The Characteristics of Care Provided to Population(s) in Precarious Situations in 2015. A Preliminary Study on the Universal Health Cover in France

Background: The French Universal Health Cover (CMU) aims to compensate for inequalities between precarious and non-precarious populations, enabling the former to access to free healthcare. These measures rely on the principle that precarious populations' health improves if healthcare is free. We designed a study to examine whether CMU fails to compensate for inequalities in reimbursed drugs prescriptions in precarious populations. Material and method: This retrospective pharmaco-epidemiological study compared the Defined Daily Dose relative to different reimbursed drugs prescribed by general practitioners (GPs) to precarious and non-precarious patients in France in 2015. Data were analysed using Mann-Whitney tests. Findings: 6 out of 20 molecules were significantly under-reimbursed in precarious populations. 2 were over-reimbursed. The 12 remaining molecules did not differ between groups. Interpretation: The under-reimbursement of atorvastatin, rosuvastatin, tamsulosine and timolol reflects well-documented epidemiological differences between these populations. In contrast, the equal reimbursement of amoxicillin, pyostacine, ivermectin, salbutamol and tiopropium is likely an effect of lack of compensation for inequalities. Precarious patients are more affected by diseases that these molecules target (e.g., chronic bronchitis, bacterial pneumonia, cutaneous infections). This could also be the case for the equal and under-reimbursement of insulin glargine and metformin (targeting diabetes), respectively, although this has to be considered with caution. In conclusion, the French free healthcare cover does not fail to compensate for all but only for some selective inequalities in access to reimbursed drugs prescriptions. These results are discussed with respect to the interaction of the doctor-patient relationship and the holistic nature of primary care, potentially triggering burnout and empathy decrease and negatively impacting the quality of care in precarious populations.

Tyrphostin AG126 exerts neuroprotection in CNS inflammation by a dual mechanism

The putative protein tyrosine kinase (PTK) inhibitor tyrphostin AG126 has proven beneficial in various models of inflammatory disease. Yet molecular targets and cellular mechanisms remained enigmatic. We demonstrate here that AG126 treatment has beneficial effects in experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis. AG126 alleviates the clinical symptoms, diminishes encephalitogenic Th17 differentiation, reduces inflammatory CNS infiltration as well as microglia activation and attenuates myelin damage. We show that AG126 directly inhibits Bruton's tyrosine kinase (BTK), a PTK associated with B cell receptor and Toll-like receptor (TLR) signaling. However, BTK inhibition cannot account for the entire activity spectrum. Effects on TLR-induced proinflammatory cytokine expression in microglia involve AG126 hydrolysis and conversion of its dinitrile side chain to malononitrile (MN). Notably, while liberated MN can subsequently mediate critical AG126 features, full protection in EAE still requires delivery of intact AG126. Its anti-inflammatory potential and especially interference with TLR signaling thus rely on a dual mechanism encompassing BTK and a novel MN-sensitive target. Both principles bear great potential for the therapeutic management of disturbed innate and adaptive immune functions.

Common nonsynonymous variants in PCSK1 confer risk of obesity

Mutations in PCSK1 cause monogenic obesity. To assess the contribution of PCSK1 to polygenic obesity risk, we genotyped tag SNPs in a total of 13,659 individuals of European ancestry from eight independent case-control or family-based cohorts. The nonsynonymous variants rs6232, encoding N221D, and rs6234-rs6235, encoding the Q665E-S690T pair, were consistently associated with obesity in adults and children (P = 7.27 x 10(-8) and P = 2.31 x 10(-12), respectively). Functional analysis showed a significant impairment of the N221D-mutant PC1/3 protein catalytic activity.

Evaluating the association of FAAH common gene variation with childhood, adult severe obesity and type 2 diabetes in the French population

OBJECTIVE

The endocannabinoid pathway is involved in eating behavior and body weight regulation in both animals and humans. The association of a missense polymorphism (Pro129Thr) in FAAH gene with overweight/obesity has been recently questioned.

SUBJECTS AND METHODS

To evaluate the contribution of the FAAH gene variation in polygenic obesity and type 2 diabetes mellitus (T2DM) in the French population, we investigated the entire FAAH locus. We selected and genotyped ten tagged single nucleotide polymorphisms (SNPs) in 635 obese children, 896 morbidly obese adults, 2,238 T2DM subjects and 1,340 control subjects, all of French European origin. Case control association tests were performed using logistic regression models.

RESULTS

Nominal evidences of association were observed for rs6429600, rs324419, rs324418, rs2295633, rs7520850 and risk for class III adult obesity (0,001 < p < 0.04). The rs324420 (Pro129Thr) was nominally associated with class III adult obesity (ORadditive = 0.79 (95% CI 0.67-0.93), p = 0.005; ORdominant = 0.76 (95% CI 0.63-0.92), p = 0.005), Pro129 being the obesity risk allele. These associations did not remain significant after Bonferroni correction for multiple testing. There was no significant association between FAAH SNPs and risk for childhood obesity or T2DM.

CONCLUSION

Our results in 5,109 subjects suggest that FAAH Pro129Thr polymorphism may modestly contribute to class III adult obesity in the French population. Further validation is needed to precise the role of this gene variant in obesity susceptibility background.

A genome-wide association study identifies novel risk loci for type 2 diabetes

Type 2 diabetes mellitus results from the interaction of environmental factors with a combination of genetic variants, most of which were hitherto unknown. A systematic search for these variants was recently made possible by the development of high-density arrays that permit the genotyping of hundreds of thousands of polymorphisms. We tested 392,935 single-nucleotide polymorphisms in a French case-control cohort. Markers with the most significant difference in genotype frequencies between cases of type 2 diabetes and controls were fast-tracked for testing in a second cohort. This identified four loci containing variants that confer type 2 diabetes risk, in addition to confirming the known association with the TCF7L2 gene. These loci include a non-synonymous polymorphism in the zinc transporter SLC30A8, which is expressed exclusively in insulin-producing beta-cells, and two linkage disequilibrium blocks that contain genes potentially involved in beta-cell development or function (IDE-KIF11-HHEX and EXT2-ALX4). These associations explain a substantial portion of disease risk and constitute proof of principle for the genome-wide approach to the elucidation of complex genetic traits.

Genotype-by-nutrient interactions assessed in European obese women. A case-only study

BACKGROUND

The development of obesity is influenced by both genetic and environmental risk factors. Whereas changes in the environment appear to be responsible for the increasing prevalence of obesity, genetic factors interacting with environmental factors would contribute to explain obesity onset and severity.

AIM

To explore epidemiologic genotype-by-nutrient interactions in obesity.

METHODS

A total of 42 polymorphisms of 26 candidate genes for obesity were genotyped in 549 adult obese women recruited from eight European centres in a case-only study. The nutritional variables assessed in this study were the dietary fibre intake (grams per day), the ratio of dietary polyunsaturated fat to saturated fat (P:S ratio) and the percentage of energy derived from fat in the diet as calculated from a weighed three-day food record (%E). Under the assumption of genotype-nutrient independence in the population, the odds ratio calculated in a sample of obese women would indicate the existence of genotype-by-nutrient interactions, measured as deviations from the multiplicative effects of the genetic and the nutrient factors separately.

RESULTS

No new but confirmaty evidences for genotype-by-nutrient interactions in obesity were detected in this case-only study. The test of interaction between fibre intake and the -514 C > T polymorphism of the hepatic lipase gene (LIPC) yielded P-values of 0.01 across different statistical models. Likewise, the -11377G > C polymorphism of the adiponectin gene (ADIPOQ) and the -681 C > G polymorphism of the PPARG3 gene might interact with the percentage of energy derived from fat in the diet for the development of obesity (P-values in the range of 0.01-0.05 across different statistical models). The P-values were not adjusted for multiple testing, so these results should be considered with caution.

CONCLUSIONS

Although the use of obese-only samples is theoretically a useful approach to detect interactions, few genotype-by-nutrient interactions have been suggested in obese European women after the analysis of candidate polymorphisms and the selected nutrient variables. The most remarkable multiplicative interaction found in this study refers to the combination of the hepatic lipase gene polymorphism -514 C > T and fibre intake.

Distinct impaired regulation of SOCS3 and long and short isoforms of the leptin receptor in visceral and subcutaneous fat of lean and obese women

Animal studies have illustrated the importance of the expression in adipose tissue of the leptin receptor (OB-R), and of SOCS3 an inhibitor of the leptin signaling pathway, in body weight regulation. The aim of the present study was to investigate in human adipose tissues of the same patients the OB-R isoforms and SOCS3 expression. Subcutaneous and omental adipose tissues were obtained from 6 lean and 18 morbidly obese women. The long isoform OB-Rb mRNA mediating leptin signaling, and SOCS3 mRNA are abundantly present in the subcutaneous fat of lean women, but are 90% and 70% decreased (P<0.0001) in obese women. In visceral fat from lean and obese women, both OB-Rb and SOCS3 mRNA are detected at very low levels. Subcutaneous/visceral ratios for OB-Ra the short OB-R isoform, OB-Rb, and SOCS3 mRNA abundance strongly correlate with the insulin sensitivity index, HOMA-% S, (r=0.49, P<0.0001, r=0.42, P=0.0002 and r=0.38, P=0.0002, respectively) in both lean and obese patients without type 2 diabetes. The near absence of OB-Rb mRNA and the similarly decreased SOCS3 expression in obese adipose tissue may reflect a defective leptin signaling pathway that could play a role in the impairment of insulin sensitivity associated with excess adiposity.

Genetic polymorphisms and weight loss in obesity: a randomised trial of hypo-energetic high- versus low-fat diets

Objectives:

To study if genes with common single nucleotide polymorphisms (SNPs) associated with obesity-related phenotypes influence weight loss (WL) in obese individuals treated by a hypo-energetic low-fat or high-fat diet.

Design:

Randomised, parallel, two-arm, open-label multi-centre trial.

Setting:

Eight clinical centres in seven European countries.

Participants:

771 obese adult individuals.

Interventions:

10-wk dietary intervention to hypo-energetic (−600 kcal/d) diets with a targeted fat energy of 20%–25% or 40%–45%, completed in 648 participants.

Outcome Measures:

WL during the 10 wk in relation to genotypes of 42 SNPs in 26 candidate genes, probably associated with hypothalamic regulation of appetite, efficiency of energy expenditure, regulation of adipocyte differentiation and function, lipid and glucose metabolism, or production of adipocytokines, determined in 642 participants.

Results:

Compared with the noncarriers of each of the SNPs, and after adjusting for gender, age, baseline weight and centre, heterozygotes showed WL differences that ranged from −0.6 to 0.8 kg, and homozygotes, from −0.7 to 3.1 kg. Genotype-dependent additional WL on low-fat diet ranged from 1.9 to −1.6 kg in heterozygotes, and from 3.8 kg to −2.1 kg in homozygotes relative to the noncarriers. Considering the multiple testing conducted, none of the associations was statistically significant.

Conclusions:

Polymorphisms in a panel of obesity-related candidate genes play a minor role, if any, in modulating weight changes induced by a moderate hypo-energetic low-fat or high-fat diet.

Background: Obesity is an important cause of death and disease, particularly in the developed world. It is understood that both environmental and genetic factors contribute towards obesity. Numerous studies have associated particular gene variants with a tendency towards obesity, but it is not known whether such gene variants affect the degree to which obese individuals will lose weight when dieting.

What this trial shows: As part of a randomised trial, 771 participants were assigned to one of two different low-energy diets for 10 weeks: one low in fat or one high in fat. The researchers then did a genetic analysis of 642 participants completing the intervention, to find out whether any of 42 distinct genetic variations in 26 genes were associated with weight loss in the trial. The genetic variants were chosen for study as they were known or already thought to be associated with appetite regulation or various aspects of metabolism and fat tissue development and function. The investigators found that none of the genetic variants studied had a significant association with weight loss in the trial. It was also seen that the majority of genetic variants were not associated with efficacy of one dietary intervention over another.

Strengths and limitations: Although a large number of participants was recruited into the trial, the genetic analysis involved multiple comparisons—168 tests of 42 genetic variants. This increases the likelihood that any significant associations found could have resulted from chance alone. Significant associations from this study will require additional confirmation in larger studies.

Contribution to the evidence: This study adds data indicating that variation in the genes studied did not have an important influence on weight loss.

The INS VNTR locus does not associate with smallness for gestational age (SGA) but interacts with SGA to increase insulin resistance in young adults

CONTEXT

Both adverse intrauterine events and genetic background have been suggested to promote insulin resistance in subjects born small for gestational age (SGA). Among candidate genes that potentially influence both fetal growth and glucose metabolism is insulin. The potential effect of the insulin gene VNTR (INS) on birth weight has been controversial so far.

OBJECTIVE

The present association study aimed at testing for the contribution of the INS VNTR locus on birth weight and on the metabolic profile of young adults born SGA (mean age, 22 yr). Two groups of subjects were selected on birth data: SGA (birth weight < 10th percentile; n = 735), and appropriate for gestational age (AGA; birth weight between 25th and 75th percentiles; n = 886). All subjects were genotyped for rs689 A/T single nucleotide polymorphism, in complete linkage disequilibrium with the INS VNTR classes I and III, respectively.

RESULTS

Class I INS frequencies were similar in the two groups (70% in AGA; 72% in SGA; P = 0.42). There was significant effect on mean birth weight in neither SGA (P = 0.99) nor AGA (P = 0.18). Although the INS VNTR locus did not associate with anomalies of insulin resistance indices in the AGA group, in the SGA group, INS VNTR class III allele was associated with higher insulin resistance (quantitative insulin sensitivity check index = 0.38 vs. 0.39; P = 0.05). Furthermore, there was evidence of an interaction between the SGA/AGA status and INS VNTR locus on insulin resistance indices (P = 0.01) in a multivariate analysis.

CONCLUSION

The INS VNTR locus does not associate in a major way with SGA in the French population. However, our data support an interaction between severe fetal growth restriction and INS VNTR locus, which were associated with insulin resistance in young adults born SGA.

Genetic analysis of ADIPOR1 and ADIPOR2 candidate polymorphisms for type 2 diabetes in the Caucasian population

Adiponectin is a metabolic link between adipose tissue and insulin action, mediating part of obesity-associated insulin resistance and type 2 diabetes. Two adiponectin receptors have been identified, and we investigated whether sequence variations in adiponectin receptor 1 (ADIPOR1) and adiponectin receptor 2 (ADIPOR2) genes could contribute to the genetic risk for type 2 diabetes in a case-control study of 1,498 Caucasian subjects. We sequenced the putative functional regions of the two genes in 48 subjects and selected single nucleotide polymorphisms (SNPs) from the public database. Five SNPs in ADIPOR1 and 12 in ADIPOR2 were tested for association with type 2 diabetes. No SNP of ADIPOR1 showed association in any of the samples from the French population. In contrast, three SNPs of ADIPOR2 showed nominal evidence for association with type 2 diabetes before correction for multiple testing (odds ratio [OR] 1.29-1.37, P = 0.034-0.014); only rs767870, located in intron 6, was replicated in an additional diabetes dataset (n = 636, OR 1.29, P = 0.020) with significant allelic association from the overall meta-analysis of 2,876 subjects (adjusted OR 1.25 [95% CI 1.07-1.45], P = 0.0051). In conclusion, our data suggest a modest contribution of ADIPOR2 variants in diabetes risk in the French population.

Variants of ENPP1 are associated with childhood and adult obesity and increase the risk of glucose intolerance and type 2 diabetes

We identified a locus on chromosome 6q16.3-q24.2 (ref. 1) associated with childhood obesity that includes 2.4 Mb common to eight genome scans for type 2 diabetes (T2D) or obesity. Analysis of the gene ENPP1 (also called PC-1), a candidate for insulin resistance, in 6,147 subjects showed association between a three-allele risk haplotype (K121Q, IVS20delT-11 and A-->G+1044TGA; QdelTG) and childhood obesity (odds ratio (OR) = 1.69, P = 0.0006), morbid or moderate obesity in adults (OR = 1.50, P = 0.006 or OR = 1.37, P = 0.02, respectively) and T2D (OR = 1.56, P = 0.00002). The Genotype IBD Sharing Test suggested that this obesity-associated ENPP1 risk haplotype contributes to the observed chromosome 6q linkage with childhood obesity. The haplotype confers a higher risk of glucose intolerance and T2D to obese children and their parents and associates with increased serum levels of soluble ENPP1 protein in children. Expression of a long ENPP1 mRNA isoform, which includes the obesity-associated A-->G+1044TGA SNP, was specific for pancreatic islet beta cells, adipocytes and liver. These findings suggest that several variants of ENPP1 have a primary role in mediating insulin resistance and in the development of both obesity and T2D, suggesting that an underlying molecular mechanism is common to both conditions.

Hypoadiponectinaemia and high risk of type 2 diabetes are associated with adiponectin-encoding (ACDC) gene promoter variants in morbid obesity: evidence for a role of ACDC in diabesity

AIMS/HYPOTHESIS

Morbid obesity (BMI>40 kg/m(2)) affecting 0.5-5% of the adult population worldwide is a major risk factor for type 2 diabetes. We aimed to elucidate the genetic bases of diabetes associated with obesity (diabesity), and to analyse the impact of corpulence on the effects of diabetes susceptibility genes.

METHODS

We genotyped known single nucleotide polymorphisms (SNPs) in the adiponectin-encoding adipocyte C1q and collagen-domain-containing (ACDC) gene (-11,391G>A, -11,377C>G, +45T>G and +276G>T), the peroxisome proliferator-activated receptor gamma (PPARG) Pro12Ala SNP and ACDC exon 3 variants in 703 French morbidly obese subjects (BMI 47.6+/-7.4 kg/m(2)), 808 non-obese subjects (BMI<30 kg/m(2)) and 493 obese subjects (30< or =BMI<40 kg/m(2)).

RESULTS

Two 5'-ACDC SNPs -11,391G>A, -11,377C>G were associated with adiponectin levels (p=0.0003, p=0.008) and defined a "low-level" haplotype associated with decreased adiponectin levels (p=0.0002) and insulin sensitivity (p=0.01) and with a risk of type 2 diabetes that was twice as high (p=0.002). In contrast, the prevalence of the PPARG Pro12Ala was identical in diabetic and normoglycaemic morbidly obese subjects. The PPARG Pro12 allele only displayed a trend of association with type 2 diabetes in the non-obese group. ACDC exon 3 variants were associated with type 2 diabetes in the non-obese group only (odds ratio 7.85, p<0.0001). In contrast, the 5'-ACDC "low-level" haplotype was associated with type 2 diabetes in obese and morbidly obese subjects (odds ratio 1.73 and 1.92) but not in non-obese individuals.

CONCLUSIONS/INTERPRETATION

These data clarify the contribution of the 5'-ACDC SNPs to the risk of diabesity. Their interaction with corpulence suggests for the first time a different genetic profile of type 2 diabetes in morbidly obese patients compared with in less obese individuals.

Analysis of sequence variability in the CART gene in relation to obesity in a Caucasian population

Background

Cocaine and amphetamine regulated transcript (CART) is an anorectic neuropeptide located principally in hypothalamus. CART has been shown to be involved in control of feeding behavior, but a direct relationship with obesity has not been established. The aim of this study was to evaluate the effect of polymorphisms within the CART gene with regards to a possible association with obesity in a Caucasian population.

Results

Screening of the entire gene as well as a 3.7 kb region of 5' upstream sequence revealed 31 SNPs and 3 rare variants ; 14 of which were subsequently genotyped in 292 French morbidly obese subjects and 368 controls. Haplotype analysis suggested an association with obesity which was found to be mainly due to SNP-3608T>C (rs7379701) (p = 0.009). Genotyping additional cases and controls also of European Caucasian origin supported further this possible association between the CART SNP -3608T>C T allele and obesity (global p-value = 0.0005). Functional studies also suggested that the SNP -3608T>C could modulate nuclear protein binding.

Conclusion

CART SNP -3608T>C may possibly contribute to the genetic risk for obesity in the Caucasian population. However confirmation of the importance of the role of the CART gene in energy homeostasis and obesity will require investigation and replication in further populations.

Is glutamate decarboxylase 2 (GAD2) a genetic link between low birth weight and subsequent development of obesity in children?

Low birth weight is a risk factor for obesity and type 2 diabetes. The fetal insulin hypothesis proposes that low birth weight might be mediated partly by genetic factors that impair insulin secretion/sensitivity during the fetal stage, as shown for glucokinase, the ATP-sensitive K+ channel subunit Kir6.2, and the small heterodimer partner genes. Glutamic acid decarboxylase 2 gene (GAD2) overexpression impairs insulin secretion in animals. Recently, polymorphisms in the GAD2 gene were associated with adult morbid obesity. In the present study, we investigated potential effects of the functional -243 A-->G polymorphism in the 5' promoter region of the GAD2 gene on fetal growth, insulin secretion, food intake, and risk of obesity in 635 French Caucasian severely obese children from three different medical centers. The case/control study confirmed the association between the GAD2 single-nucleotide polymorphism (SNP) -243 A-->G and obesity (odds ratio, 1.25; P = 0.04). In addition, SNP -243 GG children carriers showed a 270 g lower birth weight and a 1.5 cm lower birth height compared with AA carriers (P = 0.009 and P = 0.013, respectively). The relation between birth weight and Z score of BMI was linear in AA carrier children (P = 0.00001) and quadratic (U-shaped curve) in AG/GG carrier children (P = 0.0009). G allele children carriers presented a trend toward lower insulinogenic index with 25% reduction of insulin secretion in response to glucose load compared with A carriers (P = 0.09). Eighteen percent of GG obese carriers vs. 5.7% of AA carriers reported binge eating phenotype (P = 0.04). These results confirm the association between GAD2-243 promoter SNP and the risk for obesity and suggest that GAD2 may be a polygenic component of the complex mechanisms linking birth weight to further risk for metabolic diseases, possibly involving the pleiotropic effect of insulin on fetal growth and later on feeding behavior.

Polymorphisms in the amino acid transporter solute carrier family 6 (neurotransmitter transporter) member 14 gene contribute to polygenic obesity in French Caucasians

Positional candidate gene analysis of the obesity-linked chromosome Xq24 locus identified two obesity-associated single nucleotide polymorphisms (SNPs) in the membrane amino acid transporter encoding the SLC6A14 (solute carrier family 6 [neurotransmitter transporter], member 14) gene in the Finnish population. Since we previously reported a modest evidence of linkage for this region in French obese families, we analyzed these SNPs in 1,267 obese adult case and 649 lean control subjects. SNPs 20649 C>T (odds ratio 1.23, 95% CI 1.04-1.45; P = 0.013) and 22510 C>G (1.36, 1.16-1.59; P = 0.0001) were shown to be associated with obesity in the French population. In addition, pedigree disequilibrium test results showed a modest excess of both at-risk SNP alleles in affected offspring (P = 0.05 and P = 0.08 for SNPs 20649 C>T and 22510 C>G, respectively). The SNP 22510 C>G at-risk G allele was associated, both in adult women with moderate obesity and in 234 obese girls, with higher body fat and modified perception of hunger and satiety (0.003 < P < 0.06). In conclusion, these data confirm an association of the SLC6A14 gene locus with obesity.

GAD2 on chromosome 10p12 is a candidate gene for human obesity

The gene GAD2 encoding the glutamic acid decarboxylase enzyme (GAD65) is a positional candidate gene for obesity on Chromosome 10p11-12, a susceptibility locus for morbid obesity in four independent ethnic populations. GAD65 catalyzes the formation of gamma-aminobutyric acid (GABA), which interacts with neuropeptide Y in the paraventricular nucleus to contribute to stimulate food intake. A case-control study (575 morbidly obese and 646 control subjects) analyzing GAD2 variants identified both a protective haplotype, including the most frequent alleles of single nucleotide polymorphisms (SNPs) +61450 C>A and +83897 T>A (OR = 0.81, 95% CI [0.681-0.972], p = 0.0049) and an at-risk SNP (-243 A>G) for morbid obesity (OR = 1.3, 95% CI [1.053-1.585], p = 0.014). Furthermore, familial-based analyses confirmed the association with the obesity of SNP +61450 C>A and +83897 T>A haplotype (chi(2) = 7.637, p = 0.02). In the murine insulinoma cell line betaTC3, the G at-risk allele of SNP -243 A>G increased six times GAD2 promoter activity (p < 0.0001) and induced a 6-fold higher affinity for nuclear extracts. The -243 A>G SNP was associated with higher hunger scores (p = 0.007) and disinhibition scores (p = 0.028), as assessed by the Stunkard Three-Factor Eating Questionnaire. As GAD2 is highly expressed in pancreatic beta cells, we analyzed GAD65 antibody level as a marker of beta-cell activity and of insulin secretion. In the control group, -243 A>G, +61450 C>A, and +83897 T>A SNPs were associated with lower GAD65 autoantibody levels (p values of 0.003, 0.047, and 0.006, respectively). SNP +83897 T>A was associated with lower fasting insulin and insulin secretion, as assessed by the HOMA-B% homeostasis model of beta-cell function (p = 0.009 and 0.01, respectively). These data support the hypothesis of the orexigenic effect of GABA in humans and of a contribution of genes involved in GABA metabolism in the modulation of food intake and in the development of morbid obesity.

[Results of fine needle aspiration biopsy, frozen section diagnosis and definite histological results in thyroid pathology. Report of 163 cases]

INTRODUCTION

In thyroid diseases, the place of fine needle aspiration biopsy still continues to be discussed: the sensibility and specificity vary greatly in the literature. Frozen section diagnosis is necessary to form a diagnostic strategy. The objective of this study was compare the results of fine needle aspiration biopsy, frozen section diagnosis, and definitive histologic results in a population of 163 patients and to draw conclusions about treatment.

MATERIAL AND METHOD

From 1994 to 1999, 163 patients (132 females and, 31 males) undergoing thyroid surgery were included in this retrospective study, after a standard preoperative work-up. Those with a single palpable nodule and hypofixation on scintigraphy underwent fine needle aspiration before surgery. These results were compared with the definitive histologic results.

RESULTS

A loboisthmectomy was performed in 88 cases (54%), a subtotal thyroidectomy in 34 cases (21%), and a total thyrodectomy in 41 cases (25%). In the latter group, an associated neck dissection was performed in 18 cases (11%); a frozen section diagnosis was obtained in all cases of thyroid nodules. This study demonstrated a single nodule in 97 cases (60%), multiple nodules in 27 cases (17%), multinodular goitre in 34 cases (21%), and 5 Basedow diseases (3%). Sixty-two cases (38%) of thyroid nodules underwent fine needle aspiration before surgery. In 25 cases (15%), definitive pathology showed a malignant lesion. The frozen section diagnosis had a sensitivity of 73% and a specificity of 99%, and the fine needle aspiration biopsy had a sensitivity of 40% and a specificity of 100%.

CONCLUSION

The authors propose fine needle aspiration biopsy in the following cases: a single palpable nodule and hypofixation on scintigraphy or a surgical contra indication; and direct surgery in symptomatic thyroid disease or if there are one or several full nodules > 2 cm. In near future, these indications will be modified with the increasing reliability of fine needle aspiration biopsy.

Mutations in the glucokinase regulatory protein gene in 2p23 in obese French caucasians

AIMS/HYPOTHESIS

Glucokinase regulatory protein (GKRP) controls the activity of glucokinase in liver but possibly also in some areas of the central nervous system, suggesting that it could play a role in body mass control. Its gene is located in a region (2p21-23) linked to serum leptin levels. Our goal was to investigate whether mutations in the GKRP gene were associated with obesity.

METHODS

Mutations were sought in the GKRP gene of 57 patients from the families of the French genome-wide scan for obesity that contributed most to the positive LOD score with 2p21-23. The identified mutations were further sought in 720 unrelated obese individuals and 384 individuals of normal weight and their effect on the properties of recombinant GKRP were investigated.

RESULTS

The most frequent mutation (Pro446Leu) had a similar allele frequency in the obese (0.63) and normal weight (0.64) subjects and did not affect the properties of GKRP. Similarly, no effect on the properties of GKRP was observed with Arg590Tyr, found in 10 out of 720 obese subjects and in 2 out of 384 control subjects (p=0.18). Mutation Arg227Stop was found in one obese family and in 1 out of 384 control subjects and led to an insoluble protein. Mutation Arg518Gln, replacing a conserved residue, led to a marked decrease in the affinity of GKRP for both fructose 6-phosphate and fructose 1-phosphate and to a destabilization of GKRP. However, this mutation did not co-segregate with obesity in the single family in which it was found.

CONCLUSIONS/INTERPRETATION

Mutations that affect the properties of GKRP are found in the French population, but they do not seem to account for the linkage between the 2p23 locus and quantitative markers of obesity.

Islet-brain1/C-Jun N-terminal kinase interacting protein-1 (IB1/JIP-1) promoter variant is associated with Alzheimer's disease

Islet-brain1 (IB1) or c-Jun NH2 terminal kinase interacting protein-1 (JIP-1), the product of the MAPK8IP1 gene, functions as a neuronal scaffold protein to allow signalling specificity. IB1/JIP-1 interacts with many cellular components including the reelin receptor ApoER2, the low-density lipoprotein receptor-related protein (LRP), kinesin and the Alzheimer's amyloid precursor protein. Coexpression of IB1/JIP-1 with other components of the c-Jun NH2 terminal-kinase (JNK) pathway activates the JNK activity; conversely, selective disruption of IB1/JIP-1 in mice reduces the stress-induced apoptosis of neuronal cells. We therefore hypothesized that IB1/JIP-1 is a risk factor for Alzheimer's disease (AD). By immunocytochemistry, we first colocalized the presence of IB1/JIP-1 with JNK and phosphorylated tau in neurofibrillary tangles. We next identified a -499A>G polymorphism in the 5' regulatory region of the MAPK8IP1 gene. In two separate French populations the -499A>G polymorphism of MAPK8IP1 was not associated with an increased risk to AD. However, when stratified on the +766C>T polymorphism of exon 3 of the LRP gene, the IB1/JIP-1 polymorphism was strongly associated with AD in subjects bearing the CC genotype in the LRP gene. The functional consequences of the -499A>G polymorphism of MAPK8IP1 was investigated in vitro. In neuronal cells, the G allele increased transcriptional activity and was associated with an enhanced binding activity. Taken together, these data indicate that the increased transcriptional activity in the presence of the G allele of MAPK8IP1 is a risk factor to the onset of in patients bearing the CC genotype of the LRP gene.

Genetics of obesity

Obesity is a typical common multifactorial disease in which environmental and genetic factors interact. In rare cases of severe obesity with childhood onset, a single gene has a major effect in determining the occurrence of obesity, with the environment having only a permissive role in the severity of the phenotype. Exceptional mutations of the leptin gene and its receptor, pro-opiomelanocortine (POMC), prohormone convertase 1 (PC1) and more frequently, mutations in the melanocortin receptor 4 (1 to 4% of very obese cases) have been described. All these obesity genes encode proteins that are strongly connected as part of the same loop of the regulation of food intake. They all involve the leptin axis and one of its hypothalamic targets; the melanocortin pathway. Pathways of bodyweight regulation involved in monogenic forms of obesity might represent targets for future drug development. Successful leptin protein replacement in a leptin-deficient child has contributed to the validation of the usefulness of gene screening in humans. However, the individual variability in response to leptin treatment might be related to genetic variability. The efficiency of leptin itself or of small-molecule agonists of the leptin receptor should be studied in relation with genetic variations in the leptin gene promoter. The most common forms of obesity are polygenic. Two general approaches have been used to date in the search for genes underlying common polygenic obesity in humans. The first approach focuses on selected genes having some plausible role in obesity on the basis of their known or presumed biological role. This approach yielded putative susceptibility genes with only small or uncertain effects. The second approach attempts to map genes purely by position and requires no presumptions on the function of genes. Genome-wide scans identify chromosomal regions showing linkage with obesity in large collections of nuclear families. Genome-wide scans in different ethnic populations have localized major obesity loci on chromosomes 2, 5, 10, 11 and 20. Susceptibility gene(s) for obesity may be positionally cloned in the intervals of linkage. The candidate gene and positional cloning of major obesity-linked regions approaches are discussed in this paper.

[Middle ear adenoma: report of two cases and review of the literature]

INTRODUCTION

Middle ear adenoma is an uncommon tumor. We report two cases and review the relevant literature concerning this rare entity.

MATERIAL AND METHODS

Two patients with a middle ear adenoma were operated on in our department. Pre- and postoperative data concerning clinical examination, audiometry, and radiology were obtained. Information concerning intraoperative observations and the pathological examination were also gathered.

RESULTS AND DISCUSSION

The diagnosis of middle ear adenomas is based on clinical, radiological, and pathological confrontation. The microscopic examination should be combined with histochemical and immuno-histochemical methods in order to evidence the glandular and neuroendocrin components of these lesions.

CONCLUSION

Today, classified as a benign epithelial tumor, the middle ear adenoma is associated with an excellent prognosis provided total excision.

Single-nucleotide polymorphism haplotypes in the both proximal promoter and exon 3 of the APM1 gene modulate adipocyte-secreted adiponectin hormone levels and contribute to the genetic risk for type 2 diabetes in French Caucasians

Adiponectin (ACRP30), an adipocyte-secreted protein encoded by the APM1 gene, is known to modulate insulin sensitivity and glucose homeostasis, those effects protecting obese mice from diabetes. Plasma adiponectin levels correlate well with insulin sensitivity in humans, and are decreased in both type 2 diabetes (T2D) and obesity. We screened for single-nucleotide polymorphisms (SNPs) the APM1 gene coding and 5' sequences in 40 French Caucasians: 12 SNPs and 4 rare non-synonymous mutations of exon 3 were detected. The 10 most frequent SNPs were genotyped in 1373 T2D and obese French Caucasian subjects and in all subjects available from 148 T2D multiplex families. The screening for rare mutations of exon 3 was extended to 1246 T2D and obese French subjects and to the members of the 148 T2D multiplex families. A haplotype including SNPs -11391 and -11377, both located in the 5' sequences, was associated with adiponectin levels (P<0.0001) and with T2D (P=0.004). The presence of at least one non-synonymous mutation in exon 3 showed evidence of association with adiponectin levels (P=0.0009) and with T2D (P=0.005). We failed to detect an association with insulin resistance indexes. Although family-based association analysis with T2D did not reach significance, our results suggest that an at-risk haplotype of common variants located in the promoter and rare mutations in exon 3 contribute to the variation of the adipocyte-secreted adiponectin hormone level, and may be part of the genetic determinants for T2D in the French Caucasian population.

[Otosclerosis surgical techniques and results in 150 patients]

OBJECTIVES

To analyze outcome after otosclerosis surgery with stamedeotomy with blood clot sealing.

PATIENTS AND METHODS

Otosclerosis surgery was performed in 150 adult patients between 1997 and 1999 by five surgical teams (70% of the procedures were performed by senior surgeons) and followed for 18 months. Stapedotomy was carried out under general anesthesia with an intrameatal approach in 96% of the cases. Stapedotomy (n=120, 80%) was performed with a drill in 141 cases and by laser in 9 (6%). Ninety percent of the Teflon prostheses had a 0.4 mm diameter and a 4.5 mm length. The footplate opening was sealed with blood clots. Venous interposition (n=30, 20%) was performed in the event of partial or total stapedectomy which occurred in spite of an initial stapedotomy attempt.

RESULTS

The preoperative air-bone gap (ABG) was 32 +/- 10.3 dB. The gain in air conduction was 25 +/- 11.7 dB with 75% of the patients having more than 15 dB gain. The ABG was 10 +/- 5.4 dB with 73% of the patients having less than 5 dB gain. The interaural difference was 0.5 +/- 14.1 dB and the bone conduction (BC) variation was 1 +/- 7.5 dB. Functional failures were related to significant intralabyrinthine bleeding and revision procedure. The following factors had not effect on outcome: i) stapedotomy versus partial or total stapedectomy, footplate opening sealed by clots or vein, ii) diameter of the stapedotomy and/or the prosthesis, iii) surgical procedure performed by a junior surgeon.

CONCLUSION

Sealing the stapedotomy opening with blood clots appears to provide reliable and reproducible functional outcome that remains stable over time. In this study, changing from partial to total stapedectomy with vein interposition did not modify the functional outcome.

Rapid SNP allele frequency determination in genomic DNA pools by pyrosequencing

Individual genotyping of single nucleotide polymorphisms (SNPs) remains expensive, especially for linkage disequilibrium mapping strategies involving high-throughput SNP genotyping. On one hand, current methods may suit scientific and laboratory needs in regard to accuracy, reproducibility/robustness, and large-scale application. On the other hand, a cheaper and less time-consuming alternative to individual genotyping is the use of SNP allelefrequencies determined in DNA pools. We have developed an accurate and reproducible protocol for allele frequency determination using Pyrosequencing technology in large genomic DNA pools (374 individuals). The measured correlation (R2) in large DNA pools was 0.980. In the context of disease-associated SNPs studies, we compared the allele frequencies between the disease (e.g., type 2 diabetes and obesity) and control groups detected by either individual genotyping or Pyrosequencing of DNA pools. In large pools, the variation between the two methods was 1.5 +/- 0.9%. It may be concluded that the allele frequency determination protocol could reliably detect over 4% differences between populations. The method is economical in regard to amounts of DNA, PCR, and primer extension reagents required. Furthermore, it allows the rapid determination of allelefrequency differences in case/control groups for association studies and susceptibility gene discovery in complex diseases.

Genome-wide search for type 2 diabetes in Japanese affected sib-pairs confirms susceptibility genes on 3q, 15q, and 20q and identifies two new candidate Loci on 7p and 11p

The genetic background that predisposes the Japanese population to type 2 diabetes is largely unknown. Therefore, we conducted a 10-cM genome-wide scan for type 2 diabetes traits in the 359 affected individuals from 159 families, yielding 224 affected sib-pairs of Japanese origin. Nonparametric multipoint linkage analyses performed in the whole population showed one suggestive linked region on 11p13-p12 (maximum logarithm of odds score [MLS] 3.08, near Pax6) and seven potentially linked regions (MLS >1.17) at 1p36-p32, 2q34, 3q26-q28, 6p23, 7p22-p21, 15q13-q21, and 20q12-q13 (near the gene for hepatocyte nuclear factor-4alpha [HNF-4alpha]). Subset analyses according to maximal BMI and early age at diagnosis added suggestive evidence of linkage with type 2 diabetes at 7p22-p21 (MLS 3.51), 15q13-q21 (MLS 3.91), and 20q12-q13 (MLS 2.32). These results support previous indication for linkage found on chromosome 3q, 15q, and 20q in other populations and identifies two new potential loci on 7p and 11p that may confer genetic risk for type 2 diabetes in the Japanese population.

Genetic variation in the gene encoding adiponectin is associated with an increased risk of type 2 diabetes in the Japanese population

An adipocyte-derived peptide, adiponectin (also known as GBP28), is decreased in subjects with type 2 diabetes. Recent genome-wide scans have mapped a diabetes susceptibility locus to chromosome 3q27, where the adiponectin gene (APM1) is located. Herein, we present evidence of an association between frequent single nucleotide polymorphisms at positions 45 and 276 in the adiponectin gene and type 2 diabetes (P = 0.003 and P = 0.002, respectively). Subjects with the G/G genotype at position 45 or the G/G genotype at position 276 had a significantly increased risk of type 2 diabetes (odds ratio 1.70 [95% CI 1.09-2.65] and 2.16 [1.22-3.95], respectively) compared with those having the T/T genotype at positions 45 and 276, respectively. In addition, the subjects with the G/G genotype at position 276 had a higher insulin resistance index than those with the T/T genotype (1.61 +/- 0.05 vs. 1.19 +/- 0.12, P = 0.001). The G allele at position 276 was linearly associated with lower plasma adiponectin levels (G/G: 10.4 +/- 0.85 microg/ml, G/T: 13.7 +/- 0.87 microg/ml, T/T: 16.6 +/- 2.24 microg/ml, P = 0.01) in subjects with higher BMIs. Based on these findings together with the observation that adiponectin improves insulin sensitivity in animal models, we conclude that the adiponectin gene may be a susceptibility gene for type 2 diabetes.

Mutation screening of the urocortin gene: identification of new single nucleotide polymorphisms and association studies with obesity in French Caucasians

A linkage between obesity-related phenotypes and the 2p21-23 locus has been reported previously. The urocortin (UCN) gene resides at this interval, and its protein decreases appetite behavior, suggesting that UCN may be a candidate gene for susceptibility to obesity. We localized the UCN gene by radiation hybrid mapping, and the surrounding markers were genotyped in a collection of French families. Evidence for linkage was shown between the marker D2S165 and leptin levels (LOD score, 1.34; P = 0.006) and between D2S2247 and the z-score of body mass index (LOD score, 1.829; P = 0.0019). The gene was screened for SNPs in 96 obese patients. Four new variants were established. Two single nucleotide polymorphisms were located in the promoter (-535 A-->G, -286 G-->A), one in intron 1 (+31 C-->G), and one in the 3'-untranslated region (+34 C-->T). Association studies in cohorts of 722 unrelated obese and 381 control subjects and transmission disequilibrium tests, performed for the two frequent promoter polymorphisms, in 120 families (894 individuals) showed that no association was present between these variants and obesity, obesity-related phenotypes, and diabetes. Thus, our analyses of the genetic variations of the UCN gene suggest that, at least in French Caucasians, they do not represent a major cause of obesity.

Prevalence of the missense mutation Gly574Ser in the hepatocyte nuclear factor-1alpha in Africans with diabetes

BACKGROUND

Clinical presentation and natural history of diabetes are somewhat different in Black Africans compared to Caucasians. This peculiar disease course could be at least partly related to a specific genetic profile that has not been studied in this population.

METHODS

Medical backgrounds, anthropometric and biologic parameters were obtained from 69 diabetic subjects in Dakar, Senegal, in 1998. Blood anti GAD and Islet Cell Antibodies were studied, using RIA and immunofluorescence assay. The HNF-1alpha gene was sequenced searching the Gly574Ser mutation, previously described in MODY 3.

RESULTS

Among these 69 diabetic patients, 11 (16%) were found to have the G574S mutation affecting the HNF-1alpha. These 11 patients carrying the mutation were compared respectively with the 58 non carriers. Mean age (57.5 yr. +/- 11 vs 51.1 yr. +/- 15) and duration of diabetes (11.9 vs 6.7 yr), were similar in the two groups. BMI was not different in patients with the mutation (26.3 vs 23.3, p=0.06). Metabolic control (Glycosylated hemoglobin) was poor in the two groups (9.5% vs 9.2%). Chronic complications were equally found in the patients, but no mutation carrier had macroangiopathy. None of the anti GAD positive or ICA positive patients had the mutation.

CONCLUSIONS

The HNF-1alpha Gly574Ser mutation was found in 16% of cases in a 69 diabetic patients group in Senegal. Diabetes was as severe as in non carriers of mutation. This mutation has been implicated in atypical diabetes of Afro-American children. The study confirms its prevalence in Africans with diabetes.

Genetics of pathways regulating body weight in the development of obesity in humans

Although rapid globalization of the Westernized way of life is responsible for the large rise in the number of obesity cases (about 1 billion individuals are now overweight or frankly obese), obesity is a typical common multifactorial disease in that environmental and genetic factors interact, resulting in a disease state. There is strong evidence for a genetic component to human obesity: e.g., the familial clustering (the relative risk among siblings being 3-7) and the high concordance of body composition in monozygotic twins. However, the role of genetic factors in many human obesities (referred to as "common obesity" in this review) is complex, being determined by interaction of several genes (polygenic), each of which may have relatively small effects (i.e., they are "susceptibility" genes and work in combination with each other as well as with environmental factors such as nutrients, physical activity, and smoking).

Genetics of human obesity

Obesity is a multifactorial condition. Environmental risk factors related to a sedentary life-style and unlimited access to food apply constant pressure in subjects with a genetic predisposition to gain weight. The fact that genetic defects can result in human obesity has been unequivocally established over the past 3 years with the identification of the genetic defects responsible for different monogenic forms of human obesity: the leptin, leptin receptor, pro-opiomelanocortin, pro-hormone convertase-1 and melanocortin-4 receptor genes. The common forms of obesity are, however, polygenic. The examination of specific genes for involvement in the susceptibility to common obesity has not yet yielded convincing results. Approaches involving the candidate genes and the positional cloning of major obesity-linked regions (state-of-the-art future prospects) will be discussed.

Routine mutation screening of HNF-1alpha and GCK genes in MODY diagnosis: how effective are the techniques of DHPLC and direct sequencing used in combination?

AIMS/HYPOTHESIS

Mutations in the hepatocyte nuclear factor (HNF)-1alpha and glucokinase (GCK) genes are the major causes of monogenic forms of Type II (non-insulin-dependent) diabetes mellitus (Maturity-Onset Diabetes of the Young subtypes, MODY). We evaluated the effectiveness of fluorescent single-strand conformation polymorphism (F-SSCP), denaturing high-performance liquid chromatography (DHPLC) and sequencing based mutation detection in the molecular diagnosis of MODY. Our goal is to identify a rapid, efficient and cost effective mutation detection method for the molecular diagnosis of MODY and other human genetic disorders.

METHODS

We evaluated the accuracy of DHPLC in screening for MODY 2 and 3 mutations. In addition, we compared the sensitivity, specificity, cost, handling time and analysis time of fluorescent single-strand conformation polymorphism, denaturing high-performance liquid chromatography and direct sequencing screening methods.

RESULTS

Denaturing high-performance liquid chromatography is a recently developed method for mutation detection. It is cost effective, powerful and reliable and quite suitable for 22 out of the 24 fragments required for MODY 2 and 3 testing. However, exons 1 and 7 of the HNF-1alpha gene are very polymorphic and so direct sequencing is faster as well as more efficient and reliable.

CONCLUSION/INTERPRETATION

Our results suggest that combining denaturing high-performance liquid chromatography and direct sequencing is a good approach for the routine detection of HNF-1alpha and GCK mutations in MODY families. Denaturing high-performance liquid chromatography appears to be a powerful tool in genetic testing and the method could be applied to the molecular diagnosis of other human genetic diseases.

Linkage and association studies between the proopiomelanocortin (POMC) gene and obesity in caucasian families

AIMS/HYPOTHESIS

The region 2p21-23, containing the proopiomelanocortin gene (POMC), was reported to be linked to leptin concentrations in Mexican-American, French and African-American cohorts. A polyhormone peptide, POMC is expressed in brain, gut, placenta and pancreas. The POMC mutations are responsible for rare cases of early-onset obesity. Thus we examined the contribution of the POMC locus to obesity in French families.

METHODS

Single and multipoint linkage studies were done between obesity, obesity associated-phenotypes (leptin values and z-score of the body mass index) and three newly mapped markers surrounding POMC in 264 affected sib-pairs from French obese families. Mutation screening of the exons and intron/exon junctions of the POMC gene was realised by direct sequencing. Association studies were done in 379 unrelated obese patients and 370 non-obese non-diabetic subjects.

RESULTS

Linkage analysis confirmed the trend towards linkage between polymorphic markers around POMC and variations of leptin concentrations and z-score (maximum lod score at D2S2337 = 2.03). Mutation screening of the POMC gene in the French Caucasian cohort identified two previously reported polymorphisms. None of these variants was associated with obesity, diabetes or serum leptin and lipid concentrations.

CONCLUSION/INTERPRETATION

Our results indicate that mutations in the POMC gene do not contribute to the variance of obesity associated phenotypes, at least in French Caucasians. Given the replicated evidence of linkage between leptin values and the chromosome 2p21-23 region in different populations, it is likely that functional variant(s) in the POMC regulating sequences or in an unknown gene in this region explains this linkage.

The gene MAPK8IP1, encoding islet-brain-1, is a candidate for type 2 diabetes

Type 2 diabetes is a polygenic and genetically heterogeneous disease . The age of onset of the disease is usually late and environmental factors may be required to induce the complete diabetic phenotype. Susceptibility genes for diabetes have not yet been identified. Islet-brain-1 (IB1, encoded by MAPK8IP1), a novel DNA-binding transactivator of the glucose transporter GLUT2 (encoded by SLC2A2), is the homologue of the c-Jun amino-terminal kinase-interacting protein-1 (JIP-1; refs 2-5). We evaluated the role of IBi in beta-cells by expression of a MAPK8IP1 antisense RNA in a stable insulinoma beta-cell line. A 38% decrease in IB1 protein content resulted in a 49% and a 41% reduction in SLC2A2 and INS (encoding insulin) mRNA expression, respectively. In addition, we detected MAPK8IP1 transcripts and IBi protein in human pancreatic islets. These data establish MAPK8IP1 as a candidate gene for human diabetes. Sibpair analyses performed on i49 multiplex French families with type 2 diabetes excluded MAPK8IP1 as a major diabetogenic locus. We did, however, identify in one family a missense mutation located in the coding region of MAPK8IP1 (559N) that segregated with diabetes. In vitro, this mutation was associated with an inability of IB1 to prevent apoptosis induced by MAPK/ERK kinase kinase 1 (MEKK1) and a reduced ability to counteract the inhibitory action of the activated c-JUN amino-terminal kinase (JNK) pathway on INS transcriptional activity. Identification of this novel non-maturity onset diabetes of the young (MODY) form of diabetes demonstrates that IB1 is a key regulator of 3-cell function.

A pilot study evaluating ceftriaxone and penicillin G as treatment agents for neurosyphilis in human immunodeficiency virus-infected individuals

To compare intravenous (iv) ceftriaxone and penicillin G as therapy for neurosyphilis, blood and CSF were collected before and 14-26 weeks after therapy from 30 subjects infected with human immunodeficiency virus (HIV)-1 who had (1) rapid plasma reagin (RPR) test titers >/=1&rcolon;16, (2) reactive serum treponemal tests, and (3) either reactive CSF-Venereal Disease Research Laboratory (VDRL) tests or CSF abnormalities: (a) CSF WBC values >/=20/microL or (b) CSF protein values >/=50 mg/dL. At baseline, more ceftriaxone recipients had skin symptoms and signs (6 [43%] of 14 vs. 1 [6%] of 16; P=.03), and more penicillin recipients had a history of neurosyphilis (7 [44%] of 16 vs. 1 [7%] of 14; P=.04). There was no difference in the proportion of subjects in each group whose CSF measures improved. Significantly more ceftriaxone recipients had a decline in serum RPR titers (8 [80%] of 10 vs. 2 [13%] of 15; P=. 003), even after controlling for baseline RPR titer, skin symptoms and signs, or prior neurosyphilis were controlled for. Differences in the 2 groups limit comparisons between them. However, iv ceftriaxone may be an alternative to penicillin for treatment of HIV-infected patients with neurosyphilis and concomitant early syphilis.

Identification of seven novel nucleotide variants in the hepatocyte nuclear factor-1alpha (TCF1) promoter region in MODY patients

Maturity onset diabetes of the young (MODY) is a heterogeneous subtype of type II diabetes mellitus. To date, five MODY genes have been identified. Mutations in the hepatocyte nuclear factor-1alpha (HNF-1alpha) gene are associated with MODY3. In the present work, we implemented the HNF-1alpha promoter region in the screening of MODY-suspect patients and identified seven variants not detected in control subjects. The family was available for the -119delG variant, and segregration between MODY and the variant is observed. Most of these variants are located in highly conserved regions and may alter HNF-1alpha expression through binding alteration of nuclear factors or other mechanisms. We demonstrate by functional studies that the transcriptional activity of the -283A>C and -218T>C variant promoters were 30% and 70% of the wild type activity, respectively. These data suggest that HNF-1alpha promoter variants could be diabetogenic mutations, and emphasize that the accurate HNF-1alpha expression is important for the maintenance of normal pancreatic beta cell function.

Anticipation in schizophrenia and bipolar disorder controlling for an information bias

Anticipation was investigated in schizophrenia (SZ) and bipolar disorder (BP) while addressing several biases in 18 large families (154 subjects) from Eastern Québec densely affected by SZ, BP, or both over three generations. In particular, we controlled for an information bias using a measure of quality and quantity of clinical information (QOI) concerning the subjects' illness. Otherwise, spurious anticipation could have arisen because we found that QOI varied with the generations as well as with the severity of illness. Although anticipation was investigated separately for SZ and BP, both disorders were also included in one analysis that tested anticipation under the unitary hypothesis that the SZ and the BP spectrums represent a continuum of severity of the same disease. Age of onset (AOO) and five indices of severity were tested for anticipation. Two statistics were used: the difference in the mean AOO or severity between two successive generations, and the mean difference in parent-offspring pairs (POP). The study led to four main findings: 1) the choice of the statistics greatly influenced the results, POP yielding systematically greater biased estimates; 2) for SZ and BP, the evidence for anticipation with the five severity indices vanished after controlling for QOI; 3) as regards AOO a decrease of 8.6 years, p = 0.0001, and 5.3 years, p = 0.009 in AOO was found for SZ between Generations 1-2, and 2-3, respectively, despite controlling for QOI and addressing all biases; and 4) conversely for BP, anticipation with AOO may be due to censoring. Findings suggest that future anticipation studies should also control for QOI. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:61-68, 2000.

Anatomy of a homeoprotein revealed by the analysis of human MODY3 mutations

Hepatocyte nuclear factor 1alpha (HNF1alpha) is an atypical dimeric homeodomain-containing protein that is expressed in liver, intestine, stomach, kidney, and pancreas. Mutations in the HNF1alpha gene are associated with an autosomal dominant form of non-insulin-dependent diabetes mellitus called maturity-onset diabetes of the young (MODY3). More than 80 different mutations have been identified so far, many of which involve highly conserved amino acid residues among vertebrate HNF1alpha. In the present work, we investigated the molecular mechanisms by which MODY3 mutations could affect HNF1alpha function. For this purpose, we analyzed the properties of 10 mutants resulting in amino acid substitutions or protein truncation. Some mutants have a reduced protein stability, whereas others are either defective in the DNA binding or impaired in their intrinsic trans-activation potential. Three mutants, characterized by a complete loss of trans-activation, behave as dominant negatives when transfected with the wild-type protein. These data define a clear causative relationship between MODY3 mutations and functional defects in HNF1alpha trans-activation. In addition, our analysis sheds new light on the structure of a homeoprotein playing a key role in pancreatic beta cell function.

Screening for distal sensory peripheral neuropathy in HIV-infected persons in research and clinical settings

OBJECTIVE

To determine the accuracy of a screening examination for distal sensory peripheral neuropathy (DSPN) performed by nonphysician clinicians and to explore the associations between DSPN and clinical features in HIV-infected persons.

METHODS

A case-control study of a volunteer sample of 226 HIV-infected individuals was performed. An interview, focusing on risks and symptoms of DSPN, and a screening neurologic examination were performed.

RESULTS

Compared with the neurologist's examinations, the clinicians' examination was sensitive (92 to 95%) but not as specific (71 to 84%) for the diagnosis of DSPN. After excluding 27 patients with confounders, 42 of 199 patients (21%) had DSPN. This was associated significantly with neurotoxic nucleoside antiretroviral use and with more advanced HIV disease. Of the 42 patients with DSPN, 30 (71%) had no neuropathy symptoms.

CONCLUSIONS

A brief examination performed by trained nonphysician clinicians can be used to screen for DSPN in HIV-infected persons. Asymptomatic DSPN is common in these individuals.

Missense mutations in the pancreatic islet beta cell inwardly rectifying K+ channel gene (KIR6.2/BIR): a meta-analysis suggests a role in the polygenic basis of Type II diabetes mellitus in Caucasians

The K+ inwardly rectifier channel (KIR) is one of the two sub-units of the pancreatic islet ATP-sensitive potassium channel complex (I(KATP)), which has a key role in glucose-stimulated insulin secretion and thus is a potential candidate for a genetic defect in Type II (non-insulin-dependent) diabetes mellitus. We did a molecular screening of the KIR6.2 gene by single strand conformational polymorphism (SSCP) and direct sequencing in 72 French Caucasian Type II diabetic families. We identified three nucleotide substitutions resulting in three amino acid changes (E23K, L270V and 1337V), that have also been identified in other Caucasian Type II diabetic subjects. These variants were genotyped in French cohorts of 191 unrelated Type II diabetic probands and 119 normoglycaemic control subjects and association studies were done. The genotype frequencies of the L270V and 1337V variants were not very different between Type II diabetic subjects and control groups. In contrast, analysis of the E23K variant showed that the KK homozygocity was more frequent in Type II diabetic than in control subjects (27 vs 14%, p = 0.015). Analyses in a recessive model (KK vs EK/EE) tended to show a stronger association of the K allele with diabetes (p = 0.0097, corrected p-value for multiple testing < 0.02). The data for the E23K variant obtained here and those obtained from three other Caucasian groups studied so far were combined and investigated by meta-analysis. Overall, the E23K variant was found to be significantly associated with Type II diabetes (0.001 < or = p < or = .00106, corrected p-values for multiple testing p < or = 0.01). This study shows that KIR6.2 polymorphisms are frequently associated with Type II diabetes in French Caucasians. Furthermore, a meta-analysis combining different Caucasian groups suggests an significant role of KIR6.2 in the polygenic context of Type II diabetes.

Mutation screening in 18 Caucasian families suggest the existence of other MODY genes

Maturity-onset diabetes of the young (MODY) is a heterogeneous subtype of non-insulin-dependent diabetes mellitus characterised by early onset, autosomal dominant inheritance and a primary defect in insulin secretion. To date five MODY genes have been identified: hepatocyte nuclear factor-4 alpha (HNF-4alpha/MODY1/TCF14) on chromosome 20q, glucokinase (GCK/MODY2) on chromosome 7p, hepatocyte nuclear factor-1 alpha (HNF-1alpha/MODY3/TCF1) on chromosome 12q, insulin promoter factor-1 (IPF1/MODY4) on chromosome 13q and hepatocyte nuclear factor-1 beta (HNF-1beta/MODY5/TCF2) on chromosome 17cen-q. We have screened the HNF-4alpha, HNF-1alpha and HNF-1beta genes in members of 18 MODY kindreds who tested negative for glucokinase mutations. Five missense (G31D, R159W, A161T, R200W, R271W), one substitution at the splice donor site of intron 5 (IVS5nt + 2T-->A) and one deletion mutation (P379fsdelT) were found in the HNF-1alpha gene, but no MODY-associated mutations were found in the HNF-4alpha and HNF-1beta genes. Of 67 French MODY families that we have now studied, 42 (63%) have mutations in the glucokinase gene, 14 (21%) have mutations in the HNF-1alpha gene, and 11 (16%) have no mutations in the HNF-4alpha, IPF1 and HNF-1beta genes. Eleven families do not have mutations in the five known MODY genes suggesting that there is at least one additional locus that can cause MODY.

A missense mutation in hepatocyte nuclear factor-4 alpha, resulting in a reduced transactivation activity, in human late-onset non-insulin-dependent diabetes mellitus

Non-insulin-dependent diabetes mellitus (NIDDM) is a heterogeneous disorder characterized by hyperglycemia resulting from defects in insulin secretion and action. Recent studies have found mutations in the hepatocyte nuclear factor-4 alpha gene (HNF-4alpha) in families with maturity-onset diabetes of the young (MODY), an autosomal dominant form of diabetes characterized by early age at onset and a defect in glucose-stimulated insulin secretion. During the course of our search for susceptibility genes contributing to the more common late-onset NIDDM forms, we observed nominal evidence for linkage between NIDDM and markers in the region of the HNF-4alpha/MODY1 locus in a subset of French families with NIDDM diagnosed before 45 yr of age. Thus, we screened these families for mutations in the HNF-4alpha gene. We found a missense mutation, resulting in a valine-to-isoleucine substitution at codon 393 in a single family. This mutation cosegregated with diabetes and impaired insulin secretion, and was not present in 119 control subjects. Expression studies showed that this conservative substitution is associated with a marked reduction of transactivation activity, a result consistent with this mutation contributing to the insulin secretory defect observed in this family.

[Intra-labyrinthine schwannomas: a report of two cases]

Intralabyrinthine schwannomas are rare tumors of vestibule, cochlea, semicircular canals, or some combination of these three. In the past, they have been found at autopsy or as incidental finding at surgery. Since the advent of magnetic resonance imaging (MRI) with intravenous gadolinium contrast, the preoperative diagnosis is possible. We report two cases of intralabyrinthine schwannoma: one case of intralabyrinthine schwannoma extended into the internal auditory canal (IAC), a second case of tumor restricted to the vestibule. No characteristic clinical presentation of this tumor is reported in the literature. In patients with vestibular weakness (vertigo and no response of caloric testing), MRI with gadolinium contrast can make the diagnosis of intravestibular tumor. In patients with the more common IAC acoustic neuromas, MRI can demonstrate extension of tumor into the labyrinth; diagnosing this extension preoperatively is important to plan surgical treatment.