J Polak, Z Kovacova, C Holst, C Verdich, A Astrup, E Blaak, K Patel, J M Oppert, D Langin, J A Martinez, T I A Sørensen and V Stich
Adiponectin increases insulin sensitivity, protects arterial walls against atherosclerosis, and regulates glucose metabolism, and is decreased in obese, insulin resistant, and type 2 diabetic patients. Adiponectin circulates in plasma as high, medium, and low molecular weight forms (HMW, MMW, and LMW). The HMW form was suggested to be closely associated with insulin sensitivity. This study investigated whether diet-induced changes in insulin sensitivity were associated with changes in adiponectin multimeric complexes.
Twenty obese women with highest and twenty obese women with lowest diet induced changes in insulin sensitivity (responders and non-responders respectively), matched for weight loss (body mass index (BMI)=34.5 (s.d. 2.9) resp. 36.5 kg/m2 (s.d. 4.0) for responders and non-responders), were selected from 292 women who underwent a 10-week low-caloric diet (LCD; 600 kcal/d less than energy requirements). Plasma HMW, MMW, and LMW forms of adiponectin were quantified using Western blot method.
LCD induced comparable weight reduction in responders and non-responders by 8.2 and 7.6 kg. Homeostasis model assessment insulin resistance index decreased by 48.1% in responders and remained unchanged in non-responders. Total plasma adiponectin and the quantity of HMW and MMW remained unchanged in both groups, while LMW increased by 16.3% in non-responders. No differences between both groups were observed at baseline and after the study. Total plasma adiponectin, MMW, and LMW were negatively associated with fasting insulin levels at baseline.
No differences in total plasma adiponectin, HMW, MMW, and LMW forms were observed between responders and non-responders following 10-week LCD, suggesting that adiponectin is not a major determinant of weight loss-induced improvements in insulin sensitivity.
H E Ramos, A Carré, L Chevrier, G Szinnai, E Tron, T L O Cerqueira, J Léger, S Cabrol, O Puel, C Queinnec, N De Roux, L Guillot, M Castanet and M Polak
Within the last two decades, heterozygous loss-of-function PAX8 mutations have been reported in patients with a wide degree of thyroid gland dysfunction and growth despite the presence of identical mutations.
To search for PAX8 mutations in a cohort of patients with congenital hypothyroidism (CH) and various types of thyroid gland defects.
A cross-sectional study was conducted in a cohort of patients.
The French neonatal screening program was used for recruiting patients.
A total of 118 patients with CH, including 45 with familial and 73 with sporadic diseases, were included in this study. The thyroid gland was normal in 23 patients had hypoplasia, 25 had hemithyroid agenesis, 21 had athyreosis, and 21 had ectopy.
We found four different PAX8 mutations (p.R31C, p.R31H, p.R108X, and p.I47T) in ten patients (six patients with CH and four family members), two with sporadic and eight with familial diseases. Imaging studies performed in the index cases showed ectopic thyroid gland (n=2), hypoplasia (n=2), eutopic lobar asymmetry (n=1), and eutopic gland compatible with dyshormonogenesis (n=1). The previously reported p.R31C and the novel p.I47T PAX8 mutations are devoid of activity.
Four different PAX8 mutations were detected in six index patients with CH (ten total subjects). The p.R31C, p.R31H, and p.R108X mutations have been reported. The novel p.I47T PAX8 mutation presented loss of function leading to CH. Thyroid ectopy was observed in two cases of PAX8 (p.R31H) mutation, a finding that has not been reported previously. We observed a high inter-individual and intra-familial variability of the phenotype in PAX8 mutations, underlining that population genetic studies for CH should include patients with various clinical presentations.
R Teissier, I Flechtner, A Colmenares, K Lambot-Juhan, G Baujat, C Pauwels, D Samara-Boustani, J Beltrand, A Simon, C Thalassinos, H Crosnier, H Latrech, G Pinto, M Le Merrer, V Cormier-Daire, J C Souberbielle and M Polak
The prevalence of severe primary IGF1 deficiency (IGFD) is unclear. IGFD must be identified promptly as treatment with recombinant human IGF1 (rhIGF1) is now available. Our objective was to characterize and assess the prevalence of severe primary IGFD in a large cohort of patients evaluated for short stature at a pediatric endocrinology unit in France.
Observational study in a prospective cohort.
Consecutive patients referred to our unit between 2004 and 2009 for suspected slow statural growth were included. Patients were classified into eight etiological categories. IGFD was defined by height ≤−3 SDS, serum IGF1 levels <2.5th percentile, GH sufficiency, and absence of causes of secondary IGFD.
Out of 2546 patients included, 337 (13.5%) were born small for gestational age and 424 (16.9%) had idiopathic short stature. In these two categories, we identified 30 patients who met our criterion for IGFD (30/2546, 1.2%). In these 30 patients, we assessed the response to IGF1 generation test, time course of IGF1 levels, and efficiency of GH replacement therapy. The results indicated that only four of the 30 children were definite or possible candidates for rhIGF1 replacement therapy.
The prevalence of severe primary IGFD defined using the standard criterion for rhIGF1 treatment was 1.2%, and only 0.2% of patients were eligible for rhIGF1 therapy.
I Flechtner, K Lambot-Juhan, R Teissier, A Colmenares, G Baujat, J Beltrand, Z Ajaltouni, C Pauwels, G Pinto, D Samara-Boustani, A Simon, C Thalassinos, M Le Merrer, V Cormier-Daire and M Polak
To assess the prevalence of skeletal dysplasias (SDs) in patients with idiopathic short stature (ISS) or small for gestational age (SGA) status.
Rare Endocrine/Growth Diseases Center in Paris, France.
A prospective study on consecutive patients with ISS and SGA enrolled from 2004 to 2009.
We used a standardized workup to classify patients into well-established diagnostic categories. Of 713 patients with ISS (n=417) or SGA status (n=296), 50.9% underwent a skeletal survey. We chose patients labeled normal or with a prepubertal slowdown of growth as a comparison group.
Diagnoses were ISS (16.9%), SGA (13.5%), normal growth (24.5%), transient growth rate slowing (17.3%), endocrine dysfunction (12%), genetic syndrome (8.9%), chronic disease (5.1%), and known SD (1.8%). SD was found in 20.9% of SGA and 21.8% ISS patients and in only 13.2% in our comparison group. SD prevalence was significantly higher in the ISS group than in the comparison group, especially (50%) for patients having at least one parent whose height was <−2 SDS. Dyschondrosteosis and hypochondroplasia were the most frequently identified SD, and genetic anomaly was found in 61.5 and 30% respectively. Subtle SD was found equally in the three groups and require long-term growth follow-up to evaluate the impact on final height.
SD may explain more than 20% of cases of growth retardation ascribed to ISS or SGA, and this proportion is higher when parental height is <−2 SDS. A skeletal survey should be obtained in patients with delayed growth in a context of ISS or SGA.