BACKGROUND: Testing for autoantibodies against the zinc transporter ZnT8 (ZnTA) is becoming routine in pediatric diabetes. However, available data are inconclusive when focusing on adult-onset diabetes, including autoimmune diabetes, which does not require insulin at diagnosis (LADA). BASIC PROCEDURES: We examined the ZnTA prevalence and titers and matched them with the clinical phenotype and PTPN22 genotypes of Czech LADA patients who were positive for GADA and/or IA2A and had a fasting C-peptide level >200 pmol/L at diagnosis as well as HNF4A-, GCK- or HNF1A-MODY patients and healthy controls. MAIN FINDINGS: Most LADA patients were negative for ZnTA, and the sensitivity of the assay was only 18-20% for patients with LADA-like progression to insulinotherapy compared to healthy controls. In LADA patients, there was no association between the ZnTA and PTPN22 risk genotypes. LADA patients positive for ZnTA had a lower BMI than those positive for other autoantibodies alone. Importantly, MODY patients were completely negative for ZnTA, and the levels of ZnTA in MODY patients were similar to those in healthy controls. CONCLUSIONS: ZnTA quantification did not improve LADA diagnosis. However, positivity for ZnTA can be used as a negative MODY pre-diagnostic criterion even in the region of Central and East Europe, where other islet cell autoantibodies are common in MODY patients.

• MeSH
• autoprotilátky krev   imunologie   MeSH
• biologické markery krev   MeSH
• diabetes mellitus 1. typu krev   farmakoterapie   genetika   imunologie   MeSH
• diabetes mellitus 2. typu krev   farmakoterapie   genetika   imunologie   MeSH
• fenotyp MeSH
• genotyp MeSH
• hypoglykemika terapeutické užití   MeSH
• inzulin terapeutické užití   MeSH
• lidé středního věku MeSH
• lidé MeSH
• progrese nemoci MeSH
• tyrosinfosfatasa nereceptorového typu 22 genetika   MeSH
• zinkový transportér 8 krev   imunologie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

• Klíčová slova
• FOXA2, kardiovaskulární riziko,
• MeSH
• beta-buňky patologie   MeSH
• diabetes mellitus 2. typu * genetika   komplikace   patologie   terapie   MeSH
• hepatocytární jaderné faktory * fyziologie   genetika   MeSH
• hypoglykemika terapeutické užití   MeSH
• inzulin sekrece   terapeutické užití   MeSH
• játra enzymologie   metabolismus   MeSH
• lidé MeSH
• mutace MeSH
• poruchy metabolismu glukózy genetika   patologie   MeSH
• regulace genové exprese MeSH
• systém (enzymů) cytochromů P-450 MeSH
• transkripční faktory genetika   klasifikace   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

CONTEXT: Congenital hyperinsulinism of infancy (CHI) represents a group of heterogeneous disorders characterized by oversecretion of insulin from pancreatic β-cells causing severe hypoglycemia. OBJECTIVE: We studied the distribution of genetic causes of CHI in a Czech population. METHODS: Countrywide collection of patients with CHI included 40 subjects (12 females, median age of diagnosis, 1 wk [interquartile range, 1-612 wk]). We sequenced the ABCC8, KCNJ11, GLUD1, GCK, HADH, UCP2, SLC16A1, HNF4A, and HNF1A genes and investigated structural changes in the ABCC8 gene. We functionally tested novel variants in the ABCC8 gene by Rb(86+) efflux assay and novel variants in the HNF1A gene by transcriptional activation and DNA-binding tests. RESULTS: We found causal mutations in 20 subjects (50%): 19 carried a heterozygous mutation while one patient was homozygous for mutation in the ABCC8 gene. Specifically, we detected 11 mutations (seven novel) in ABCC8, one novel mutation in KCNJ11, five mutations (two novel) in HNF1A, two novel mutations in HNF4A, and one in GCK. We showed a decrease of activation by diazoxide in mutant KATP channels with novel ABCC8 variants by 41-91% (median, 82%) compared with wild-type (WT) channels and reduced transcriptional activity of mutant HNF1A proteins (2.9% for p.Asn62Lysfs93* and 22% for p.Leu254Gln) accompanied by no DNA-binding ability compared with WT HNF1A. CONCLUSION: We detected a higher proportion of heterozygous mutations causing CHI compared with other cohorts probably due to lack of consanguinity and inclusion of milder CHI forms. Interestingly, HNF1A gene mutations represented the second most frequent genetic cause of CHI in the Czech Republic. Based on our results we present a genetic testing strategy specific for similar populations.

• MeSH
• aktivace transkripce MeSH
• DNA genetika   MeSH
• dospělí MeSH
• draslíkové kanály dovnitř usměrňující genetika   MeSH
• genetická variace MeSH
• hepatocytární jaderný faktor 1-alfa genetika   MeSH
• hepatocytární jaderný faktor 4 genetika   MeSH
• kohortové studie MeSH
• kojenec MeSH
• lidé MeSH
• mutace genetika   MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• protein-serin-threoninkinasy genetika   MeSH
• radioizotopy rubidia MeSH
• receptory sulfonylurey genetika   MeSH
• rodokmen MeSH
• těhotenství MeSH
• vrozený hyperinzulinismus epidemiologie   genetika   MeSH
• Check Tag
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

• Publikační typ
• abstrakt z konference MeSH

BACKGROUND: The protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene encodes lymphoid tyrosine phosphatase (LYP), which is expressed primarily in lymphoid tissues. The functional but geographically highly variable PTPN22 single-nucleotide polymorphisms (SNPs), particularly c.1858C>T, contribute to the onset and progression of autoimmunity-associated diseases and facilitate the expression of disease-associated autoantibodies. In Central Europe, 17-25% of patients with monogenic diabetes (maturity-onset diabetes of the young, MODY) transiently express islet cell autoantibodies. METHODS: We addressed the links between the functional and geographically variable PTPN22 SNPs with MODY manifestation and the expression of islet cell autoantibodies in 276 MODY patients who originated from four regions (the Czech Republic, Israel, Japan and Brazil). RESULTS: The frequency of PTPN22 polymorphisms in the MODY patients was similar to those in geographically matched healthy populations, with the exception of c.788G>A, the minor allele frequency of which was significantly elevated in the Czech hepatocyte nuclear factor 1-α (HNF1A) MODY patients [odds ratio (OR) 4.8, 95% confidence interval (CI) 2.2-10.7] and the Brazilian MODY patients (OR 8.4, 95% CI 1.8-39.1). A barely significant increase in the c.788G>A minor allele was also detected in the islet cell autoantibody-positive Czech MODY patients. However, c.788A behaves as a loss-of-function mutant in T cells, and thus protects against autoimmunity. CONCLUSIONS: MODY patients (including islet cell autoantibody-positive cases) do not display any increase in autoimmunity-associated PTPN22 alleles. The absence of autoimmunity-associated PTPN22 alleles was also demonstrated in latent autoimmune diabetes in adults, which suggests that the slow kinetics of the onset of autoantibodies is subject to a regulation that is different from that experienced in type 1 diabetes and other autoimmune disorders.

• MeSH
• autoimunita genetika   imunologie   MeSH
• autoimunitní nemoci genetika   imunologie   MeSH
• autoprotilátky krev   MeSH
• diabetes mellitus 2. typu genetika   imunologie   MeSH
• dospělí MeSH
• genetická predispozice k nemoci MeSH
• jednonukleotidový polymorfismus MeSH
• Langerhansovy ostrůvky cytologie   imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• T-lymfocyty imunologie   MeSH
• tyrosinfosfatasa nereceptorového typu 22 genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Brazílie MeSH
• Česká republika MeSH
• Izrael MeSH
• Japonsko MeSH

AIMS: Islet cell autoantibodies are associated with autoimmune insulitis and belong to the diagnostic criteria of type 1 diabetes mellitus. However, growing evidence suggests that autoantibodies are present in other types of diabetes. Here, we focus on the autoantibody incidence in Czech patients with maturity-onset diabetes of the young and analyse their functional relevance in terms of diabetes onset and control. METHODS: Autoantibodies against glutamic acid decarboxylase (GAD) 65 and protein tyrosine phosphatase islet antigen 2 (IA-2) were measured in a cohort of 28 Czech patients with maturity-onset diabetes of the young, all confirmed by genetic testing. Selected clinical data were correlated to the status and kinetics of autoantibodies. RESULTS: One quarter of patients with maturity-onset diabetes of the young examined (7/28; 25%) was positive for GAD or IA-2 autoantibodies. GAD autoantibodies were more prevalent (7/7) than IA-2 autoantibodies (1/7). The incidence of autoantibodies did not correlate with human leukocyte antigen status. The patients who were positive for the autoantibodies developed diabetes later than those who were autoantibody-negative, but had worse glycaemic control (increased HbA1c ). Expression of autoantibodies decreased with any improvement of diabetes compensation. Only one patient did not correspond to the above and displayed signs of combined signs of maturity-onset diabetes of the young and Type 1 diabetes. CONCLUSIONS: The data suggest transient but highly prevalent islet cell autoantibody expression in Czech patients with maturity-onset diabetes of the young. The autoantibodies were found in patients with delayed diabetes onset, and in times of insufficient diabetes control. As improvement of glycaemic control was associated with a decrease in levels of autoantibodies, their presence may reflect the kinetics of β-cell destruction induced by causes other than autoimmune ones.

• MeSH
• autoprotilátky imunologie   MeSH
• diabetes mellitus 2. typu epidemiologie   imunologie   metabolismus   MeSH
• dítě MeSH
• dospělí MeSH
• glukokinasa genetika   MeSH
• glutamát dekarboxyláza imunologie   MeSH
• glykovaný hemoglobin metabolismus   MeSH
• hepatocytární jaderný faktor 1-alfa genetika   MeSH
• hepatocytární jaderný faktor 4 genetika   MeSH
• kohortové studie MeSH
• Langerhansovy ostrůvky imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• tyrosinfosfatasy receptorového typu, třída 8 imunologie   MeSH
• věk při počátku nemoci MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

It was recently suggested that routine islet cell autoantibody testing should be performed to discriminate maturity-onset diabetes of the young (MODY) from type 1 diabetes mellitus (T1DM). This is the first report ever to describe the familial manifestation of T1DM autoimmunity in nonobese HNF1A-MODY subjects and the presence of islet antigen-2 (IA-2) antibodies in MODY subjects. Three nonobese subjects in an age range of 14-35 years were diagnosed with HNF1A-MODY (p. Arg159Gln mutation). All the tested subjects had detectable (but varying) levels of islet cell autoantibodies (i.e., antibodies against glutamate decarboxylase or IA-2) in the absence of other T1DM characteristics. They displayed long-term expression of intermediate fasting C-peptide levels, ketoacidosis was absent even in periods of spontaneous insulin withdrawal, and full dependence on externally administered insulin was not detected in any of them although better glycemic control was achieved when insulin was supplemented. The course of the disease was similar to that of the autoantibody-negative HNF1A-MODY subjects. The case questions the selectivity of autoantibodies as a marker of T1DM or late-onset autoimmune diabetes of adulthood (LADA) over MODY and challenges the use of autoantibodies as a universal negative marker of MODY in an effort to decrease the cost of health care, as it may eventually lead to the wrong diagnosis and thus to the incorrect treatment. Further research should involve examination of the autoantibody titers and prevalence in large and geographically diverse cohorts of MODY subjects selected for genetic testing (regardless of their autoantibody titers) as well as determination of the islet cell autoantibody kinetics in the course of MODY onset and progression.

• MeSH
• autoprotilátky krev   diagnostické užití   MeSH
• beta-buňky imunologie   patologie   MeSH
• diabetes mellitus 2. typu diagnóza   MeSH
• dospělí MeSH
• genetické testování MeSH
• hepatocytární jaderný faktor 1-alfa genetika   imunologie   MeSH
• lidé MeSH
• mladiství MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH

• Publikační typ
• abstrakt z konference MeSH

• Publikační typ
• abstrakt z konference MeSH

AIMS/HYPOTHESIS: MODY (Maturity Onset Diabetes of the Young) is an autosomal dominant inherited type of diabetes with significant genetic heterogeneity. New mutations causing MODY are still being found. A genetically confirmed diagnosis of MODY allows application of individualized treatment based on the underlying concrete genetic dysfunction. Detection of novel MODY mutations helps provide a more complete picture of the possible MODY genotypes. MATERIALS AND METHODS: We tested 43 adult Czech patients with clinical characteristics of MODY, using direct sequencing of HNF1A (hepatocyte nuclear factor 1-alpha), HNF4A (hepatocyte nuclear factor 4-alpha) and GCK (glucokinase) genes. RESULTS: In three Czech families we identified three novel mutations we believe causing MODY-two missense mutations in HNF1A [F268L (c.802T>C) and P291S (c.871C>T)] and one frame shift mutation in GCK V244fsdelG (c.729delG). Some of the novel HNF1A mutation carriers were successfully transferred from insulin to gliclazide, while some of the novel GCK mutation carriers had a good clinical response when switched from insulin or oral antidiabetic drugs to diet. CONCLUSION: We describe three novel MODY mutations in three Czech families. The identification of MODY mutations had a meaningful impact on therapy on the mutation carriers.

• MeSH
• diabetes mellitus farmakoterapie   genetika   MeSH
• dietoterapie MeSH
• fenotyp MeSH
• gliklazid terapeutické užití   MeSH
• glukokinasa genetika   MeSH
• hepatocytární jaderný faktor 1-alfa genetika   MeSH
• hepatocytární jaderný faktor 4 genetika   MeSH
• hypoglykemika MeSH
• inzulin terapeutické užití   MeSH
• lidé MeSH
• mutace MeSH
• rodokmen MeSH
• výsledek terapie MeSH
• zdraví rodiny MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Československo MeSH