age of 4 years exceed 75%. Data collection in mothers, fathers and preschool children included questionnaires, detailed physical and ultrasound examinations, behavioural observations, and biological samples. A genome wide association screen is available in the participating children. Regular detailed hands on assessment are performed from the age of 5 years onwards. Eventually, results forthcoming from the Generation R Study have to contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.