When do we need to suspect maturity onset diabetes of the young in patients with type 2 diabetes mellitus?

ABSTRACT Objetivo: Maturity onset diabetes of the young (MODY) patients have clinical heterogeneity as shown by many studies. Thus, often it is misdiagnosed to type 1 or type 2 diabetes(T2DM). The aim of this study is to evaluate MODY mutations in adult T2DM patients suspicious in terms of MODY, and to show clinical and laboratory differences between these two situations. Subjects and methods: In this study, we analyzed 72 type 2 diabetic patients and their relatives (35F/37M) who had been suspected for MODY and referred to genetic department for mutation analysis. The gene mutations for MODY have been assessed in the laboratory of Marmara University genetics. Totally 67 (32F/35M; median age 36.1) diabetic patients were analyzed for 7 MODY mutations. Twelve patients who have uncertain mutation (VUS) were excluded from study for further evaluation. MODY(+) (n:30) patients and T2DM patients (n:25) were compared for clinical and laboratory parameters. Results: In MODY(+) subjects, mutations in GCK (MODY 2) (n:12; 40%) were the most common followed by HNF4A (MODY 1) (n:4; 13.3%). Diabetes diagnosis age was younger in MODY(+) group but not statistically significant. Sixty-six percent of MODY(+) subjects had diabetes history at 3-consecutive generations in their family compared with 28% of T2DM patients statistically significant (p:0.006). Gender, BMI, C-peptide, HbA1c, lipid parameters, creatinine, GFR, microalbuminuria, vitamin D and calcium were not statistically different between the groups. Conclusion: According to present study results, MODY mutation positivity is most probable in young autoantibody (-) diabetic patients diagnosed before 30 years of age, who have first degree family history of diabetes.

MODY 2 causado por mutaciones en la glucoquinasa: una aproximación a nivel molecular / MODY 2 caused by glucokinase mutations: a molecular approach

La diabetes MODY 2 es un tipo de diabetes monogénica producida por una mutación en la enzima glucoquinasa, generando un fenotipo hiperglicémico. Para posibles fines terapéuticos o de diagnóstico, se debe conocer esta proteína, una enzima monomérica de la familia de las hexoquinasas, encargadas de convertir glucosa en glucosa-6-fosfato, el primer paso de la glicolisis. La glucoquinasa se caracteriza por sus propiedades cinéticas únicas: tiene una afinidad mucho menor por el sustrato que las demás hexoquinasas y no es inhibida por su producto. Se encuentra principalmente en páncreas e hígado (ßGK y LGK, respectivamente), donde como sensor regula los distintos estados metabólicos de estos tejidos, y controla la glicemia a nivel sistémico. Las formas ßGK y LGK se diferencian a nivel transcripcional, pues el gen posee dos promotores distintos, específicos para cada tejido. A nivel hormonal, la actividad de esta enzima es regulada selectivamente de manera tejido-específica por glucosa, insulina y otras proteínas reguladoras. La isoforma hepática puede ser secuestrada hacia el núcleo por la proteína reguladora de glucoquinasa (GKRP, por su sigla en inglés). La principal característica de la enzima glucoquinasa es su inusual regulación alostérica, propiedad que le permite adoptar dos conformaciones principales, una cerrada (activa) y otra súper-abierta (inactiva). Se han desarrollado distintas drogas activadoras de glucoquinasa, las cuales se unen al sitio alostérico de la enzima y estabilizan a la proteína en su estado cerrado. En esta revisión se describen las características estructurales y propiedades regulatorias que posee la enzima glucoquinasa, relacionándolas con su rol en el desarrollo de la diabetes MODY 2. También se profundiza en las implicancias moleculares de algunas mutaciones descritas que originan MODY 2, y se abordan los efectos de moléculas activadoras de glucoquinasa.

Diabetes MODY 2 or GCK-MODY is a type of monogenic diabetes produced by a mutation in the glucokinase enzyme, generating a hyperglycemic phenotype. This protein, a monomeric enzyme of the hexokinase family, is responsible for converting glucose into glucose-6-phosphate, the first step of glycolysis. Glucokinase is characterized by its unique kinetic properties: it has a much lower affinity for its substrate than other hexokinases and is not inhibited by its product. It is found mainly in pancreas (ßGK) and liver (LGK), where it acts as a sensor regulating the different metabolic states of these tissues, and ultimately, controlling systemic glycemia. The two forms ßGK and LGK differ at a transcriptional level, because the gene presents two different tissue-specific promoters. The activity of glucokinase in liver and pancreas is regulated by glucose, insulin and other regulatory proteins. The liver isoform can be sequestered to the nucleus by the glucokinase regulatory protein (GKRP). The main characteristic of the enzyme is its unusual allosteric regulation, a property that allows the protein to adopt a closed (active) conformation, and a super-open (inactive) conformation. Different glucokinase activating drugs have been developed, which bind to the allosteric site of the enzyme and stabilize glucokinase in its closed state. This review describes the structural and regulatory properties of the glucokinase enzyme, and its role in the development of MODY 2 diabetes. The molecular implications of some mutations that originate MODY 2 are also described, and the effects of glucokinase activating molecules are addressed.

Clinical and Genetic Heterogeneity of Familial Early-Onset Diabetes: Case of Six Tunisian Patients Suspected of Maturity-Onset Diabetes of the Young 12

Background and objective: Maturity-onset diabetes of the young 12 (MODY12) is a form of early-onset type 2 diabetes, which is transmitted in an autosomal dominant mode. It has clinical features similar to MODY1 and MODY3. The aim of this study is to screen for mutations in ABCC8 gene in six Tunisian patients suspected of MODY12 using Sanger sequencing. Methods: Six probands, with diabetes in 2-3 generations and found previously negative for mutations in HNF1A, HNF4A, INS, IPF1 and NEUROD1, were screened for known mutations in ABCC8 gene using Sanger sequencing. A comparison of the clinical features of our patients with MODY12 cohorts of other studies was also performed using ANOVA test. Results: The six patients were diagnosed with overt diabetes (fasting glycemia: 12.85 ± 3.5 mmol/l, HbA1c: 12.51 ± 2.58%) at mean age of 25.16 ± 5.11 years. They had a BMI mean equal to 26.7 ± 5.9 kg/m2. The majority of the patients were initially treated with OHA or on diet. Some of them converted to insulin therapy. Although, the comparison of our cohort with other MODY12 cohorts showed no significant difference in age at diagnostic and HbA1c, molecular analysis showed only two synonymous non-pathological polymorphisms rs1799857 and rs1805036. Conclusion: Our study highlighted the clinical and genetic heterogeneity of familial earlyonset diabetes in the Tunisian population, which is concordant with previous studies Thus, the need for using nextgeneration sequencing technologies to determine the aetiology of these forms of diabetes.

MODY probability calculator for GCK and HNF1A screening in a multiethnic background population

ABSTRACT Objective We aimed to identify the frequency of monogenic diabetes, which is poorly studied in multiethnic populations, due to GCK or HNF1A mutations in patients with suggestive clinical characteristics from the Brazilian population, as well as investigate if the MODY probability calculator (MPC) could help patients with their selection. Subjects and methods Inclusion criteria were patients with DM diagnosed before 35 years; body mass index < 30 kg/m2; negative autoantibodies; and family history of DM in two or more generations. We sequenced HNF1A in 27 patients and GCK in seven subjects with asymptomatic mild fasting hyperglycemia. In addition, we calculated MODY probability with MPC. Results We identified 11 mutations in 34 patients (32.3%). We found three novel mutations. In the GCK group, six cases had mutations (85.7%), and their MODY probability on MPC was higher than 50%. In the HNF1A group, five of 27 individuals had mutations (18.5%). The MPC was higher than 75% in 11 subjects (including all five cases with HNF1A mutations). Conclusion Approximately one third of the studied patients have GCK or HNF1A mutations. Inclusion criteria included efficiency in detecting patients with GCK mutations but not for HNF1A mutations (< 20%). MPC was helpful in narrowing the number of candidates for HNF1A screening.

Searching for mutations in the HNF1B gene in a Brazilian cohort with renal cysts and hyperglycemia

ABSTRACT Objective To verify the presence of variants in HNF1B in a sample of the Brazilian population selected according to the presence of renal cysts associated with hyperglycemia. Subjects and methods We evaluated 28 unrelated patients with clinical suspicion of HNF1B mutation because of the concomitant presence of diabetes mellitus (DM) or prediabetes and renal cysts. Genotyping was accomplished using Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). In positive cases, available relatives were recruited. Results We found two patients with HNF1B mutations. The first presented the variant p.Pro328Leufs*48(c.983delC) and had DM, renal cysts, and hypomagnesemia. The second presented a heterozygous whole gene deletion in HNF1B, DM, renal cysts, body and tail pancreatic agenesis, and hypomagnesemia; this alteration was also found in his two siblings and his father. Conclusion The recruitment of suspected cases of HNF1B gene mutations in Brazilians due to hyperglycemia and renal cysts presents two positive cases. Our cases contribute to the annotation of clinical and biochemical phenotypes of this rare form of maturity-onset diabetes of the young (MODY).

Detection of novel mutations related to maturity-onset diabetes of the young / 基础医学与临床

Objective To find novel genes related to maturity-onset diabetes of the young(MODY)or novel muta-tions of known MODY related genes and provide the basis for MODY diagnosis. Methods Taking the major clinical features of MODY as screening criteria,we selected four patients from the Endocrine Department of Peking Union Medical College Hospital and prepared their genomic DNA sample for whole exome sequencing.PCR and Sanger se-quencing are used to validate the sequencing results. Results Two novel mutations of the GCK gene and HNF4α gene, c.1348G>T(p.Ala450Thr)and c.758G>A(p.Arg253Gln)were found in two patients. Conclusions These two patients are both MODY patients and this is the first time the novel mutations were found.

Diabetes MODY 2: reporte de dos casos con nueva mutación en el gen de glucokinasa / MODY 2: report of two cases with a new gene mutation in GCK

La diabetes MODY (Maturity Onset Diabetes of the Young) comprende un grupo heterogéneo de enfermedades monogénicasque se caracterizan por la disfunción de las células β. Se estima que ellas son responsables de 2-5% de los casos de diabetes. Seconocen más de 200 mutaciones en el gen de la glucoquinasa (GCK). En este trabajo se expone el caso de dos hermanas enlas cuales se realizó el diagnóstico de MODY 2 a través del estudio genético, hallándose una mutación del gen de la GCK nodescripto previamente en la bibliografía.

MODY (maturity onset diabetes of the young) includes a heterogeneous group of monogenic diseases which are characterized bydysfunction of beta cells. It accounts for 2-5% of all cases of diabetes. Over 200 mutations in the glucokinase (GCK) gene are known.In this paper we discuss the cases of two sisters in which the diagnosis of MODY 2 was performed by genetic studies, and report thefinding of a mutation in the GCK gene not previously described in the literature.

Aspectos más recientes en relación con la diabetes mellitus tipo MODY / Most recent aspects about type MODY diabetes mellitus

Antecedentes: la mejor comprensión fisiopatológica de la diabetes mellitus permite identificar diferentes tipos, entre ellos una variante monogénica denominada por sus siglas en inglés MODY (Maturity-Onset Diabetes of the Young). Objetivos: describir los aspectos fisiopatológicos, clínicos, diagnósticos y terapéuticos de los diferentes subtipos MODY. Desarrollo: los pacientes con diabetes tipo MODY presentan un comportamiento similar a la diabetes mellitus del adulto. Se caracteriza por una alteración genética autosómica dominante inherente y primaria a un defecto en la secreción de insulina. Hasta el momento actual se aceptan 9 subtipos de MODY. Los subtipos 1, 3, 4, 5 y 6 afectan a genes que codifican a factores nucleares de trascripción, y el subtipo 2 al gen que codifica a la enzima glucoquinasa. Se caracterizan clínicamente por cuadros que oscilan entre hiperglucemias permanentes, leves o moderadas, con buen pronóstico clínico, y pocas complicaciones, hasta cuadros de hiperglucemias mantenidas acompañadas de complicaciones crónicas precoces y graves. Conclusiones: las personas que padecen diabetes tipo MODY no son tan infrecuentes como se piensa. La correcta y temprana identificación de la enfermedad permitirá una acción terapéutica más racional y adecuada para brindar la posibilidad de mejor calidad de vida de estas personas(AU)

Background: a better physiopathological understanding of diabetes mellitus allows identifying its different types such as a monogenic variant called MODY (maturity-onset diabetes of the young). Objectives: to describe the physiopathological, clinical, diagnostic and therapeutic aspects of the different subtypes in MODY diabetes. Development: the patients with MODY diabetes behave similarly to those suffering diabetes mellitus in adults. It is characterized by inherited dominant autosomal genetic alteration which is primary to a defect in insulin secretion. Up to the present, 9 subtypes are accepted. The subtypes 1,3,4,5 and 6 affect gens coding for nuclear transcriptional factors whereas subtype 2 affects the gen coding for glycokinase enzyme. From the clinical viewpoint, they are characterized by conditions ranging from permanent, slight or moderate hyperglycemias, with good clinical prognosis and low complications, to sustained hyperglycemias accompanied by early chronic and serious complications. Conclusions: the people suffering MODY diabetes are not as uncommon as one might think. The correct and early detection will allow taking quick, adequate and more rational therapeutic actions to provide the patients with a better quality of life(AU)

MODY Syndrome / 대한소아내분비학회지

Maturity-onset diabetes of the young (MODY) is a heterogenous form of diabetes characterized by the early onset of diabetes, autosomal dominant inheritance, and impaired insulin secretion. MODY is mostly caused by mutations of the hepatocyte nuclear factor 1-alpha (HNF1-alpha) and glucokinase genes in Caucasians. However most Korean, Japanese, and Chinese patients with MODY do not express known MODY genes. The cause of MODY in Asians has not yet been elucidated clearly. This review focuses on studies on Asian patients with MODY.

Management of maturity-onset diabetes of the young (MODY)

La diabetes de tipo MODY (maturity-onset diabetes of the young) afecta entre 1 y 5% de los pacientes con diabetes en los Estados Unidos y otras naciones industrializadas. Las tres características más importantes de esta entidad son: desarrollo de diabetes antes de la edad de 25 a 30 años en ausencia de autoanticuerpos pancreáticos, transmisión genética autosómica dominante y evidencia de secreción residual de insulina. Existen seis subtipos de MODY de los cuales, el tipo 2 (mutación de la glucoquinasa-GKS) y el tipo 3 (mutación del factor nuclear hepático 1 alfa (HNF-1-alfa) son los más prevalentes (70% de todos los casos de diabetes de tipo MODY). Las sulfonilureas son la medicación de primera línea tanto en los niños como en los adultos, cuando la terapia dietética no es suficiente para normalizar la glicemia. Aunque los pacientes con subtipos 1, 3, y 4 usualmente responden bien a la terapia oral con sulfonilureas, un porcentaje significativo de pacientes con los subtipos 1 y 3 necesitan terapia con insulina debido a un deterioro progresivo de las células beta del páncreas. El mantenimiento de un estilo de vida activo y un peso normal, son recomendaciones esenciales en todos los pacientes con diabetes de tipo MODY.

Maturity-Onset Diabetes of the Young (MODY) affects 1-5% of people with diabetes in the USA and other industrialized countries. The three main features of MODY include: Development of diabetes before the age of 25 to 30 in absence of pancreatic antibodies, autosomal dominant inheritance, and evidence of residual insulin secretion. There are six subtypes of MODY of which, MODY2 (GCK mutation) and MODY3 (HNF1-alphaƒnmutation) are the most prevalent, accounting for more than 70% of cases. Sulfonylureas (SUs) remain the medication of first choice in children and adults when dietary therapy is insufficient to maintain normoglycemia. Although patients with MODY1, 3, and 4 usually respond very well to oral SUs, due to progressive beta-cell failure, a significant proportion of MODY1 and MODY3 patients may eventually require insulin therapy. Leading an active lifestyle and maintaining a normal weight are essential recommendations for all MODY patients.

Construction of a mutation due to a fourteen base-pair insertion in HNF-1α gene causing maturity-onset diabetes of the young (MODY) in Thai patients.

Objective: The aim of this study is to generate a mutation causing maturity-onset diabetes of the young (MODY) in Thai patients by insertion of a fourteen base-pair (bp) into a HNF-1a gene using a modified site-directed ligase-independent mutagenesis (SLIM) method. Methods: Two pairs of long- and short-tailed primers were designed to amplify a plasmid construct containing a HNF-1a and to insert a 14-bp at a desired position. Long-tailed primers contained the overhanging 14-nucleotide (nt) insert at their termini which were complementary to each other. Polymerase chain reactions (PCR) were performed in two separated tubes using different pairs of primers. After amplifications, PCR products from both tubes were pooled together, denatured and then re-annealed to allow formation of double stranded DNA molecules containing the 14-bp insert within HNF-1a. The pooled and reannealed PCR products without ligation were transformed into competent E.coli cells to generate a ligated recombinant plasmid with a 14-bp insertion. Results: Five of 14 bacterial colonies contained the desired recombinant plasmid with a 14-bp insertion within HNF-1a The efficiency of the method for generation of recombinant plasmid was about 36 percent. Conclusion: This method is simple and rapid to insert a long stretch of nucleotides into a plasmid construct containing a gene of interest at a desired position. A recombinant plasmid containing an insertion mutation in a HNF-1a gene was successfully generated, allowing an opportunity to perform functional study of the mutated gene.

Mutation Screening of HNF-1alpha Gene in Korean Women with Gestational Diabetes Mellitus / 당뇨병

BACKGROUNDS: Gestational diabetes mellitus (GDM) is defined as glucose intolerance with onset or first detection during pregnancy and mostly caused by insulin resistance and beta-cell dysfunction like type 2 diabetes. However, autoimmune or monogenic diabetes can contribute to GDM. Maturity-onset diabetes of the young (MODY) is a monogenic form of diabetes characterized by an early age of onset and an autosomal dominant pattern of inheritance. Most MODY cases are attributable to mutations in HNF-1alpha gene, also known as MODY3. We investigated whether mutations in HNF-1alpha gene are present in Korean women with GDM. METHODS: A total of 96 Korean women with GDM who have a family history of DM were screened for mutations in the HNF-1alpha gene. We evaluated the clinical characteristics of GDM women with HNF-1alpha gene mutations. RESULTS: Five of 96 patients (5.2%) were found to have a mutation in HNF-1alpha gene. Four of those (-23C > G, 833G > A (Arg278Gln), 923C > T, IVS5 + 106A > G) were novel and one (-124G > C) in promoter region was reported in previous study. The mean age of GDM women with mutations of HNF-1alpha gene was 34 years. Four women with MODY3 gene mutations required insulin therapy during pregnancy. GDM women with MODY3 gene mutations appeared to be decreased insulin secretion (HOMA-%B) than those without mutations. CONCLUSIONS: We have found the existence of MODY3 as well as novel HNF-1alpha gene mutations in Korean women with GDM.

Hepatocyte nuclear factor 1-alpha mutation in normal glucose-tolerant subjects and early-onset type 2 diabetic patients

BACKGROUND/AIMS: The prevalence of diabetes in Korea is reported to be approximately 10%, but cases of maturity-onset diabetes of the young (MODY) are rare in Korea. A diagnostic technique for autosomal dominant MODY is being actively sought. In this regard, we used a DNA chip to investigate the frequency of mutations of the MODY3 gene (hepatocyte nuclear factor-1alpha) in Korean patients with early-onset type 2 diabetes. METHODS: The genomic DNA of 30 normal individuals [age, 24.9+/-8.6 years] and 25 patients with early-onset type 2 diabetes (age, 27+/-5.9 years) was extracted, and the MODY3 gene was amplified. The amplified DNA was hybridized onto a MODY3 chip, which has oligonucleotides of 15-25 bases, representing wild-type and mutant MODY3 sequences in both forward and reverse orientations, immobilized on its surface. RESULTS: Among the normal subjects, there was no mutation of MODY3. Among those with early-onset type 2 diabetes, there was one case of MODY3 mutation. CONCLUSIONS: Our results indicate that MODY3 mutations are not rare in Korean early-onset type 2 diabetes patients in Korea and suggest that MODY3 mutations in patients with early-onset type 2 diabetes need to be further evaluated.

The Prevalence of Maturity Onset Diabetes of the Young(MODY) 3 in Children with Type 2 Diabetes Mellitus / 소아과

PURPOSE: Maturity-onset diabetes of the young(MODY) is a subtype of type 2 diabetes defined by autosomal dominant mode of inheritance, onset of diabetes usually before the age of 25 yrs, and a primary defect in the function of the beta cells of the pancreas. MODY3 is known as the most common form and is caused by mutations in hepatocyte nuclear factor(HNF)-1alpha. We examined the prevalence of MODY3 in children with type 2 diabetes mellitus(DM). METHODS: Children with type 2 DM(N=17) and their family members with type 2 DM(N=5) were enrolled. Inclusion criteria for the children were fasting C-peptide and postprandial C-peptide more than 1.0 ng/mL and 1.5 ng/mL respectively, familial type 2 DM in at least two generations, and body mass index(BMI)(kg/m(2)) less than 95th percentile. Genomic DNA was extracted from blood samples. We analyzed HNF-1alpha for mutation by DNA microarray method and direct sequencing. RESULTS: We found one case with a mutation of the promoter region of HNF-1alpha(5'-ctaGGCTAGTGGGGTTTTGCGGGGGCAGTGGGTGCAAGG-3') in one child's family member among 22 children and adult subjects with type 2 DM. CONCLUSION: Although we found a mutation of HNF-1alpha in an adult family member with type 2 DM, we did not find this mutation in a child with type 2 DM. The further investigation of MODY in children, including other types, is required.

Molecular scanning for MODY5 mutation in Beijing population of familial early-onset type 2 diabetes / 第三军医大学学报

T,1 mutation in coding region including A513T. No target gene mutations were found in 100 controls.Conclusion No enough evidence demonstrates that the variation in or near MODY5 genes is the major cause of early-onset type 2 diabetes in Beijing population.A novel mutation of MODY5 gene was found to possibly relate to diabetes,which mechanism needs to be proved by further study of protein function.

A Case of Early Manifested Long-term Complications in MODY(Maturity Onset Diabetes in Young) Patient / 대한소아내분비학회지

A 14-year old boy presented with myoclonic seizure with rightward deviation of eyeballs. Three years ago, he was diagnosed as diabetes necessitating insulin injection. At that time, his blood glucose was 448mg/dl, HbA1c 27.8%, serum C-peptide rose from 0.4 to 1.1ng/ml after glucagon, and 24 hour urine C-peptide was 6.7microg/day. Eye examination was normal. His maternal grandmother died of diabetes at 50 years old, and his mother's sister and his elder sister had NIDDM with oral hypoglycemics. But, he didn't control hyperglycemia himself since that time. On physical exam, his grasping power was decreased in right hand, and cataract was detected at the posterior pole of lenses in both eyes requiring surgery. EEG showed partial seizure disorder in left frontoparietal area, and MRI revealed cerebral infarction in left frontoparietal cortex. Sensory-motor polyneuropathy was noted in nerve conduction velocity. His neurologic symptom was improved gradually with insulin therapy, but nerve conduction velocity and MRI abnormalities did not improved after 6 months of follow-up. Although long-term diabetic complication is common in poorly controlled diabetes, very early manifested eye and nervous system complications like this case is extremely uncommon.