Mutation update and uncommon phenotypes in a French cohort of 96 patients with WFS1-related disorders.

WFS1 mutations are responsible for Wolfram syndrome (WS) characterized by juvenile-onset diabetes mellitus and optic atrophy, and for low-frequency sensorineural hearing loss (LFSNHL). Our aim was to analyze the French cohort of 96 patients with WFS1-related disorders in order (i) to update clinical and molecular data with 37 novel affected individuals, (ii) to describe uncommon phenotypes and, (iii) to precise the frequency of large-scale rearrangements in WFS1. We performed quantitative polymerase chain reaction (PCR) in 13 patients, carrying only one heterozygous variant, to identify large-scale rearrangements in WFS1. Among the 37 novel patients, 15 carried 15 novel deleterious putative mutations, including one large deletion of 17,444 base pairs. The analysis of the cohort revealed unexpected phenotypes including (i) late-onset symptoms in 13.8% of patients with a probable autosomal recessive transmission; (ii) two siblings with recessive optic atrophy without diabetes mellitus and, (iii) six patients from four families with dominantly-inherited deafness and optic atrophy. We highlight the expanding spectrum of WFS1-related disorders and we show that, even if large deletions are rare events, they have to be searched in patients with classical WS carrying only one WFS1 mutation after sequencing.

Autoimmune disorders and quadrivalent human papillomavirus vaccination of young female subjects.

OBJECTIVES: The aim of this study was to investigate whether the quadrivalent human papillomavirus (HPV) vaccine Gardasil is associated with a change in the risk of autoimmune disorders (ADs) in young female subjects. DESIGN: Systematic case-control study of incident ADs associated with quadrivalent HPV vaccination in young women across France. PARTICIPANTS AND SETTING: A total of 113 specialised centres recruited (from December 2007 to April 2011) females aged 14-26 years with incident cases of six types of ADs: idiopathic thrombocytopenic purpura (ITP), central demyelination/multiple sclerosis (MS), Guillain-Barré syndrome, connective tissue disorders (systemic lupus erythematosus, rheumatoid arthritis/juvenile arthritis), type 1 diabetes mellitus and autoimmune thyroiditis. Control subjects matched to cases were recruited from general practice. ANALYSIS: Multivariate conditional logistic regression analysis; factors included age, geographical origin, smoking, alcohol consumption, use of oral contraceptive(s) or vaccine(s) other than Gardasil received within 24 months before the index date and personal/family history of ADs. RESULTS: Overall, 211 definite cases of ADs were matched to 875 controls. The adjusted odds ratio (OR) for any quadrivalent HPV vaccine use was 0.9 [95% confidence interval (CI) 0.5-1.5]. The individual ORs were 1.0 (95% CI 0.4-2.6) for ITP, 0.3 (95% CI 0.1-0.9) for MS, 0.8 (95% CI 0.3-2.4) for connective disorders and 1.2 (95% CI 0.4-3.6) for type 1 diabetes. No exposure to HPV vaccine was observed in cases with either Guillain-Barré syndrome or thyroiditis. CONCLUSIONS: No evidence of an increase in the risk of the studied ADs was observable following vaccination with Gardasil within the time periods studied. There was insufficient statistical power to allow conclusions to be drawn regarding individual ADs.

EIF2AK3, encoding translation initiation factor 2-alpha kinase 3, is mutated in patients with Wolcott-Rallison syndrome.

Wolcott-Rallison syndrome (WRS) is a rare, autosomal recessive disorder characterized by permanent neonatal or early infancy insulin-dependent diabetes. Epiphyseal dysplasia, osteoporosis and growth retardation occur at a later age. Other frequent multisystemic manifestations include hepatic and renal dysfunction, mental retardation and cardiovascular abnormalities. On the basis of two consanguineous families, we mapped WRS to a region of less than 3 cM on chromosome 2p12, with maximal evidence of linkage and homozygosity at 4 microsatellite markers within an interval of approximately 1 cM. The gene encoding the eukaryotic translation initiation factor 2-alpha kinase 3 (EIF2AK3) resides in this interval; thus we explored it as a candidate. We identified distinct mutations of EIF2AK3 that segregated with the disorder in each of the families. The first mutation produces a truncated protein in which the entire catalytic domain is missing. The other changes an amino acid, located in the catalytic domain of the protein, that is highly conserved among kinases from the same subfamily. Our results provide evidence for the role of EIF2AK3 in WRS. The identification of this gene may provide insight into the understanding of the more common forms of diabetes and other pathologic manifestations of WRS.

The putative forkhead transcription factor FOXL2 is mutated in blepharophimosis/ptosis/epicanthus inversus syndrome.

In type I blepharophimosis/ptosis/epicanthus inversus syndrome (BPES), eyelid abnormalities are associated with ovarian failure. Type II BPES shows only the eyelid defects, but both types map to chromosome 3q23. We have positionally cloned a novel, putative winged helix/forkhead transcription factor gene, FOXL2, that is mutated to produce truncated proteins in type I families and larger proteins in type II. Consistent with an involvement in those tissues, FOXL2 is selectively expressed in the mesenchyme of developing mouse eyelids and in adult ovarian follicles; in adult humans, it appears predominantly in the ovary. FOXL2 represents a candidate gene for the polled/intersex syndrome XX sex-reversal goat.

Mutant WD-repeat protein in triple-A syndrome.

Triple-A syndrome (MIM 231550; also known as Allgrove syndrome) is an autosomal recessive disorder characterized by adrenocorticotropin hormone (ACTH)-resistant adrenal insufficiency, achalasia of the oesophageal cardia and alacrima. Whereas several lines of evidence indicate that triple-A syndrome results from the abnormal development of the autonomic nervous system, late-onset progressive neurological symptoms (including cerebellar ataxia, peripheral neuropathy and mild dementia) suggest that the central nervous system may be involved in the disease as well. Using fine-mapping based on linkage disequilibrium in North African inbred families, we identified a short ancestral haplotype on chromosome 12q13 (<1 cM), sequenced a BAC contig encompassing the triple-A minimal region and identified a novel gene (AAAS) encoding a protein of 547 amino acids that is mutant in affected individuals. We found five homozygous truncating mutations in unrelated patients and ascribed the founder effect in North African families to a single splice-donor site mutation that occurred more than 2,400 years ago. The predicted product of AAAS, ALADIN (for alacrima-achalasia-adrenal insufficiency neurologic disorder), belongs to the WD-repeat family of regulatory proteins, indicating a new disease mechanism involved in triple-A syndrome. The expression of the gene in both neuroendocrine and cerebral structures points to a role in the normal development of the peripheral and central nervous systems.

Hybrid closed Loop improved glucose control compared to sensor-augmented pumps in outpatients with type 1 diabetes in real-life conditions with telehealth monitoring.

OBJECTIVES: The study aims at evaluating glucose metrics and HbA1C values after pump initiation in outpatient settings. RESEARCH DESIGN AND METHODS: This single center observational study enrolled 121 subjects with type 1 diabetes between September 2020 and May 2021 initiating sensor-augmented pump therapy with stand-alone CGM (n = 26) or pump users who only changed their device (n = 51), with predictive low glucose management (n = 8) or with Hybrid Closed Loop using Medtronic 780G (n = 36) systems. Changes in HbA1C levels and glucose metrics were analyzed after 3 months. All subjects received diabetes and carbohydrate-counting education if needed at time of initiation and were proposed a telehealth monitoring by a diabetic nurse educator. RESULTS: There was no episodes of severe hypoglycemia or diabetic ketoacidosis nor serious pump-related adverse events despite outpatient model of care. While only 18/121 (14.8%) participants reached initially the recommended HbA1C levels, 23/85 (27%) in the conventional group and 33/36 (91%) subjects in the Hybrid Closed Loop group reached target levels after 3 months of follow-up. Time in target range 3.9-10 mmol/L (70-180 mg/dl) also improved and was optimal with closed loop with 30/36 (83%) subjects with time in range above 70%. CONCLUSIONS: Initiation of insulin pump therapy for outpatients is safe with a dedicated facility. Telehealth monitoring after outpatient initiation provides tools for improvement in glucose control with an insulin pump. Outpatient pump initiation is compatible with Hybrid Closed Loop systems which provide the largest improvements in glucose control.

Specific gene expression signature associated with development of autoimmune type-I diabetes using whole-blood microarray analysis.

Understanding the pathogenesis of type-I diabetes (T1D) is hindered in humans by the long autoimmune process occurring before clinical onset and by the difficulty to study the pancreas directly. Alternatively, exploring body fluids and particularly peripheral blood can provide some insights. Indeed, circulating cells can function as 'sentinels', with subtle changes in gene expression occurring in association with disease. Therefore, we investigated the gene expression profiles of circulating blood cells using Affymetrix microarrays. Whole-blood samples from 20 first-degree relatives of T1D children with autoimmune diabetes-related antibodies, 19 children immediately after the onset of clinical T1D and 20 age- and sex-matched healthy controls were collected in PAXgene tubes. A global gene expression analysis with MDS approach allowed the discrimination of pre-diabetic subjects, diabetic patients and healthy controls. Univariate statistical analysis highlighted 107 distinct genes differently expressed between these three groups. Two major gene expression profiles were characterized, including type-I IFN-regulated genes and genes associated with biosynthesis and oxidative phosphorylation. Our results showed the presence of early functional modifications associated with T1D, which could help to understand the disease and suggest possible avenues for therapeutic interventions.

GNAS mutated thyroid carcinoma in a patient with Mc Cune Albright syndrome.

Mc Cune-Albright syndrome (MAS) is a rare disorder defined by the triad of polyostotic fibrous dysplasia, "café au lait" skin hyperpigmentation and hyperfunctioning endocrinopathies, such as precocious puberty. MAS is caused by an activating post zygotic somatic mutation of GNAS gene, coding for the alpha-subunit of the stimulatory G protein (Gsalpha). In endocrine tissues, this mutation results in overproduction of hormones and endocrine cell hyperfunction and proliferation. Whereas the association of hyperthyroidism and thyroid adenomas is well known in MAS, the relation with thyroid carcinoma has rarely been observed. We report the occurrence of a thyroid carcinoma in an 18-years old woman with MAS, revealed by subclinical hyperthyroidism detected during her systematic annual follow-up. Ultrasound and thyroid scintigraphy revealed the presence of a nodule in the right lobe. Pathology on hemithyroidectomy revealed an unexpected thyroid follicular carcinoma. Neoplastic thyroid cells harbored the GNAS R201C activating mutation. This observation suggests that MAS may predispose patients to thyroid carcinomas and supports the importance of thyroid assessment by physical examination, hormonal blood test and ultrasound, in the follow-up of patients with MAS. Because ultrasound diagnostic is challenging in MAS, needle puncture of palpable nodules should be advised.

[New approaches for the treatment of metabolic myopathies]. / Nouveautés dans le traitement des myopathies métaboliques.

Metabolic myopathies are inborn errors of intermediate muscle metabolism, presenting either by exercise intolerance, or by progressive muscle weakness. Growing knowledge concerning the pathophysiology of these rare disorders, and the development of new technologies, opens new avenues for the treatment of this group of myopathies. Recent studies showed improvement in exercise capacity after regular aerobic exercise training in patients with McArdle's disease and mitochondrial myopathies. In late-onset Pompe disease enzyme replacement therapy trials with recombinant acid alpha-glucosidase (Myozyme) are currently in progress, the first trials conducted in childhood onset Pompe disease having previously shown a clear improvement in life expectancy and cardiac function. The demonstration that fibrates can induce correction of carnitine palmitoyl-transferase II deficiency in patients cells, lead to the development of an open-labelled therapeutic trial with bezafibrate in patients with CPTII deficiency, which is actually ongoing.

Reinforced follow-up for children and adolescents with type 1 diabetes and inadequate glycaemic control: a randomized controlled trial intervention via the local pharmacist and telecare.

AIM: To evaluate the effectiveness and feasibility of reinforced follow-up via telecare mediated by the local pharmacist in contact with the hospital team to improve glycaemic control in children and adolescents with type 1 diabetes (DT1). METHODS: One hundred patients, aged 8 to 17 years, with a history of DT1 of more than 1 year, with HbA(1c) >=8%, were randomly assigned to either the "reinforced follow-up" group (RFG) or the "usual follow-up" group (UFG). The intervention consisted in downloading and then printing data stored in a glucometer every two weeks, by the local pharmacist. Printouts were faxed to the hospital team which then communicated adapted instructions for better glycemic control directly to the family. RESULTS: Fifty patients were assigned to each group. The two groups were comparable at the beginning. 71 children had a doctor's visit at 6 +/- 1 months (36 in RFG and 35 in UFG). At this date, there was no significant difference between the average HbA(1c) levels of the two groups (9.12 +/- 1.46 in RFG versus 9.27 +/- 1.20 in UFG). We had various difficulties setting up and gaining compliance with the intervention procedure, which explains why only 33 children in the RFG transmitted at least one fax. CONCLUSION: At this stage, the reinforced follow-up has not proved to be superior to the usual follow-up. However, it would be possible to make numerous improvements in order to make the former more feasible and probably more efficient.

[Adrenal hypoplasia congenita: four new cases in children]. / Hypoplasie congénitale des surrénales : à propos de quatre observations.

Adrenal hypoplasia congenita (AHC) is an extremely uncommon disease of early onset. This condition can be lethal in the absence of adapted treatment. Some of these diseases are related to changes in the gene DAX1 that encodes a member of the superfamily of hormone nuclear receptors. It is a transcriptional repressor that is central in the morphogenesis of the adrenals and the gonadic differentiation. Here we report on four cases of X- linked AHC. In the first two familial cases, mutations were identified and mothers were heterozygotes. Abnormally low levels of estriol were evidenced during the pregnancy leading to an early diagnosis and adapted care of the affected male neonates. These children are doing well with a 21-and 20 months follow-up with hormone replacement at the present time. The two last cases corresponded to a contiguous gene syndrome associating AHC to glycerol-kinase deficiency that was revealed respectively at six days and seven years of age by acute adrenal insufficiency.

21-Hydroxylase deficiency: an exemplary model of the contribution of molecular biology in the understanding and management of the disease.

Congenital adrenal hyperplasia (CAH) is a family of autosomal recessive disorders caused by mutations in genes encoding the enzymes involved in one of the various steps of adrenal steroid synthesis. Steroid 21-hydroxylase deficiency (21-OHD) is responsible for over 95% of the 5 forms of CAH, and results due to enzymatic defect owing to mutation in the CYP21 gene. The disease has two major clinical presentations. The "classical" form is severe, and divided into a salt wasting (SW) and simple virilizing (SV) subgroups. In both, affected female fetuses undergo virilization of the external genitalia prenatally and present at birth with sexual ambiguity. In addition, in both sexes infants with SW CAH are at risk of life-threatening adrenal crisis without treatment. This is why it is so important to make a diagnosis and to counsel the families. The diagnosis is easy by measuring the plasma levels of 17-hydroxyprogesterone (17-OHP) in antenatal (amniotic fluid), or perinatal samples (peripheral blood). Confirmation by molecular genetic analysis is advised. The second form of 21-OHD is called "non classical" because the presentation is much less severe and the onset of clinical expression occurs long after birth, often in the peripubertal period, as non-specific symptoms of hyperandrogeny. The unambiguous diagnosis of the latter requires a simple short ACTH test, with the measurement of 17-OHP at 60 min. In both forms, the mutations on the gene CYP21 responsible for the disease are now well known and can be identified by molecular biology techniques. There is a good correlation between phenotypes and genotypes, due to variable amount of the 21-hydroxylase-enzyme activity left (null to 50-60%). SW, SV and NC forms are associated with distinct mutations or combination of mutations. Nowadays, by combining hormonal and molecular tests, it is possible to predict the clinical form of the disease in a given family in the context of a prenatal diagnosis, which can lead to a prenatal treatment. Therefore, 21-OHD genotyping also appears essential for a new approach of genetic counseling, prediction of clinical form after postnatal screening and to define the post-ACTH 17-OHP values indicating the cut-off lines between NC, heterozygote and normal subjects.

[Ketoacidosis at time of diagnosis of type 1 diabetes in children and adolescents: effect of a national prevention campaign]. / Effet à un an de la campagne nationale de prévention de l'acidocétose au moment du diagnostic de diabète de type 1 chez l'enfant et l'adolescent.

The aim of the study was to evaluate, after the first year of a national information campaign, the effect on the frequency and severity of diabetic ketoacidosis (DKA) at diagnosis of type 1 diabetes (T1D) in children and adolescents in France. The following data were collected during a 2-year period in people younger than 15 years of age at diagnosis of T1D, in 146 pediatric centers: age, sex, duration of symptoms, patient's previous care, clinical and biological signs, and family history of T1D. DKA was defined as pH<7.30 or bicarbonate<15mmol/L, severe DKA as pH<7.10 or bicarbonate <5mmol/L. During the 2nd year, an information campaign targeting health professionals and families was launched with the objective of reducing the time to diagnosis. Data were compared between the year before the campaign (year 0) and the first year of the campaign (year 1). The number of new cases of T1D was 1299 for year 0 and 1247 for year 1. Between year 0 and year 1, the rate of DKA decreased from 43.9% to 40.5% (P=0.08), exclusively due to the decrease of severe DKA from 14.8 to 11.4% (P=0.01). In the 0- to 5-year-old and 5- to 10-year-old age groups, the relative decrease in the rate of DKA was 13% and 15%, and 23% and 41% for severe DKA, respectively. In patients referred to the hospital by a pediatrician or who came at the family's initiative, the decrease was 34% and 7%, and 39% and 32% for severe DKA, respectively. No change was observed in the 10- to 15-year-old group or in those children who were referred by a general practitioner. In multivariate analyses, a higher DKA rate was associated with the young age of the child (<5 years), being hospitalized at the parents' initiative rather than being referred by a doctor, and the absence of a family history of T1D. A higher rate of severe DKA was associated with these last two factors but not with the child's age. The frequency of DKA at diagnosis of type 1 diabetes remains high in children and adolescents, but the first year of an information campaign decreased it. The results have also helped better define the strategy and targets of the continuing prevention campaign, to more efficiently reduce the morbidity and mortality of T1D at diagnosis in children and adolescents in France.

Elevated ratio of acylated to unacylated ghrelin in children and young adults with Prader-Willi syndrome.

Prader-Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. Hyperghrelinemia may be involved in the underlying mechanisms of the switch. The purpose of this study is to evaluate acylated ghrelin (AG) and unacylated ghrelin (UAG) levels in PWS and investigate their associations with hyperphagia. This is a cross-sectional clinical study conducted in three PWS expert centers in the Netherlands and France. Levels of AG and UAG and the AG/UAG ratio were determined in 138 patients with PWS (0.2-29.4 years) and compared with 50 age-matched obese subjects (4.3-16.9 years) and 39 healthy controls (0.8-28.6 years). AEBSF was used to inhibit deacylation of AG. As a group, PWS patients had higher AG but similar UAG levels as healthy controls (AG 129.1 vs 82.4 pg/ml, p = 0.016; UAG 135.3 vs 157.3 pg/ml, resp.), resulting in a significantly higher AG/UAG ratio (1.00 vs 0.61, p = 0.001, resp.). Obese subjects had significantly lower AG and UAG levels than PWS and controls (40.3 and 35.3 pg/ml, resp.), but also a high AG/UAG ratio (1.16). The reason for the higher AG/UAG ratio in PWS and obese was, however, completely different, as PWS had a high AG and obese a very low UAG. PWS patients without weight gain or hyperphagia had a similar AG/UAG ratio as age-matched controls, in contrast to those with weight gain and/or hyperphagia who had an elevated AG/UAG ratio. The switch to excessive weight gain in PWS seems to coincide with an increase in the AG/UAG ratio, even prior to the start of hyperphagia.

Identification of a large-scale mitochondrial deoxyribonucleic acid deletion in endocrinopathies and deafness: report of two unrelated cases with diabetes mellitus and adrenal insufficiency, respectively.

In recent years, a broad variety of chronic diseases have been related to different mitochondrial DNA (mtDNA) rearrangements. We have investigated two 16-yr-old unrelated girls with unexplained endocrine disorders for a mtDNA mutation. One initially presented with an adrenal crisis at the age of 4 yr. Complete adrenal insufficiency for nearly 15 yr was the main clinical manifestation, along with insiduous growth retardation and sensorineural hearing loss since age 6. The other girl presented with ketoacidosis at the age of 15 yr. She exhibited incomplete deafness since age 6 and poor growth. In both patients, brain magnetic resonance imaging abnormalities and raised cerebrospinal fluid protein concentration indicated mild leucodystrophy. Biopsy of skeletal muscle showed a mitochondrial dysfunction; molecular analysis using a PCR screening procedure revealed a 7.4 kb deletion of the mtDNA in skeletal muscle but not in leucocytes. Direct sequence analysis of the junctional regions showed that the deletion spanned 7.436 kb (nucleotide 8649 to nucleotide 16084). The relative amount of deleted mtDNA estimated by Southern blot analysis was 25 and 15%, respectively. No deletion was present in leukocytes obtained from the asymptomatic mothers. The presence of the same mutation in different patients with various endocrine conditions supports the view that the 7.4 kb mtDNA deletion should be considered as one of the candidate causes for phenotypically uncommon cases of endocrinopathies, specially in children with deafness. This is the first report of a mitochondrial disease with primary adrenocortical insufficiency as the clinical onset.

Evaluation of gonadal function in 107 intersex patients by means of serum antimüllerian hormone measurement.

Fetal male sexual differentiation is driven by two testicular hormones: testosterone (synthesized by interstitial Leydig cells) and antimüllerian hormone (AMH; produced by Sertoli cells present in the seminiferous tubules). Intersex states result either from gonadal dysgenesis, in which both Leydig and Sertoli cell populations are affected, or from impaired secretion or action of either testosterone or AMH. Until now, only Leydig cell function has been assessed in children with ambiguous genitalia, by means of testosterone assay. To determine whether serum AMH would help in the diagnosis of intersex conditions, we assayed serum AMH levels in 107 patients with ambiguous genitalia of various etiologies. In XY patients, AMH was low when the intersex condition was caused by abnormal testicular determination (including pure and partial gonadal dysgenesis) but was normal or elevated in patients with impaired testosterone secretion, whereas serum testosterone was low in both groups. AMH was also elevated during the first year of life and at puberty in intersex states caused by androgen insensitivity. In 46,XX patients with a normal male phenotype or ambiguous genitalia, in whom the diagnosis of female pseudohermaphroditism had been excluded, serum AMH levels higher than 75 pmol/L were indicative of the presence of testicular tissue and correlated with the mass of functional testicular parenchyma. In conclusion, serum AMH determination is a powerful tool to assess Sertoli cell function in children with intersex states, and it helps to distinguish between defects of male sexual differentiation caused by abnormal testicular determination and those resulting from isolated impairment of testosterone secretion or action.

Juvenile and adult-onset acid maltase deficiency in France: genotype-phenotype correlation.

OBJECTIVE: To characterize the phenotypes of patients with juvenile and adult-onset acid maltase deficiency (AMD) in the French population and correlate them with genetic defects. BACKGROUND: AMD is an autosomal recessive disorder caused by the absence of the enzyme acid a-glucosidase (GAA). Patients are generally compound heterozygotes for various mutations in the GAA gene. The most common mutant allele is a -13T to G transversion in intron 1. METHODS: The authors performed a clinical, biochemical, and genetic study on 21 unrelated patients with juvenile and adult-onset AMD. RESULTS: Although onset of progressive muscle weakness occurred during adulthood in all cases but one, presence of mild, nonprogressive muscular symptoms appearing during childhood was detected in 16 patients. Eighteen patients had a similar clinical pattern with pelvic girdle muscle weakness predominating in glutei and thigh adductors. Restrictive respiratory insufficiency with vital capacity less than 60% was noted in eight patients, and respiratory failure was the first manifestation in two cases. All patients but one were compound heterozygotes, and 17 carried the IVS1 (-13T ---> G) transversion (one patient was homozygous for this mutation). The two mutated alleles were identified in 10 cases, with 13 different mutations detected in the GAA gene. There was no clear correlation between the type of mutation and phenotype. CONCLUSIONS: This study shows a high genetic heterogeneity of juvenile and adult AMD in the French population. The absence of genotype-phenotype correlation suggests a complex physiopathology that requires further investigations.

Combination of autoantibody markers and risk for development of type 1 diabetes: results from a large french cohort of family members.

BACKGROUND: The aims of the study were to characterize the relatives at high risk of progression to diabetes and to determine whether rate of progression to diabetes varied according to age, specific combination of antibodies and genetic markers of susceptibility. METHODS: Family members of type 1 diabetic patients were examined through a large medical network for the presence of specific antibodies to beta cell constituents and high risk DQB1 alleles. Antibodies to insulin, GAD and IA-2 as well as ICA were examined in 4,044 family members recruited in a large prospective family study in the Rhone-Alpes region (the GRADI study). Among them, 3,951 non diabetic first degree relatives have been tested on a median of 2.2 occasions and were followed for up to 16 years. RESULTS: Presence of antibodies to GAD (3.6%), IA-2 (4.9%), insulin (2.2%) and ICA at titers equal or above 20JDF units (1.1%) were noticed at the first determination and prevalence increased among ICA positive relatives versus ICA negative relatives. All combinations of markers resulted in specificities above 90%. The positive predictive value of antibodies was dependent on the number of positive antibodies. Combination of antibodies to GAD and IA-2 or GAD and IAA had higher predictive values and sensitivities than ICA titers above 20 JDF units. Additional positivity of IAA increased the predictive value but reduced the sensitivity of the screening procedure. Using a combi GAD/IA-2 assay increased the sensitivity of the screening up to 87.8% but reduced the predictive value to 13.8%. CONCLUSIONS: These data confirm in a large French cohort of first degree relatives of type 1 diabetic patients that combinations of antibodies to beta cell constituents can replace ICA in the first screening procedure. We report that combi GAD/IA-2 assay is well suited for screening purposes. However, time to diabetes in antibody positive relatives appears to be more heterogeneous to what has been described. The importance of genetic markers needs further evaluation.

High-risk genotype for type 1 diabetes: a new simple microtiter plate-based ELOSA assay.

The main contribution to genetic susceptibility for type 1 diabetes (T1D) is conferred by the HLA class II genes, with a major involvement of the DQB1*02 and 0302 alleles. The aim of our study was to develop a simple and rapid method suitable for identifying individuals with an HLA-associated T1D risk using whole blood as a source of DNA and reverse hybridization on microtiter plates (ELOSA). DNA was extracted from whole blood using various extraction methods. The PCR-amplified second exon of the DQB1 gene was hybridized at 37 degrees C for 1 hr to a set of 11 capture probes immobilized on a microtiter plate (eight-well strip per test) and corresponding to T1D susceptibility (S), protection (P), or neutral (N) alleles. Colorimetric analysis was then performed using specific oligonucleotides coupled to horseradish peroxidase and OrthoPhenyl Peroxidase (OPD) substrate. DNA samples corresponding to French (Rhône-Alpes area) T1D patients (n = 128) have been genotyped with the HLA-T1D prototype. A strong correlation is observed between susceptible genotypes and the disease, because 92.2% of the T1D individuals screened have at least one susceptible allele (DQB1*02 or *0302), thereby strengthening interest in analyzing DQB1 alleles as HLA-linked T1D markers in our Rhône-Alpes area population. Interestingly, clear T1D-associated genotyping results have been observed when using DNA samples extracted from dried blood spots, making it possible to envisage such genotyping in geographically dispersed affected families, for large-scale newborn screening, and for the inclusion of high-risk patients in clinical trials aimed at preventing the disease.