Felipe Crispim

Prevalence of vitamin D receptor gene polymorphisms FokI and BsmI in Brazilian individuals with type 1 diabetes and their relation to β-cell autoimmunity and to remaining β-cell function

The effect of the vitamin D receptor (VDR) gene polymorphisms on susceptibility to type 1 diabetes (T1DM) is heterogeneous. Genetic factors may also influence the residual beta-cell function. We studied the frequency of VDR FokI (rs10735810) and BsmI (rs154410) polymorphisms in T1DM and their relationship to beta-cell autoimmunity and residual beta-cell function. We genotyped 189 T1DM (diabetes duration, 7.1 +/- 5.4 years) and 194 controls (C) by restriction length polymorphism-polymerase chain reaction. GAD65Ab, IA2Ab, ionized calcium (iCa), HbA(1c)and fasting C-peptide (FCP) were evaluated. FCP values greater than 0.6 ng/ml were considered as residual beta-cell function. The BsmI was more frequent in the C (bb plus Bb 79.1 C vs. 66.1% T1DM, p = 0.006), and the FokI polymorphism frequencies were similar between T1DM and C. We did not observe differences in pancreatic autoantibody profiles according to VDR genotypes. We observed that T1DM with f allele tended to have lower residual pancreatic beta-cell function (5.8% ff and Ff vs. 14.3% FF, p = 0.074) with similar age, diabetes duration, AAb positivity, HbA(1c), and iCa. Age at diagnosis of T1DM with BsmI polymorphism tended to be greater (10.7 +/- 4.9 bb and Bb vs. 9.3 +/- 4.5 years BB, p = 0.06). In conclusion, the results of this study showed no relationship between VDR polymorphisms and beta-cell autoimmunity; however we observed a relationship with age and remaining beta-cell function in Brazilian individuals with T1DM. These data may contribute to understanding the heterogeneous relationship between genetic markers and clinical features observed in this disease.

Phenotypic diversity in patients with lipodystrophy associated with LMNA mutations

OBJECTIVE Mutations in LMNA have been linked to diverse disorders called laminopathies, which display heterogeneous phenotypes and include diseases affecting muscles, axonal neurons, progeroid syndromes, and lipodystrophies. Among the lipodystrophies, LMNA mutations have been reported most frequently in patients with familial partial lipodystrophy (FPLD) of the Dunnigan variety; however, phenotypic heterogeneity in the pattern of body fat loss has been observed. In this study, we searched for LMNA mutations in patients with various forms of lipodystrophy. DESIGN AND METHODS We studied 21 unrelated individuals with lipodystrophy. Subjects underwent a complete clinical evaluation and were classified as typical FPLD (n=12), atypical partial lipodystrophy (n=7), or generalized lipodystrophy (n=2). Molecular analysis of LMNA gene, analysis of body fat by dual-energy X-ray absorptiometry, and biochemical measurements were performed. RESULTS ALL PATIENTS WITH TYPICAL FPLD WERE FOUND TO CARRY LMNA MUTATIONS: seven patients harbored the heterozygous p.R482W (c.1444C>T), two patients harbored the p.R482Q (c.1445G>A), and two individuals harbored the novel heterozygous variant p.N466D (c.1396A>G), all in exon 8. Also, a homozygous p.R584H (c.1751 G>A) mutation in exon 11 was found. Among patients with atypical partial lipodystrophy, two of them were found to have LMNA mutations: a novel heterozygous p.R582C variation (c.1744 C>T) in exon 11 and a heterozygous substitution p.R349W (c.1045C>T) in exon 6. Among patients with generalized lipodystrophy, only one harbored LMNA mutation, a heterozygous p.T10I (c.29C>T) in exon 1. CONCLUSIONS We have identified LMNA mutations in phenotypically diverse lipodystrophies. Also, our study broadens the spectrum of LMNA mutations in lipodystrophy.

Sulfonylrea Treatment in Permanent Neonatal Diabetes Due to G53D Mutation in the KCNJ11 Gene Improvement in glycemic control and neurological function

Previous studies have reported the successful switch from insulin to sulfonylrea therapy in some patients who have neonatal diabetes due to KCNJ11 mutations (1); however, data on adults are limited (2,3). Also, it has not yet been determined whether neurological symptoms can be improved by the action of sulfonylrea therapy. Here, we report the glycemic and neurological responses in an adult patient with the G53D mutation in the KCNJ11 gene who was transferred from insulin to sulfonylurea. A 26-year-old male patient was diagnosed with diabetes in the third month of …

Identification of novel mutations of the WFS1 gene in Brazilian patients with Wolfram syndrome

OBJECTIVE Wolfram syndrome (WS) is a rare, progressive, neurodegenerative disorder with an autosomal recessive pattern of inheritance. The gene for WS, WFS1, was identified on chromosome 4p16 and most WS patients carry mutations in this gene. However, some studies have provided evidence for genetic heterogeneity and the genotype-phenotype relationships are not clear. Our aim was to ascertain the spectrum of WFS1 mutations in Brazilian patients with WS and to examine the phenotype-genotype relationships in these patients. DESIGN AND METHODS Clinical characterization and analyses of the WFS1 gene were performed in 27 Brazilian patients with WS from 19 families. RESULTS We identified 15 different mutations in the WFS1 gene in 26 patients, among which nine are novel. All mutations occurred in exon 8, except for one missense mutation which was located in exon 5. Although we did not find any clear phenotype-genotype relationship in patients with mutations in exon 8, the homozygous missense mutation in exon 5 was associated with a mild phenotype: onset of diabetes mellitus and optic atrophy during adulthood with good metabolic control being achieved with low doses of sulfonylurea. CONCLUSIONS Our data show that WFS1 is the major gene involved in WS in Brazilian patients and most mutations are concentrated in exon 8. Also, our study increases the spectrum of WFS1 mutations. Although no clear phenotype-genotype relationship was found for mutations in exon 8, a mild phenotype was associated with a homozygous missense mutation in exon 5.

Diagnóstico de metástases de carcinoma papilífero de tiróide através da dosagem de tiroglobulina no líquido obtido da lavagem da agulha utilizada na punção aspirativa

The widespread use of neck ultrasonography (US) during the follow-up of patients with papillary thyroid carcinoma (PTC) has led to the discovery of small cervical lymph nodes (LN). Although US has a high sensitivity for diagnosing LN, fine needle aspiration biopsy (FNA) and measurement of thyroglobulin in fine needle aspirates (FNA-Tg) have proven to be invaluable tools. The aim of this study is to determine the sensitivity of the combined use of neck US, FNA biopsy and FNA-Tg for diagnosis of cervical lymph nodes. We have studied 32 patients with 44 LN detected by US, 19 classified as inflammatory and 25 as suspicious. 15 of those 25 suspicious LN had high FNA-Tg (13 of the 15 had positive cytology and 2 indeterminate). All of these 15 LN (11 patients) were proven to be PTC metastasis by histopathology. All 19 inflammatory LN and those 10/25 suspicious LN, had cytology negative for malignancy and undetectable FNA-Tg. We conclude that fine needle aspiration biopsy and FNA-Tg combined with neck US are essential for detecting positive cervical lymph nodes due to its high sensitivity and specificity and it should be considered the standard for investigating locally recurrent disease in patients with PTC.

Association of ADIPOQ variants, total and high molecular weight adiponectin levels with coronary artery disease in diabetic and non-diabetic Brazilian subjects

OBJECTIVE To investigate the association of ADIPOQ variants, total and high molecular weight adiponectin (HMW) adiponectin levels with the prevalence of diabetes mellitus and coronary artery disease (CAD) diagnosed by coronary angiography in Brazilian subjects with high cardiovascular risk. METHODS 603 subjects undergoing coronary angiography were studied in regard to their glycemic status and presence of CAD (lesions >0%). We evaluated baseline concentrations of total and HMW adiponectin and three ADIPOQ variants: -11391G>A (rs17300539), +45T>G (rs2241766) and+276G>T (rs1501299). RESULTS The G-allele of rs2241766 was associated with higher levels of total and HMW adiponectin, and the A-allele of rs17300539 was associated with higher levels of HMW adiponectin. Lower levels of total and HMW adiponectin were independently associated with CAD. The G-allele of rs2241766 (OR 2.45, 95% C.I. 1.05-6.04, p=0.04) and the G-allele of rs1501299 (OR 1.89, 95% C.I. 1.04-3.45, p=0.03) were associated with CAD, and these associations were independent of circulating levels of adiponectin. CONCLUSIONS In Brazilian subjects with high cardiovascular risk, CAD was associated with lower total and HMW adiponectin levels. The rs2241766 and rs1501299 polymorphisms were associated with CAD. The rs2241766 variant was associated with total and HMW adiponectin levels, while rs17300539 was associated with HMW adiponectin levels.

ADIPOQ and adiponectin: the common ground of hyperglycemia and coronary artery disease?

Plasma adiponectin and the coding gene for adiponectin, ADIPOQ, are thought to explain part of the interaction between obesity, insulin resistance, type 2 diabetes (T2DM) and coronary artery disease (CAD). Here, we illustrate the role that adiponectin and ADIPOQ variants might play in the modulation of CAD, especially in the occurrence of hyperglycemia. Recent evidence suggests that total and high molecular weight (HMW) adiponectin levels are apparent markers of better cardiovascular prognosis in patients with low risk of CAD. However, in subjects with established or high risk of CAD, these levels are associated with poorer prognosis. We also provide recent evidences relating to the genetic control of total and HMW adiponectin levels, especially evidence regarding ADIPOQ. Accumulated data suggest that both adiponectin levels and polymorphisms in the ADIPOQ gene are linked to the risk of CAD in patients with hyperglycemia, and that these associations seem to be independent from each other, even if adiponectin levels are partly dependent on ADIPOQ.

Atypical generalized lipoatrophy and severe insulin resistance due to a heterozygous LMNA p.T10I mutation

Lipodystrophies are a group of heterogeneous disorders characterized by the loss of adipose tissue and metabolic complications. The main familial forms of lipodystrophy are Congenital Generalized Lipodystrophy and Familial Partial Lipodystrophy (FPLD). FPLD may result from mutations in the LMNA gene. Besides FPLD, mutations in LMNA have been shown to be responsible for other inherited diseases called laminopathies. Here we describe the case of a 15-year-old girl who was referred to our service due to diabetes mellitus and severe hypertriglyceridemia. Physical examination revealed generalized loss of subcutaneous fat, confirmed by DEXA (total body fat 8.6%). As the patient presented with pubertal-onset of generalized lipodystrophy and insulin resistance, molecular analysis of the LMNA gene was performed. We identified a heterozygous substitution in exon 1 (c.29C>T) predicting a p.T10I mutation. In summary, we describe an atypical phenotype of lipodistrophy associated with a de novo appearance of the p.T10I mutation in LMNA gene.

Basal serum thyroglobulin measured by a second-generation assay is equivalent to stimulated thyroglobulin in identifying metastases in patients with differentiated thyroid cancer with low or intermediate risk of recurrence.

Background: Guidelines for the follow-up of differentiated thyroid cancer (DTC) recommend the measurement of TSH-stimulated thyroglobulin (s-Tg) instead of basal Tg on T4 therapy (b-Tg). However, these guidelines were established using first-generation Tg assays with a functional sensitivity (FS) of 0.5-1.0 ng/ml. Current more sensitive second-generation Tg assays (Tg2G; FS 0.05-0.10 ng/ml) have shown that low-risk DTC patients with undetectable b-Tg rarely have recurrences. Objectives: This study was undertaken to compare b-Tg using a chemiluminescent Tg2G assay (Tg2GICMA; FS 0.1 ng/ml) with s-Tg in DTC patients with an intermediate risk of recurrence. Methods: We evaluated 168 DTC patients with a low (n = 101) and intermediate (n = 67) risk of recurrence treated by total thyroidectomy (147 also treated with radioiodine), with a mean follow-up of 5 years. Results: b-Tg was undetectable with the Tg2GICMA in 142 of 168 patients. s-Tg was <2 ng/ml in 138 of these 142 patients, and only 3 of these 138 (2%) presented metastases on cervical ultrasound (US). Of the 4 of 142 patients with s-Tg >2 ng/ml, 1 had cervical metastases seen after radioiodine. Furthermore, 26 of 168 patients presented detectable b-Tg with the Tg2GICMA; 17 of these 26 patients also presented s-Tg >2 ng/ml. In 10 of these 17 patients, metastases were detected. Cervical US or b-Tg were positive in 14 of 15 patients with recurrent disease. Globally, the sensitivity and negative predictive value of the Tg2GICMA plus US were 93 and 99%, respectively. Conclusion: b-Tg measured with a Tg2GICMA and cervical US, used together, are equivalent to s-Tg in identifying metastases in patients with DTC with a low or intermediate risk of recurrence.

Síndrome de Wolfram: da definição às bases moleculares

Wolfram syndrome (WS) is an autosomal recessive progressive neurodegenerative disorder characterized by diabetes mellitus and optic atrophy. Diabetes insipidus and sensorineural deafness are also noted frequently, explaining the acronym DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy and deafness) by which the syndrome is also referred. Additional manifestations such as atonic bladder, ataxia, nystagmus and predisposition for psychiatric illness may be present. The Wolfram syndrome gene, WFS1, was mapped to chromosome 4p16.1 by positional cloning. It encodes an 890-amino-acid polypeptide named wolframin. Although the wolframin function is still not completely known, its localization to the endoplasmic reticulum suggests it can play a role in calcium homeostasis, membrane trafficking and protein processing. Knowing the cellular function of wolframin is necessary for understanding the pathophysiology of Wolfram syndrome. This knowledge may lead to development of therapies to prevent or reduce the outcomes of WS.