A case of diabetes mellitus with glucokinase regulator gene mutation misdiagnosed as type 1 diabetes / 中华内分泌代谢杂志

We report a case of a female teenage with monogenic diabetes mellitus caused by glucokinase regulator (GCKR) gene mutation who presented with diabetic ketosis and misdiagnosed as type 1 diabetes. The patient was treated with insulin for 3 years since diagnosis. The islet function was well preserved, but polycystic ovary syndrome was developed. Whole-exome gene sequencing revealed a GCKR gene c. 69delG heterozygous mutation. After molecular diagnosis, the insulin dosage was gradually reduced to full cessation, and only metformin sustained-release tablets were taken to control blood glucose. It is necessary to regular evaluate islet function of patient with type 1 diabetes, and genetic test is of significance for accurate diagnosis and treatment.

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).

Clinical features and precision medicine of the six most common types of monogenic diabetes / 中华内分泌代谢杂志

Monogenic diabetes is a special type of diabetes caused by a single gene mutation, and it is commonly misdiagnosed in clinical practice. The two major forms of monogenic diabetes are neonatal diabetes(NDM) and maturity onset diabetes of the young(MODY). The most common mutations in 6 genes, induding HNF1α, GCK, HNF4α, KCNJ11, ABCC8, and INS, account for more than 90% of all monogenic diabetic cases. This article is to review recent advances in clinical features, and precision medicine of monogenic diabetes, and to discuss the significance of insights gained from monogenic diabetes in better understanding the pathogenesis of type 1 and type 2 diabetes. The current models for screening of monogenic diabetes were also discussed.

Application of next-generation sequencing in monogenic diabetes / 中国糖尿病杂志

[Summary] Next-generation sequencing is a revolution in the approach of genetic testing. It broadens the insight on the genetic diagnosis and research of monogenetic diabetes,which is represented by neonatal diabetes mellitus and maturity onset diabetes of the young.And it reveals advantages in exploring novel mutations.

Clinical Profile and Outcome of Infantile Onset Diabetes Mellitus in Southern India.

Objective: To study the etiology, clinical presentation and outcome of infantile onset diabetes mellitus (IODM). Design: Descriptive cohort study. Retrospective study from 1999- 2007 and prospective from 2008-2012. Setting: The diabetic clinic at a Pediatric tertiary care referral institute in Chennai. Methods: All infants diagnosed to have diabetes at less than one year of age were studied. Study variables were age at onset, gender, mode of presentation, birth weight, initial blood glucose, serum HbA1c, serum c–peptide levels, outcome at initial presentation, insulin requirement, associated co-morbid conditions, genetic analysis and outcome at the end of the study or until they were followed up. Results: 40 infants with infantile onset diabetes were studied, constituting 8% of all children with onset of DM at less than 12 years of age. 67.5% of these children presented with diabetic keto acidosis (DKA), only 30% had a provisional diagnosis of DM or DKA at first physician contact. 63% of IODM with onset less than 6 months and 30% with onset more than 6 months were of low birth weight. Nearly 85% of the study group had low C-peptide levels. 84.5% of IODM with onset less than 6 months and 55% of those with onset more than 6 months were monogenic. Wolcott Rallison syndrome was the commonest type encountered. Genetic diagnosis aided switching over from insulin to oral sulphonylurea in 5 children with KCNJ11 and ABCC8 mutations. Missed diagnosis, recurrent admissions for metabolic instability and developmental delay were common problems in IODM. Mortality at 12.5 year follow up was 32.5%. Conclusions: IODM with onset at less than 6 months is predominantly monogenic and low birth weight is more common. 55% of IODM were misdiagnosed at onset. Developmental delay is the common co morbid condition in IODM. Genetic diagnosis aids change of therapy to oral sulphonylurea.

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)

HNF1α mutations are present in half of clinically defined MODY patients in South-Brazilian individuals / Mutações HNF1α estão presentes na metade dos pacientes da região sul do Brasil clinicamente diagnosticados com MODY

Maturity-onset diabetes of the young (MODY) is a monogenic form of diabetes mellitus characterized by autosomal dominant inheritance, early age of onset, and pancreatic beta cell dysfunction. Heterozygous mutations in at least seven genes can cause MODY. In the present study we investigated the relative prevalence of GCK (glucokinase) and HNF1α (hepatocyte nuclear factor 1α) mutations, the more frequent causes of MODY, in 13 South-Brazilian families with multiple cases of diabetes consistent with MODY. Heterozygous variants in GCK and HNF1α genes were observed respectively in one (7.7 percent), and six (46.2 percent) families. The six HNF1α variants are likely to cause diabetes in the families where they were observed. However, we could not ascertain whether the GCK Gly117Ser variant found in one family is a causal mutation. In conclusion, we have confirmed in a South-Brazilian population that HNF1α mutations are a common cause of monogenic diabetes in adults selected with strict clinical diagnostic criteria.

O maturity-onset diabetes of the young (MODY) é uma forma monogênica de diabetes melito caracterizada por herança autossômica dominante, de instalação precoce, como disfunção da célula beta pancreática. Mutações heterozigotas em pelo menos sete genes causam MODY. No presente estudo, investigamos a prevalência relativa das mutações da GCK (glucokinase) e HNF1α (hepatocyte nuclear factor 1α), as causas mais freqüentes de MODY, em 13 famílias sul-brasileiras com múltiplos casos de diabetes consistentes com MODY. Variantes heterozigotas nos genes da GCK e HNF1α foram observadas, respectivamente, em uma (7,7 por cento) e em seis (46,2 por cento) famílias. As seis variantes do HNF1α provavelmente causaram o diabetes nas famílias nas quais foram observadas. No entanto, não se pode afirmar que a variante GCK Gly117Ser encontrada em uma família seja a mutação causal. Em conclusão, confirmamos que, em uma população do sul do Brasil, as mutações HNF1α são uma causa comum de diabetes monogênico em adultos selecionados com critérios clínicos diagnósticos estritos.