Publications by authors named "P A Crabbe"
Objective: Sex steroid concentrations in men are related to body composition and both are determined by genetic and environmental factors. This study investigates heritability estimates of sex steroid serum concentrations and body composition as well as the genetic and environmental components of their interrelation.
Patients: Six hundred and seventy-four men (25-45 years) were included in this study with 274 independent pairs of brothers.
Context: There is a large interindividual variation in serum (free) testosterone (FT) levels in men, underlain in part by genetic components.
Objective: The objective of the study was to explore the hypothesis that this variability results in part from differences in androgen sensitivity and feedback loop set point and assess the role of the androgen receptor (AR) polyglutamine tract polymorphism encoded by a CAG repeat of variable length in exon 1 of the AR gene.
Design/setting/participants: We performed a cross-sectional analysis in two independent populations of healthy men, consisting of 2322 men aged 35-59 yr (Belstress study) and 358 men aged 25-45 yr (Siblos study), respectively.
Objective: The androgen receptor (AR) gene contains a CAG repeat polymorphism coding for a polyglutamine chain, the length of which is inversely correlated with AR transcriptional activity. We explored whether this polymorphism modulates the activities of testosterone (T) related to body composition in elderly men.
Design: We performed cross-sectional analyses using data from a 4-year follow-up study in community-dwelling men aged 75-89 years (n=159).
Objective: Across studies it has been suggested that leptin intervenes as a regulator of bone metabolism. This study assesses the contribution in elderly men of leptin and the Gln223Arg leptin receptor gene (LEPR) polymorphism to the variation in bone homeostasis, in relation to body composition and free estradiol as major confounders.
Design: We performed cross-sectional (n = 270) and longitudinal (mean follow-up 3.
Unlabelled: We studied whether the LRP5 gene contributes to the clinical phenotype of IO in men. Mutation analysis in 66 IO men revealed a range of sequence variants, of which two missense variants were shown to be of functional relevance.
Introduction: Mutations in the LDL receptor-related protein 5 (LRP5) gene have been associated with extreme bone phenotypes, which makes LRP5 a plausible candidate gene for idiopathic osteoporosis (IO).