Thyroid hormone resistance from newborns to adults: a Spanish experience.

OBJECTIVE: Thyroid hormone resistance (RTH ß) is a rare genetic disorder characterized by an altered response of target tissue to the action of thyroid hormone. Few studies on RTH ß have been carried out in southern European populations. We aimed to describe the clinical and genetic characteristics at the time of diagnosis in a Spanish cohort of patients with genetically confirmed RTH ß, with ages ranging from newborns to adults. METHODS: Retrospective multicenter study of 28 patients who were genetically confirmed as RTH ß. Clinical and biochemical data were collected from the reference centers, and the studied variables included age, sex, anthropometric data, clinical characteristics and biochemical results. In the Basque country, a simultaneous analysis of TSH and T4 is carried out in the program for the screening of inborn errors of metabolism. A molecular analysis of the thyroid hormone beta (THRB) gene was performed. RESULTS: The total cohort included 20 adults and eight pediatric patients (six newborns). Of the total, 5 (17.8%) were diagnosed by clinical characteristics (goiter, hypertension or tachycardia), 13 (46.4%) were analyzed in the context of a family study and 10 (35.7%) were diagnosed after obtaining an altered fT4 and/or TSH level in a biochemical analysis performed due to clinical symptoms unrelated to RTH ß. Four of the newborns included in the series were diagnosed by the result of neonatal screening, which allows us to estimate a minimum local incidence of RTH ß of 1/18,750 live newborns. The genetic analysis showed the presence of 12 different heterozygous mutations in the THRB gene. CONCLUSIONS: We report the clinical and genetic characteristics of a Spanish RTH ß cohort, from neonates to adults. We also describe one novel mutation in the THRB gene as the cause of the disease. The simultaneous analysis of TSH and T4 carried out in the program for the screening of inborn errors of metabolism facilitates the early diagnosis of RTH ß in newborns and has allowed us to estimate a minimum local incidence of RTH of 1/18,750 live newborns.

Prevalence of diabetes mellitus and impaired glucose metabolism in the adult population of the Basque Country, Spain.

AIMS: To assess the prevalence of diabetes mellitus and impaired glucose metabolism in the Basque Country and their relationship with cardiovascular risk factors. METHODS: A population-based, cross-sectional, cluster sampling design study was carried out in an adult (≥18 years) Basque population. A total of 847 participants completed a questionnaire on personal and family medical history and lifestyle. Anthropometric variables and blood pressure were measured and biochemical analysis and an oral glucose tolerance test (75 g) were also performed. RESULTS: The total prevalence of diabetes was 10.6% (95% CI 8.65-12.95). Among them 6.3% (95% CI 4.79-8.22) had previously been diagnosed and 4.3% (95% CI 3.04-5.92) were not aware that they had diabetes. Impaired glucose tolerance was present in 7.2% (95% CI 5.53-9.15) and impaired fasting glucose in 3.8% (95% CI 2.64-5.37) of the population. In total, 21.6% of the population had some type of glucose metabolism disturbance, with a higher rate among men (28.3 vs 16.3%; P<0.001) and with the rate increasing with age. Risk factors independently associated with the development of diabetes were: male sex [odds ratio 4.58 (95% CI 2.34-8.97)]; abdominal obesity [odds ratio 2.80 (95% CI 1.47-5.36)]; high triglyceride levels [odds ratio 2.46 (95% CI 1.26-4.81)]; hypertension [odds ratio 2.40 (95% CI 1.16-4.96)]; family history of diabetes [odds ratio 2.30 (95% CI 1.25-4.24)]; high LDL cholesterol levels [odds ratio 1.83 (95% CI 1.01-3.31)] and older age [odds ratio 1.08 (95% CI 1.05-1.10)]. CONCLUSIONS: The prevalence of diabetes in the Basque Country was lower than in Spain and was independently associated with family history of diabetes and with cardiovascular risk factors such as abdominal obesity, hypertension, high LDL cholesterol levels and high triglyceride levels, which were also observed in those with prediabetes.

Is routine endocrine evaluation necessary after paediatric traumatic brain injury?

BACKGROUND: Traumatic brain injury (TBI) is a common event in childhood. It is a recognised cause of hypopituitarism both in adult and paediatric patients. Routine endocrine evaluation has been proposed for adult TBI-survivors; nevertheless, incongruous data have been reported in children. AIM: The goal of this study was to describe the prevalence of pituitary dysfunction after TBI in a cohort of children. MATERIAL/SUBJECTS AND METHODS: This is a cross-sectional study comprising retrospective medical record review and prospective testing. Children with brain injury discharged from the Paediatric Intensive Care Unit from year 2004 to 2009 were recruited. Height and weight were recorded, systemic examination was performed and baseline pituitary function tests were undertaken. Provocative tests were performed only if abnormal basal levels were detected. RESULTS: Thirty-six patients were collected; the mean age at assessment was 7.2 years and the mean interval since injury 3.3 years. All patients had skull fracture or intracranial haemorrhage; 36.6 % of them had moderate to severe TBI. No abnormalities were found on examination. Low serum IGF 1 levels were detected in four patients and two patients had low serum cortisol levels with inappropriately normal plasma ACTH concentrations. No evidence of pituitary dysfunction was observed in these patients after clinical follow-up, repeated baseline hormone levels or dynamic function tests. CONCLUSIONS: No endocrine sequelae have been detected in this population. The routine endocrine evaluation in children with mild to moderate TBI might not be justified, according to our findings.

Diagnosis and treatment of multiple endocrine neoplasia type 1 (MEN1).

Multiple endocrine neoplasia type 1 (MEN1; formerly known as Wermer syndrome) is a rare disorder characterized by the combined occurrence of two or more tumors involving parathyroid, pancreatic islets and anterior pituitary glands; some other tumors have also been described. In most cases it is inherited in an autosomic dominant manner but it may occur sporadically. The MEN1 gene (MEN1) is located on chromosome 11q13, it is composed of ten exons that encode a 610 amino acid protein called menin. Menin, with no homology to any other known protein, interacts with several different proteins and plays an important role in regulation of cell growth, cell cycle, genome stability and synapse plasticity. Familiar MEN1 has a high degree of penetrance with clinical or biochemical manifestations of the disease in 80% and 98%, respectively, by the fifth decade. Clinical manifestations are related to tumor localizations and their secretory products. Hyperparathyroidism is the most common feature of MEN1 (95% of patients), pancreatic islet tumors or pancreatic NET (neuroendocrine tumor) occur in 40-70% and pituitary tumors in 30-40% of MEN 1 patients. In addition, other tumors, such as adrenal cortical tumors, carcinoid tumors, lipomas, angiofibromas, colagenomas and meningiomas may be present. Occurrence of de novo mutations appear in 10% of all patients with MEN1. A correlation between genotype and phenotype has not been found and, even more, combinations of these tumors may be different in members of the same family. Untreated patients have a decreased life expectancy, with a 50% probability of death by the age of 50 years and the cause of death is mostly directly related to MEN1, being the most important causes malignant pancreatic neuroendocrine tumors (NET) and thymic carcinoids. Treatment for each type of endocrine tumor is generally similar as in non-MEN1 associated tumors, but results are less successful according to multiplicity of tumors, higher metastatic disease, larger and more aggressive tumors and more resistant to treatment. The prognosis might improve by preclinical tumor diagnosis and appropriated treatment.

Mediterranean diet adherence in individuals with prediabetes and unknown diabetes: the Di@bet.es Study.

BACKGROUND AND AIMS: Mediterranean diet (MedDiet) is causally related to diabetes and is a dietary pattern recommended to individuals with diabetes. We investigated MedDiet adherence in individuals with prediabetes and unknown (PREDM/UKDM) or known diabetes (KDM) compared to those with normal glucose metabolism (NORMAL). METHODS: This was a national, population-based, cross-sectional, cluster-sampling study. MedDiet adherence was scored (MedScore, mean ± SD 24 ± 5) using a qualitative food frequency questionnaire. Logistic regression was used to examine the association between MedScore and PREDM/UKDM or KDM versus control subjects. RESULTS: We evaluated 5,076 individuals. Mean age was 50 years, 57% were female, 826 (582/244) were PREDM/UKDM, 478 were KDM and 3,772 were NORMAL. Mean age increased across MedScore tertiles (46, 51 and 56 years, p < 0.0001). Higher age-adjusted adherence to MedDiet (5-unit increment in the MedScore) was associated with lower and nondifferent odds (OR, 95% CI) of prevalent PREDM/UKDM (0.88, 0.81-0.96, p = 0.001) and KDM (0.97, 0.87-1.07, p = 0.279), respectively, compared to individuals in the NORMAL group. CONCLUSIONS: In a representative sample of the whole Spanish population, MedDiet adherence is independently associated with PREDM/UKDM. Therapeutic intervention may be, in part, responsible for the lack of differences in adherence observed between the KDM and NORMAL groups. However, reverse causation bias cannot be ruled out in cross-sectional studies.

Prevalence of diabetes mellitus and impaired glucose regulation in Spain: the Di@bet.es Study.

AIMS/HYPOTHESIS: The Di@bet.es Study is the first national study in Spain to examine the prevalence of diabetes and impaired glucose regulation. METHODS: A population-based, cross-sectional, cluster sampling study was carried out, with target population being the entire Spanish population. Five thousand and seventy-two participants in 100 clusters (health centres or the equivalent in each region) were randomly selected with a probability proportional to population size. Participation rate was 55.8%. Study variables were a clinical and demographic structured survey, lifestyle survey, physical examination (weight, height, BMI, waist and hip circumference, blood pressure) and OGTT (75 g). RESULTS: Almost 30% of the study population had some carbohydrate disturbance. The overall prevalence of diabetes mellitus adjusted for age and sex was 13.8% (95% CI 12.8, 14.7%), of which about half had unknown diabetes: 6.0% (95% CI 5.4, 6.7%). The age- and sex-adjusted prevalence rates of isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT) and combined IFG-IGT were 3.4% (95% CI 2.9, 4.0%), 9.2% (95% CI 8.2, 10.2%) and 2.2% (95% CI 1.7, 2.7%), respectively. The prevalence of diabetes and impaired glucose regulation increased significantly with age (p < 0.0001), and was higher in men than in women (p < 0.001). CONCLUSIONS/INTERPRETATION: The Di@bet.es Study shows, for the first time, the prevalence rates of diabetes and impaired glucose regulation in a representative sample of the Spanish population.

Coexistence of two different pseudohypoparathyroidism subtypes (Ia and Ib) in the same kindred with independent Gs{alpha} coding mutations and GNAS imprinting defects.

BACKGROUND: Pseudohypoparathyroidism (PHP) defines a rare group of disorders whose common feature is resistance to the parathyroid hormone. Patients with PHP-Ia display additional hormone resistance, Albright hereditary osteodystrophy (AHO) and reduced Gsalpha activity in easily accessible cells. This form of PHP is associated with heterozygous inactivating mutations in Gsalpha-coding exons of GNAS, an imprinted gene locus on chromosome 20q13.3. Patients with PHP-Ib typically have isolated parathyroid hormone resistance, lack AHO features and demonstrate normal erythrocyte Gsalpha activity. Instead of coding Gsalpha mutations, patients with PHP-Ib display imprinting defects of GNAS, caused, at least in some cases, by genetic mutations within or nearby this gene. PATIENTS: Two unrelated PHP families, each of which includes at least one patient with a Gsalpha coding mutation and another with GNAS loss of imprinting, are reported here. RESULTS: One of the patients with GNAS imprinting defects has paternal uniparental isodisomy of chromosome 20q, explaining the observed imprinting abnormalities. The identified Gsalpha coding mutations include a tetranucleotide deletion in exon 7, which is frequently found in PHP-Ia, and a novel single nucleotide change at the acceptor splice junction of intron 11. CONCLUSIONS: These molecular data reveal an interesting mixture, in the same family, of both genetic and epigenetic mutations of the same gene.

Fatty liver index as a predictor for type 2 diabetes in subjects with normoglycemia in a nationwide cohort study.

Our aim was to evaluate whether fatty liver index (FLI) is associated with the risk of type 2 diabetes (T2DM) development within the Spanish adult population and according to their prediabetes status; additionally, to examine its incremental predictive value regarding traditional risk factors. A total of 2260 subjects (Prediabetes: 641 subjects, normoglycemia: 1619 subjects) from the Di@bet.es cohort study were studied. Socio-demographic, anthropometric, clinical data and survey on habits were recorded. An oral glucose tolerance test was performed and fasting determinations of glucose, lipids and insulin were made. FLI was calculated and classified into three categories: Low (< 30), intermediate (30-60) and high (> 60). In total, 143 people developed diabetes at follow-up. The presence of a high FLI category was in all cases a significant independent risk factor for the development of diabetes. The inclusion of FLI categories in prediction models based on different conventional T2DM risk factors significantly increase the prediction power of the models when all the population was considered. According to our results, FLI might be considered an early indicator of T2DM development even under normoglycemic condition. The data also suggest that FLI could provide additional information for the prediction of T2DM in models based on conventional risk factors.

The first clinical case of a mutation at residue K185 of Kir6.2 (KCNJ11): a major ATP-binding residue.

BACKGROUND: Closure of the adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channel plays a key role in insulin secretion from the pancreatic beta-cells. Many mutations in KCNJ11 and ABCC8, which respectively encode the pore-forming (Kir6.2) and regulatory (SUR1) subunits of the K(ATP) channel, cause neonatal diabetes. All such mutations impair the ability of metabolically generated ATP to close the channel. Although lysine 185 is predicted to be a major contributor to the ATP-binding site of Kir6.2, no mutations at this residue have been found to cause neonatal diabetes to date. METHODS: We report a 3-year-old girl with permanent neonatal diabetes (PNDM) caused by a novel heterozygous mutation (K185Q) at residue K185 of KCNJ11. The patient presented with marked hyperglycaemia and ketoacidosis at 70 days after birth, and insulin therapy was commenced. RESULTS: Wild-type and mutant K(ATP) channels were expressed in Xenopus oocytes and the effects of intracellular ATP on macroscopic K(ATP) currents in inside-out membrane patches were measured. In the simulated heterozygous state, the K185Q mutation caused a substantial reduction in the ability of MgATP to inhibit the channel. Heterozygous K185Q channels were still blocked effectively by the sulphonylurea tolbutamide. CONCLUSIONS: We report the first clinical case of a PNDM caused by a mutation at K185. Functional studies indicate that the K185Q mutation causes PNDM by reducing the ATP sensitivity of the K(ATP) channel, probably via a reduction in ATP binding to Kir6.2. Based on the experimental data, the patient was successfully transferred to sulphonylurea therapy.

Target setting in intensive insulin management is associated with metabolic control: the Hvidoere childhood diabetes study group centre differences study 2005.

OBJECTIVE: To evaluate glycaemic targets set by diabetes teams, their perception by adolescents and parents, and their influence on metabolic control. METHODS: Clinical data and questionnaires were completed by adolescents, parents/carers and diabetes teams in 21 international centres. HbA1c was measured centrally. RESULTS: A total of 2062 adolescents completed questionnaires (age 14.4 +/- 2.3 yr; diabetes duration 6.1 +/- 3.5 yr). Mean HbA 1c = 8.2 +/- 1.4% with significant differences between centres (F = 12.3; p < 0.001) range from 7.4 to 9.1%. There was a significant correlation between parent (r = 0.20) and adolescent (r = 0.21) reports of their perceived ideal HbA1c and their actual HbA1c result (p < 0.001), and a stronger association between parents' (r = 0.39) and adolescents' (r = 0.4) reports of the HbA1c they would be happy with and their actual HbA1c result. There were significant differences between centres on parent and adolescent reports of ideal and happy with HbA1c (8.1 < F > 17.4;p < 0.001). A lower target HbA1c and greater consistency between members of teams within centres were associated with lower centre HbA1c (F = 16.0; df = 15; p < 0.001). CONCLUSIONS: Clear and consistent setting of glycaemic targets by diabetes teams is strongly associated with HbA1c outcome in adolescents. Target setting appears to play a significant role in explaining the differences in metabolic outcomes between centres.

Incidence of diabetes mellitus in Spain as results of the nation-wide cohort di@bet.es study.

Our aim was to determine the incidence of type 2 diabetes mellitus in a nation-wide population based cohort from Spain (di@bet.es study). The target was the Spanish population. In total 5072 people older than 18 years,were randomly selected from all over Spain). Socio-demographic and clinical data, survey on habits (physical activity and food consumption) and weight, height, waist, hip and blood pressure were recorder. A fasting blood draw and an oral glucose tolerance test were performed. Determinations of serum glucose were made. In the follow-up the same variables were collected and HbA1c was determined. A total of 2408 subjects participated in the follow-up. In total, 154 people developed diabetes (6.4% cumulative incidence in 7.5 years of follow-up). The incidence of diabetes adjusted for the structure of age and sex of the Spanish population was 11.6 cases/1000 person-years (IC95% = 11.1-12.1). The incidence of known diabetes was 3.7 cases/1000 person-years (IC95% = 2.8-4.6). The main risk factors for developing diabetes were the presence of prediabetes in cross-sectional study, age, male sex, obesity, central obesity, increase in weight, and family history of diabetes. This work provides data about population-based incidence rates of diabetes and associated risk factors in a nation-wide cohort of Spanish population.

Exploring the diabetogenicity of the HLA-B18-DR3 CEH: independent association with T1D genetic risk close to HLA-DOA.

The objective of this study was to identify additional diabetes susceptibility markers in the MHC that could be responsible for the differential diabetogenicity of different HLA-DR3 CEHs. High-resolution SNP genotyping of the MHC was carried out in 15 type 1 diabetes (T1D) patients and 39 non-diabetic controls, homozygous for DR3-DQ2 and with one copy of the A(*)30-B(*)18-MICA(*)4-F1C30-DRB1(*)0301-DQB1(*)0201-DPB1(*)0202 HLA haplotype. Significantly associated SNPs were replicated in an independent sample of 554 T1D patients and 841 controls without HLA matching. Electrophoretic mobility shift assay was used to show a functional effect of an associated SNP. Seven SNPs showed evidence of association in the initial discovery experiment. Upon replication, only rs419434 (upstream HLA-DOA gene) remained significant. A functional variant (rs432375) in complete LD with rs419434 was shown to affect USF-1 binding and could be responsible for the association signal in the region. We have identified a new susceptibility locus within the MHC with a modest contribution to T1D (OR=1.93; CI: 1.52-2.44; P=10(-8)) that is independent of HLA-DRB1 locus.

Subcutaneous histamine versus botulinum toxin type A in migraine prophylaxis: a randomized, double-blind study.

OBJECTIVES: To compare the efficacy and tolerability of the subcutaneous administration of histamine and botulinum toxin type A (BoNTA) in migraine prophylaxis. BACKGROUND: Histamine has a selective affinity for H3 receptors and it may specifically inhibit the neurogenic edema response involved in migraine pathophysiology. METHODS: One hundred patients with migraine were selected in a 12-week double-blind controlled clinical trial to evaluate the efficacy of subcutaneous administration of histamine (1-10 ng twice a week) n = 50, compared with administration of 50 U of BoNTA (one injection cycle) n = 50. RESULTS: The data collected during the 4th week of treatment revealed a significant decrease in all parameters studied, in histamine and BoNTA (P < 0.001). After 4 weeks of treatment, but one injection cycle of 50 U BoNTA had only a 40-day period of efficacy. CONCLUSIONS: This randomized study demonstrated that both histamine and BoNTA are similarly effective and well tolerated in reducing or eliminating headache in migraine prophylaxis. Low doses of histamine applied subcutaneously may represent a novel and effective therapeutic alternative in migraine patients and lay the clinical and pharmacological groundwork for the use of H3 agonist in migraine prophylaxis.

Subcutaneous histamine versus topiramate in migraine prophylaxis: a double-blind study.

BACKGROUND: Histamine has a selective affinity for H3 receptors and it may specifically inhibit the neurogenic edema response involved in migraine pathophysiology. OBJECTIVE: To evaluate the therapeutic potential of subcutaneous administration of histamine in migraine prophylaxis, compared with oral administration of topiramate. METHODS: Ninety patients with migraine were selected in a 12-week double-blind controlled clinical trial to evaluate the efficacy of subcutaneous administration of histamine (1-10 ng twice a week) compared with oral administration of topiramate (100 mg daily dose). The variables studied were: headache intensity, frequency, duration, analgesic intake and Migraine Disability Assessment. RESULTS: The data collected during the 12 weeks of treatment revealed that headache symptoms improved in both the histamine and topiramate groups, which was evident within the first month after the initiation of treatment, with statistically significant (p < 0.001) reductions in headache frequency (50%), Migraine Disability Assessment score (75%), intensity of pain (51%), duration of migraine attacks (45%), as well as in the use of rescue medication (52%). CONCLUSION: The present study provides evidence of the efficacy of subcutaneously applied histamine and orally administered topiramate in migraine prophylaxis. Subcutaneously applied histamine may represent a novel and effective therapeutic alternative in resistant migraine patients.

Maturity Onset Diabetes of the Young (MODY) in Tunisia: Low frequencies of GCK and HNF1A mutations.

Maturity Onset Diabetes of the Young (MODY) is a monogenic form of diabetes characterized by autosomal dominant inheritance, an early clinical onset and a primary defect in ß-cell function. Mutations in the GCK and HNF1A genes are the most common cause of MODY among Caucasians. The etiology of MODY in Tunisia stills a challenge for researchers. The aim of this study was to screen for mutations in GCK, HNF1A, HNF4A and INS genes in North African Tunisians subjects, in whom the clinical profile was very suggestive of MODY. A total of 23 unrelated patients, with clinical presentation of MODY were tested for mutations in GCK, HNF1A, HNF4A and INS genes, using Denaturing High Performance Liquid Chromatography (DHPLC), Multiplex Ligation-depend Probe Amplification (MLPA) and sequencing analysis. We identified the previously reported mutation c-169C > T in one patient as well as a new mutation c-457C > T in two unrelated patients. No mutations were detected in the HNF1A and INS genes. Despite restrictive clinical criteria used for selecting patients in this study, the most common genes known for MODY do not explain the majority of cases in Tunisians. This suggests that there are others candidate or unidentified genes contributing to the etiology of MODY in Tunisians families.

Successful use of cinacalcet to treat parathyroid-related hypercalcemia in two pediatric patients.

Two pediatric patients with different causes of hyperparathyroidism are reported. First patient is a 13-year-old male with severe hypercalcemia due to left upper parathyroid gland adenoma. After successful surgery, calcium and phosphate levels normalized, but parathormone levels remained elevated. Further studies revealed a second adenoma in the right gland. The second patient is a 13-year-old female with uncommon hypercalcemia symptoms. Presence of pathogenic calcium-sensing receptor gene (CASR) mutation was found, resulting in diagnosis of symptomatic familial hypocalciuric hypercalcemia. Cinacalcet, a calcium-sensing agent that increases the sensitivity of the CASR, was used in both patients with successful results. LEARNING POINTS: Hyperparathyroidism is a rare condition in pediatric patients. If not treated, it can cause serious morbidity.Genetic tests searching for CASR or MEN1 gene mutations in pediatric patients with primary hyperparathyroidism should be performed.Cinacalcet has been effective for treating different causes of hyperparathyroidism in our two pediatric patients.Treatment has been well tolerated and no side effects have been detected.

Effect of cyclosporin A treatment on the production of antibody in insulin-dependent (type I) diabetic patients.

Anti-islet cell and anti-insulin antibody production was studies over a 12-mo period in 82 recently diagnosed diabetics randomly receiving either cyclosporin or placebo. Cyclosporin had only minimal effects on the production of anti-islet cell antibodies whether directed to islet cytoplasmic (immunofluorescence) or membrane (cytotoxicity assay) antigens even in patients undergoing remission. These data suggest that these antibodies do not play a major role in the pathogenesis of the disease particularly since their (irregular) presence is not predictive of the clinical response to cyclosporin. Conversely, cyclosporin completely suppressed the synthesis of antibodies elicited by exogenous insulin irrespective of the insulin doses received, and decreased the autoantibody production against thyroid antigens, indicating that cyclosporin has variable effects on antibody production against various antigens.

Islet cell autoantigen 69 kD (ICA69). Molecular cloning and characterization of a novel diabetes-associated autoantigen.

We have identified a novel 69-kD peptide autoantigen (ICA69) associated with insulin-dependent diabetes mellitus (IDDM) by screening a human islet lambda gt11 cDNA expression library with cytoplasmic islet cell antibody positive sera from relatives of IDDM patients who progressed to the overt disease. The deduced open reading frame of the ICA69 cDNA predicts a 483-amino acid protein. ICA69 shows no nucleotide or amino acid sequence relation to any known sequence in GenBank, except for two short regions of similarity with BSA. The ICA69 cDNA probe hybridizes with a 2-kb mRNA in poly(A+) RNA from human pancreas, brain, heart, thyroid, and kidney, but not with skeletal muscle, placenta, spleen, or ovary. Expression of ICA69 was also detected in beta cells and cell lines, as well as in tumoral tissue of islet cell origin. The native ICA69 molecule migrates to 69 kD in SDS-PAGE as detected with specific antibodies. Serum samples from relatives of IDDM patients specifically reacted with affinity-purified recombinant ICA69 on Western blotting. The structural gene for ICA69 was designated ICA1. A homologue in the mouse, designated Ica-1 was mapped to the proximal end of chromosome 6 (within 6 cM of the Met protooncogene). ICA69 adds a novel autoantigen to the family of identified islet target molecules, and by the manner of its identification and characterization large amounts of antigen are available for development of quantitative, convenient predictive assays for autoantibodies and analysis of the role of this molecule in diabetes autoimmunity, as well as its physiologic function.