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).

Detección de mutaciones del gen de HNF1B en niños con malformaciones congénitas renales y del tracto urinario / Detection of mutations of the HNF1B gene in children with congenital anomalies of the kidney and urinary tract

Resumen: Introducción: Las anomalías congénitas del riñón y del tracto urinario se originan de alteraciones genéticas, en su mayoría desconocidas. Las mutaciones en el gen que codifica para el factor hepatocitario nuclear 1B (HNF1B), son la causa monogénica más frecuentemente descrita. Se desconocen datos en Chile y Latinoamérica. Objetivo: Determinar la presencia de variantes del gen HNF1B en niños chilenos con anomalías congénitas del riñón y/o tracto urinario y sus características clínicas. Pacientes y Mé todo: Estudio descriptivo con pacientes entre 10 meses y 17 años, consultantes en Unidad de Nefrología Hospital Luis Calvo Mackenna, período abril - diciembre 2016, portadores de displasia renal quística, displasia/hipoplasia renal no quística y/o riñón en herradura. Se determinaron variantes de HNF1B mediante secuenciación de exones 1, 2, 3 y 4; previa extracción y amplificación de DNA. Se utilizaron enzimas de restricción para definir si variantes eran homo o heterocigotas. Familiares di rectos de casos índices se estudiaron con secuenciación del exón afectado. Resultados: Se incluyeron 32 pacientes, 43,75% varones, mediana edad 11 años. El 65,6% displasia/hipoplasia renal no quística, 31,25% displasia renal quística y 3,15% riñón en herradura. En 2 pacientes (6,25%) se detectó una misma variante genética heterocigota en exón 4, posición 1027 (C1027T), no descrita anteriormente. El estudio de familiares determinó la variante en 3 de 5 individuos, todos sin anomalías nefrouro- lógicas congénitas. Conclusiones: Confirmamos la presencia de una variante genética heterocigota del gen HNF1B, no descrita previamente, dando inicio a la búsqueda de este tipo de mutaciones en nuestro medio, lo cual nos permite aproximarnos al conocimiento de causalidad, determinación de compromiso extrarrenal y consejo genético.

Abstract Introduction: Congenital anomalies of the kidney and urinary tract are caused by genetic alterations mostly unknown. Mutations in the gene that codes for hepatocyte nuclear factor 1B (HNF1B) are the most frequently described monogenic causes. Data are unknown in Chile and Latin America. Objective: To determine the presence of variants of the HNF1B gene in Chilean children with conge nital anomalies of the kidney and/or the urinary tract and their clinical characteristics. Patients and Method: Descriptive study with children aged 10 months to 17 years, patients of the Calvo Mackenna Hospital Nephrology Unit, with cystic renal dysplasia, non cystic renal dysplasia/hypoplasia, horses hoe kidney between April and December 2016. HNF1B variants were determined by sequencing of exons 1, 2, 3 and 4 after DNA extraction and amplification. Restriction enzymes were used to define if the variants were homo or heterozygous. Direct family members of index cases were studied with sequencing of the affected exon. Results: 32 patients were included, 43.75% males, median age 11 years. 65.6% of them had non-cystic renal dysplasia, 31.25% cystic renal dysplasia, and 3.15% hor seshoe kidney. In two patients (6.25%) the same heterozygous genetic variant was detected in exon 4, position 1027 (C1027T), not previously described. The study of relatives found the same variant in three out of five individuals, all without congenital nephro-urological anomalies. Conclusions: We confirmed the presence of a not previously described heterozygous genetic variant of the HNF1B gene. This work initiates the search for this type of mutations in our region which allows us to ap proach the knowledge of causality, determination of extrarenal involvement, and genetic counseling.

The rs4430796 SNP of the HNF1ß gene associates with type 2 diabetes in older adults

SUMMARY INTRODUCTION: The impact of type 2 diabetes mellitus raises interest in understanding its evolutionary-genetic basis, to unveil yet unknown pathways that may have immediate medical relevance. The HNF1β gene (hepatocyte nuclear factor-1 beta) is a transcription factor expressed in tissues such as liver, kidney, genital tract and pancreas that is known to be essential for insulin secretion and glucose balance. We tested the association of allelic variants produced by the HNF1β gene (rs4430796) variation with the clinical and biochemical profile of elderly Brazilian outpatients with metabolic disorders. MATERIAL AND METHODS: Anthropometry, blood pressure, glycaemia, lipemia and other parameters were assessed in 184 Brazilians aged 60 or older in clinical care settings. Alleles were determined by amplification of the polymorphic site by real time polymerase chain reaction. RESULTS: Analysing variables across the genotypes, a statistically significant difference was noticed in the allele frequencies among diabetic patients, with 30.8% of the A homozygous bearing the condition compared to a prevalence of 12.2% between G homozygotes. CONCLUSION: Our results corroborate the possible protective property of the GG genotype from the rs4430796 variation (already presented in the literature) against occurrence of diabetes mellitus, which appears applicable to elderly individuals as well, even in the context of multiple metabolic disorders so typical in older Brazilians.

Presentaciones poco frecuentes de diabetes tipo MODY: el ejemplo de MODY tipo 5 y las formas de novo de MODY tipo 2 / Infrequent presentations of MODY diabetes: the example of MODY type 5 and de novo forms of MODY type 2

La diabetes tipo MODY se produce por alteraciones en genes relacionados con el metabolismo de la célula beta pancreática. El tipo 2 es uno de los más frecuentes y se produce por alteraciones en el gen GCK (glucoquinasa) y el tipo 5 es mucho menos frecuente y se produce por alteraciones en el gen HNF1B (factor nuclear hepático 1B). Se presentan con herencia autosómica dominante, aunque se ha descripto la presencia de mutaciones de novo. El objetivo del trabajo fue buscar mutaciones en el gen GCK en pacientes sin antecedentes familiares pero con características clínicas de MODY2 y mutaciones en el gen HNF1B en pacientes con características clínicas de MODY5 con y sin antecedentes familiares. Para ello a partir de ADN se realizó la secuenciación de cada gen por el método de Sanger o por secuenciación de nueva generación. Como resultado, se hallaron mutaciones en el gen GCK en cuatro pacientes sin antecedentes familiares y mutaciones en el gen del HNF1B en dos pacientes, uno de ellos sin antecedentes familiares. Como conclusión puede afirmarse que las mutaciones de novo en el gen de la GCK son más frecuentes de lo descripto, por lo cual se recomienda el estudio del gen en pacientes con características compatibles aún sin antecedentes familiares. También es importante el estudio del gen HNF1B en pacientes con características típicas ya que deben tratarse no sólo por sus alteraciones renales sino por la diabetes presente; de esta manera se logra un correcto diagnóstico para instaurar el tratamiento más adecuado

Effects of grape powder supplementation on inflammatory and antioxidant markers in hemodialysis patients: A randomized double-blind study / Efeitos da suplementação de farinha de uva sobre marcadores inflamatórios e antioxidantes em pacientes em hemodiálise: Estudo duplo-cego randomizado

Introduction: Polyphenols contained in natural sources such as grapes, have been considered pharmacological agents to combat oxidative stress and inflammation, common features in Chronic Kidney Disease patients. Objective: To evaluate the effects of grape powder supplementation on inflammatory and antioxidant biomarkers in hemodialysis (HD) patients. Methods: The double-blind placebo-controlled randomized clinical trial evaluated non-diabetic HD patients that received grape powder (500 mg of polyphenols/day) (n = 16, 9 men, 53.0 ± 9.8 years of age, 111.6 ± 58.2 HD months) or placebo (n = 16, 9 men, 52.7 ± 13.7 years of age, 110.4 ± 93.1 HD months) for five weeks. The glutathione peroxidase (GSH-Px) activity and C-reactive protein (CRP) levels were evaluated by ELISA method. Results: After the intervention period, the patients receiving grape powder showed an increase in the GSH-Px activity (16.5 (41.0) to 42.0 (43.3) nmol/min/ml) (p < 0.05) and they did not have the CRP levels increased as seen in placebo group (2.6 (0.28) to 2.8 (0.23 mg/L) (p < 0.05). Conclusion: The use of grape powder as phenolic source could play an important role as an antioxidant and anti-inflammatory agent in non-diabetic HD patients. .

Introdução: Polifenóis contidos em fontes naturais, como as uvas, têm sido considerados agentes farmacológicos no combate ao estresse oxidativo e inflamação, condições comuns na Doença Renal Crônica. Objetivo: Avaliar os efeitos da suplementação de farinha de uva sobre marcadores inflamatórios e antioxidantes em pacientes submetidos à hemodiálise (HD). Métodos: Estudo randomizado, duplo-cego, placebocontrolado, no qual foram avaliados pacientes não diabéticos em HD que receberam farinha de uva (500 mg de polifenóis/dia) (n = 16, 9 homens, 53,0 ± 9,8 anos, 111,6 ± 58,2 meses em HD) ou placebo (n = 16, 9 homens, 52,7 ± 13,7 anos, 110,4 ± 93,1 meses em HD) por cinco semanas. A atividade da glutationa peroxidase (GSH-Px) e os níveis plasmáticos de proteína C-reativa (PCR) foram mensurados por meio do método ELISA. Resultados: Após o período de intervenção, os pacientes que receberam farinha de uva apresentaram elevação na atividade da GSH-Px (16,5 (41,0) para 42,0 (43,3) nmol/min/ml) (p < 0,05) e não foi observada elevação nos níveis de PCR, como visto no grupo placebo (2,6 (0,28) para 2,8 (0,23) mg/L) (p < 0,05). Conclusão: O uso da farinha de uva como fonte de polifenóis pode desempenhar um importante papel anti-inflamatório e antioxidante em pacientes não diabéticos submetidos à HD. .