Juvenile hemochromatosis: HAMP mutation and severe iron overload treated with phlebotomies and deferasirox.

Juvenile hemochromatosis (JH) is a rare condition classified as an autosomal recessive disorder that leads to severe iron absorption. JH usually affects people under the age of 30 and presents symptoms such as chronic liver damage, hypogonadotropic hypogonadism, cardiac diseases and endocrine dysfunctions. The present case reports a 29-year-old Brazilian woman with JH condition due to HAMP mutation (g.47G>A), treated with phlebotomies and deferasirox. She presented symptoms such as weakness, skin hyperpigmentation, joint pain in the shoulders and hands and amenorrhea. First laboratory tests showed altered biochemical parameters [serum ferritin (SF): 5696 ng/mL, transferrin saturation (TS): 85%]. After sessions of phlebotomies (450 mL every 15 d), the patient presented partial symptomatic improvements and biochemical parameters (SF: 1000 ng/mL, Hb: 11 g/dL). One year later, deferasirox (15 mg/kg per day) was introduced to the treatment, and the patient showed total symptomatic improvement, with significant clearing of the skin, SF: 169 ng/mL, and TS: 50%. Furthermore, after the combined deferasirox-phlebotomy therapy, magnetic resonance imaging measurements revealed normalized level for liver iron (30 µmol/g; reference value < 36 µmol/g). In conclusion, combined deferasirox-phlebotomy treatment was able to normalize iron levels and improve symptoms.

CHRNA4 rs1044396 is associated with smoking cessation in varenicline therapy.

BACKGROUND: The large individual variability in response to drugs for smoking cessation suggests that specific treatments can be more effective in particular subgroups of smokers. In the context of personalized medicine, the main aim of the present study was to evaluate whether the CHRNA4 and CHRNB2 polymorphisms are associated with response to smoking cessation therapies in patients from a smoker assistance program. METHODS: This cohort study enrolled 483 smoking patients who received behavioral counseling and drug treatment (varenicline, bupropion, and/or nicotine replacement therapy). Smoking cessation success was considered for patients who completed 6 months of continuous abstinence. Fagerström test for nicotine dependence (FTND) and Issa situational smoking scores were analyzed for nicotine dependence. The CHRNA4 (rs1044396 and rs2236196) and CHRNB2 (rs2072660 and rs2072661) polymorphisms were genotyped by high resolution melting analysis. RESULTS: Patients with rs1044396 CC genotype had lower success rate in treatment with varenicline (29.5%) compared with carriers of CT or TT genotypes (50.9%; p = 0.007, n = 167). The CT or TT genotypes were associated with higher odds ratio for success (OR = 1.67, 95% CI = 1.10-2.53, p = 0.02), in a multivariate model. We did not observe significant differences in the FTND and Issa scores according to the studied polymorphisms. CONCLUSION: The CHRNA4 rs1044396 is associated with smoking cessation in individuals on varenicline therapy. We suggest that this polymorphism influences the varenicline response, but replications of this finding are needed.

General aspects of muscle glucose uptake.

Glucose uptake in peripheral tissues is dependent on the translocation of GLUT4 glucose transporters to the plasma membrane. Studies have shown the existence of two major signaling pathways that lead to the translocation of GLUT4. The first, and widely investigated, is the insulin activated signaling pathway through insulin receptor substrate-1 and phosphatidylinositol 3-kinase. The second is the insulin-independent signaling pathway, which is activated by contractions. Individuals with type 2 diabetes mellitus have reduced insulin-stimulated glucose uptake in skeletal muscle due to the phenomenon of insulin resistance. However, those individuals have normal glucose uptake during exercise. In this context, physical exercise is one of the most important interventions that stimulates glucose uptake by insulin-independent pathways, and the main molecules involved are adenosine monophosphate-activated protein kinase, nitric oxide, bradykinin, AKT, reactive oxygen species and calcium. In this review, our main aims were to highlight the different glucose uptake pathways and to report the effects of physical exercise, diet and drugs on their functioning. Lastly, with the better understanding of these pathways, it would be possible to assess, exactly and molecularly, the importance of physical exercise and diet on glucose homeostasis. Furthermore, it would be possible to assess the action of drugs that might optimize glucose uptake and consequently be an important step in controlling the blood glucose levels in diabetic patients, in addition to being important to clarify some pathways that justify the development of drugs capable of mimicking the contraction pathway.

Deferasirox in patients with iron overload secondary to hereditary hemochromatosis: results of a 1-yr Phase 2 study.

This open-label, prospective, phase 2 study evaluated the safety and efficacy of deferasirox (10 ± 5 mg/kg/d) in patients with hereditary hemochromatosis (HH) and iron overload refractory to or intolerant of phlebotomy. Ten patients were enrolled and all completed the 12-month treatment period. There were significant decreases from baseline to end of study (i.e., 12 months) in median serum ferritin (P < 0.001), mean transferrin saturation (P < 0.05), median liver iron concentration (P < 0.001), and mean alanine aminotransferase (P < 0.05). The median time to achieve serum ferritin reduction ≥50% compared to baseline was 7.53 months. The most common adverse events were mild, transient diarrhea (n = 5) and nausea (n = 2). No patient experienced an increase in serum creatinine that exceeded the upper limit of normal. These data confirm that deferasirox was well tolerated and effective in reducing iron burden in patients with hereditary hemochromatosis and could be a safe alternative to phlebotomy in selected patients.

The MYLIP p.N342S polymorphism is associated with response to lipid-lowering therapy in Brazilian patients with familial hypercholesterolemia.

BACKGROUND: A previous study reported that the myosin regulatory light chain interacting protein (MYLIP) might serve as a novel therapeutic class for treating dyslipidemia. It contributes to variations in the levels of circulating low-density lipoprotein cholesterol (LDL-C), promoting the degradation of LDL-LDLR, thus limiting absorption. The effect of genetic variation in the MYLIP gene in a disease scenario characterized by mutations in the LDLR gene has not been previously evaluated. OBJECTIVE: The aim of this study was to assess the effect of the p.N342S variant on the response to lipid-lowering therapy in Brazilian patients with heterozygous familial hypercholesterolemia (FH). PATIENTS AND METHODS: A total of 156 patients with heterozygous FH were followed up for 12 months and received lipid-lowering therapy (different doses of atorvastatin with the addition of ezetimibe in over half the patients of each genotype group). Cholesterol data were assessed, and analysis of the MYLIP rs9370867 (p.N342S) genotypes was carried out by melting curve analysis. RESULTS: Baseline total cholesterol and baseline LDL-C levels were not different between genotypes. After 1 year of treatment, LDL-C responses (expressed as mg/dl and as %) were significantly different among genotypes (AA: -79±68 and -39±27, GA: -60±79 and -27±32, and GG: -30±83 and -15±38; P=0.02 and 0.005, respectively). In addition, FH patients carrying the AA genotype were more likely to achieve LDL-C levels of less than 130 mg/dl after 1 year of treatment (75.0%) compared with patients with the GG and GA genotypes (34.5 and 34.8%, respectively; P=0.001). CONCLUSION: Our study indicates that MYLIP p.N342S might be a pharmacogenetic marker for lipid-lowering therapy in patients with FH.

Effectiveness of coadministration of varenicline, bupropion, and serotonin reuptake inhibitors in a smoking cessation program in the real-life setting.

INTRODUCTION: Varenicline has a significant impact on the ability to quit smoking. However, patients may have side effects similar to nicotine withdrawal symptoms. The aim of this study was to evaluate the effectiveness of varenicline in monotherapy or in combined therapy with bupropion and/or serotonin reuptake inhibitors (SRIs) in a specific cardiovascular smoking cessation service. METHODS: It is an outcome research of 427 patients that received varenicline monotherapy or combined pharmacotherapy and were followed for 52 weeks. Patients were oriented to take varenicline until week 12. During each medical visit, the patients were evaluated and in the cases of mood changes after varenicline use, SRIs were prescribed. Bupropion was combined in patients that did not achieve complete tobacco abstinence in 2 or 3 weeks after starting varenicline use or if the patient presented uncomfortable abstinent symptoms. RESULTS: The success (continuous abstinence rate in 52 weeks) in different drug regimens were: varenicline monotherapy (32.1%), varenicline + bupropion (55.0%), varenicline + SRI (50.6%), and varenicline + bupropion + SRI (57.7%). In a multivariate analysis of successful treatment predictors, compared with varenicline monotherapy, patients who used bupropion + SRI adjuvant treatment had an odds ratio (OR) of 5.05 (1.99-12.80) for a successful treatment response after 1-year follow-up, while patients who used bupropion or SRI had OR of 3.21 (1.68-6.14) and 3.58 (1.98-6.48), respectively. CONCLUSIONS: Our results suggest that adjuvant treatment to varenicline therapy may be associated with improved success in smoking cessation, especially in patients with nicotine withdrawal symptoms. These results should be tested in randomized controlled trials.

SLCO1B1 rs4149056 polymorphism associated with statin-induced myopathy is differently distributed according to ethnicity in the Brazilian general population: Amerindians as a high risk ethnic group.

BACKGROUND: Recent studies reported the association between SLCO1B1 polymorphisms and the development of statin-induced myopathy. In the scenario of the Brazilian population, being one of the most heterogeneous in the world, the main aim here was to evaluate SLCO1B1 polymorphisms according to ethnic groups as an initial step for future pharmacogenetic studies. METHODS: One hundred and eighty-two Amerindians plus 1,032 subjects from the general urban population were included. Genotypes for the SLCO1B1 rs4149056 (c.T521C, p.V174A, exon 5) and SLCO1B1 rs4363657 (g.T89595C, intron 11) polymorphisms were detected by polymerase chain reaction followed by high resolution melting analysis with the Rotor Gene 6000® instrument. RESULTS: The frequencies of the SLCO1B1 rs4149056 and rs4363657 C variant allele were higher in Amerindians (28.3% and 26.1%) and were lower in African descent subjects (5.7% and 10.8%) compared with Mulatto (14.9% and 18.2%) and Caucasian descent (14.8% and 15.4%) ethnic groups (p<0.001 and p<0.001, respectively). Linkage disequilibrium analysis show that these variant alleles are in different linkage disequilibrium patterns depending on the ethnic origin. CONCLUSION: Our findings indicate interethnic differences for the SLCO1B1 rs4149056 C risk allele frequency among Brazilians. These data will be useful in the development of effective programs for stratifying individuals regarding adherence, efficacy and choice of statin-type.

Hereditary hemochromatosis: mutations in genes involved in iron homeostasis in Brazilian patients.

BACKGROUND: p.C282Y mutation and rare variants in the HFE gene have been associated with hereditary hemochromatosis (HH). HH is also caused by mutations in other genes, such as the hemojuvelin (HJV), hepcidin (HAMP), transferrin receptor 2 (TFR2) and ferroportin (SLC40A1). The low rate homozygous p.C282Y mutation in Brazil is suggestive that mutations in non-HFE genes may be linked to HH phenotype. AIM: To screen exon-by-exon DNA sequences of HFE, HJV, HAMP, TFR2 and SLC40A1 genes to characterize the molecular basis of HH in a sample of the Brazilian population. MATERIALS AND METHODS: Fifty-one patients with primary iron overload (transferrin saturation ≥50% in females and ≥60% in males) were selected. Subsequent bidirectional DNA sequencing of HFE, HJV, HAMP, TFR2 and SLC40A1 exons was performed. RESULTS: Thirty-seven (72.5%) out of the 51 patients presented at least one HFE mutation. The most frequent genotype associated with HH was the homozygous p.C282Y mutation (n=11, 21.6%). In addition, heterozygous HFE p.S65C mutation was found in combination with p.H63D in two patients and homozygous HFE p.H63D was found in two patients as well. Sequencing in the HJV and HAMP genes revealed HJV p.E302K, HJV p.A310G, HJV p.G320V and HAMP p.R59G alterations. Molecular and clinical diagnosis of juvenile hemochromatosis (homozygous form for the HJV p.G320V) was described for the first time in Brazil. Three TFR2 polymorphisms (p.A75V, p.A617A and p.R752H) and six SLC40A1 polymorphisms (rs13008848, rs11568351, rs11568345, rs11568344, rs2304704, rs11568346) and the novel mutation SLC40A1 p.G204S were also found. CONCLUSIONS: The HFE p.C282Y in homozygosity or in heterozygosity with p.H63D was the most frequent mutation associated with HH in this sample. The HJV p.E302K and HAMP p.R59G variants, and the novel SLC40A1 p.G204S mutation may also be linked to primary iron overload but their role in the pathophysiology of HH remain to be elucidated.

HFE gene mutations in patients with primary iron overload: is there a significant improvement in molecular diagnosis yield with HFE sequencing?

Rare HFE variants have been shown to be associated with hereditary hemochromatosis (HH), an iron overload disease. The low frequency of the HFE p.C282Y mutation in HH-affected Brazilian patients may suggest that other HFE-related mutations may also be implicated in the pathogenesis of HH in this population. The main aim was to screen for new HFE mutations in Brazilian individuals with primary iron overload and to investigate their relationship with HH. Fifty Brazilian patients with primary iron overload (transferrin saturation>50% in females and 60% in males) were selected. Subsequent bidirectional sequencing for each HFE exon was performed. The effect of HFE mutations on protein structure were analyzed by molecular dynamics simulation and free binding energy calculations. p.C282Y in homozygosis or in heterozygosis with p.H63D were the most frequent genotypic combinations associated with HH in our sample population (present in 17 individuals, 34%). Thirty-six (72.0%) out of the 50 individuals presented at least one HFE mutation. The most frequent genotype associated with HH was the homozygous p.C282Y mutation (n=11, 22.0%). One novel mutation (p.V256I) was indentified in heterozygosis with the p.H63D mutation. In silico modeling analysis of protein behavior indicated that the p.V256I mutation does not reduce the binding affinity between HFE and ß2-microglobulin (ß2M) in the same way the p.C282Y mutation does compared with the native HFE protein. In conclusion, screening of HFE through direct sequencing, as compared to p.C282Y/p.H63D genotyping, was not able to increase the molecular diagnosis yield of HH. The novel p.V256I mutation could not be implicated in the molecular basis of the HH phenotype, although its role cannot be completely excluded in HH-phenotype development. Our molecular modeling analysis can help in the analysis of novel, previously undescribed, HFE mutations.

Alterações moleculares associadas à hemocromatose hereditária / Molecular changes associated with hereditary hemochromatosis

A hemocromatose hereditária (HH) é a mais comum doença autossômica em caucasianos e caracteriza-se pelo aumento da absorção intestinal de ferro, o qual resulta em acúmulo progressivo de ferro no organismo. A classificação da HH é realizada de acordo com a alteração genética encontrada, sendo os casos divididos em tipos 1, 2A, 2B, 3 e 4, quando a sobrecarga de ferro for associada aos genes HFE, HJV, HAMP, TFR2 e SLC40A1, respectivamente. Não existem estudos brasileiros que avaliaram a presença de mutações em genes relacionados à fisiopatologia da HH (genes HJV, HAMP, TFR2 e SLC40A1), além da pesquisa das três mutações no gene HFE (C282Y, H63D e S65C). Porém, está descrito, nos estudos realizados no Brasil, que alguns pacientes com sobrecarga de ferro primária não são portadores da HH tipo 1 (associada ao gene HFE). Portanto, é de suma importância a identificação das características genéticas dessa população, uma vez que outras mutações nos genes HJV, HAMP, TFR2 e SLC40A1 podem estar associadas à fisiopatologia da doença, podendo haver interações entre os genes alterados, de forma que possa auxiliar no entendimento da fisiopatologia da HH em pacientes brasileiros.

Hereditary Hemochromatosis (HH) is the most common autosomal disease in Caucasians. It is characterized by an increase in intestinal absorption of iron, which results in a progressive accumulation of iron in the body. The classification of HH is carried out according to the genetic alteration found; thus cases of HH are divided into Types 1, 2A, 2B, 3 and 4, when the iron overload is associated to the HFE, HJV, HAMP, TFR2 and SLC40A1 genes, respectively. There is research on the three HFE gene mutations (C282Y, H63D and S65C) in the Brazilian population however there are no Brazilian studies that evaluate the presence of mutations in other genes related to the pathophysiology of HH (HJV, HAMP, TFR2 and SLC40A1 genes). Nevertheless, studies conducted in Brazil have described that some patients with primary iron overload are not carriers of the Type 1 HH (associated with the HFE gene). Hence, it is very important to identify the genetic characteristics of this population, as mutations of the HJV, HAMP, TFR2 and SLC40A1 genes may be associated with the pathophysiology of the disease, and there may be interactions between mutations. These findings will help in understanding the pathophysiology of patients with HH in Brazil.