Prevalência de hemoglobinas variantes em comunidades quilombolas no estado do Piauí, Brasil / Prevalence of hemoglobin variants in quilombola communities in the state of Piauí, Brazil

Resumo As hemoglobinas variantes (Hb) decorrem de mutações nos genes da globina. As variantes estruturais mais frequentes são HbS, HbC, HbD e HbE. O gene da hemoglobina S tem frequência elevada na América, enquanto que no Brasil é maior no Sudeste e Nordeste. O presente artigo tem por objetivo investigar a presença de hemoglobinas variantes em 15 comunidades quilombolas do estado do Piauí. Foram analisadas 1.239 amostras, nas quais as hemoglobinas foram triadas pela cromatografia líquida de alta eficiência (HPLC). Aplicou-se questionário referente a gênero, etnia e consanguinidade das populações. Das 1.239 amostras, 5,4% apresentaram o traço falciforme AS, as doenças falciformes SS e SC apareceram em 0,8% do total, nas hemoglobinas AC, AD e DD. Das 1.069 pessoas negras, 84 apresentaram alteração das hemoglobinas; destas, 34 eram do sexo masculino e 53 do feminino. Ocorreu a presença de 13 casamentos consanguíneos dentre as 84 alterações das hemoglobinas. O estudo das hemoglobinas variantes em 15 comunidades remanescentes de quilombos do Piauí contribui para sua educação em saúde frente aos aspectos da herança genética destas proteínas, relevante questão de saúde pública, proporcionando subsídios para a implantação do Programa Estadual da Doença Falciforme do Piauí.

Abstract Hemoglobin variants (Hb) result from mutations in globin genes, with amino acid substitution in the polypeptide chain. Among the most common structural variants are HbS, HbC, HbD and HbE. The S hemoglobin gene is a high frequency gene across America and Brazil, where it is more frequent in the Southeast and Northeast. The scope of this article is to investigate the presence of hemoglobin variants in 15 quilombos (fugitive slave communities) of Piaui. The sample was of 1,239 people and hemoglobin was screened by high-performance liquid chromatography (HPLC). A questionnaire was applied related to gender, ethnicity and consanguinity. Of the samples analyzed, 5.4% had AS sickle cell trait, while SS and SC sickle cell anemia showed a rate of 0.8%, with AC, AD and DD hemoglobin. Of the 1,069 Afro-descendants, 84 revealed hemoglobin abnormalities, 34 being male 53 being female. There were 13 consanguineous marriages among the 84 hemoglobin alterations. The study of hemoglobin variants in 15 former quilombo communities in the state of Piaui contributes to their education in health in the aspects of genetic inheritance of hemoglobin, a relevant public health issue, providing input for the implementation of the State Program of Sickle Cell Disease of Piaui.

CoagVDb: a comprehensive database for coagulation factors and their associated SAPs

The current state of the art in medical genetics is to identify and classify the functional (deleterious) or non-functional (neutral) single amino acid substitutions (SAPs), also known as non-synonymous SNPs (nsSNPs). The primary goal is to elucidate the mechanisms through which functional SAPs exert their effects, and ultimately interrogating this information for association with complex phenotypes. This work focuses on coagulation factors involved in the coagulation cascade pathway which plays a vital role in the maintenance of homeostasis in the human system. We developed an integrated coagulation variation database, CoagVDb, which makes use of the biological information from various public databases such as NCBI, OMIM, UniProt, PDB and SAPs (rsIDs/variant). CoagVDb enriched with computational prediction scores classify SAPs as either deleterious or tolerated. Also, various other properties are incorporated such as amino acid composition, secondary structure elements, solvent accessibility, ordered/disordered regions, conservation, and the presence of disulfide bonds. This specialized database provides integration of various prediction scores from different computational methods along with gene, protein, and disease information. We hope our database will act as a useful reference resource for hematologists to reveal protein structure-function relationship and disease genotype-phenotype correlation.

Detection of HIV drug resistance mutations in pregnant women receiving single dose Nevirapine in south India.

Background: Single dose of Nevirapine to prevent mother to child transmission of HIV is the commonest preventive regimen in resource-limited countries. Objectives: The objective of this study was to detect drug-resistant virus after single dose of Nevirapine (sdNVP) provided to delivering HIV seropositive (HIV+ve) women and to evaluate the time taken for its decay. Results: Of the 36 consenting HIV+ve pregnant women enrolled into the study, the mean hemoglobin and total lymphocyte counts were 10.8 g/dl and 1843 cells/mm 3 , respectively. Mean CD4 counts in 64% of women was 363 cells/mm 3 and mean viral load for 16/36 women was 28,143 copies/ml of plasma. Nevirapine-resistance mutations were detected in 28% of women at delivery; using OLA (Oligonucleotide Ligation Assay). K103N mutations were seen in 19.4% of women while the Y181C mutation was seen in 5%. Both the mutations were detected in 2.7% of women. Sequential blood samples collected at delivery, 7-10 days, 6 weeks, 4 months, 6 months and one year postpartum showed that 81% of K103N mutations and 66.7% of Y181C mutations were detected at 6 weeks postpartum . Wild-type virus had replaced the mutants by one year postpartum in all women except one. Conclusion : These observations are relevant for future treatment with antiretroviral therapy in these women for their HIV disease.

Plasmodium vivax dhfr Mutations among Isolates from Malarious Areas of Iran

The use of sulfadoxine and pyrimethamine (SP) for treatment of vivax malaria is uncommon in most malarious areas, but Plasmodium vivax isolates are exposed to SP because of mixed infections with other Plasmodium species. As P. vivax is the most prevalent species of human malaria parasites in Iran, monitoring of resistance of the parasite against the drug is necessary. In the present study, 50 blood samples of symptomatic patients were collected from 4 separated geographical regions of south-east Iran. Point mutations at residues 57, 58, 61, and 117 were detected by the PCR-RFLP method. Polymorphism at positions 58R, 117N, and 117T of P. vivax dihydrofolate reductase (Pvdhfr) gene has been found in 12%, 34%, and 2% of isolates, respectively. Mutation at residues F57 and T61 was not detected. Five distinct haplotypes of the Pvdhfr gene were demonstrated. The 2 most prevalent haplotypes were F57S58T61S117 (62%) and F57S58T61N117 (24%). Haplotypes with 3 and 4 point mutations were not found. The present study suggested that P. vivax in Iran is under the pressure of SP and the sensitivity level of the parasite to SP is diminishing and this fact must be considered in development of malaria control programs.

Polymorphic variants of β1 adrenergic receptor gene (Ser49Gly & Arg389Gly) in healthy Tamilian volunteers.

Background & objectives: Several studies reported the polymorphisms of β1-adrenergic receptor gene in healthy volunteers and its influence on cardiovascular disorders. We investigated the genotype and allele frequencies of Ser49Gly and Arg389Gly polymorphism in healthy volunteers of South Indian Tamilian population vis-à-vis other major ethnic groups. Methods: The genetic variants were determined by using Taqman 5’ nuclease assay- real time PCR analysis in 533 normal healthy volunteers (18-60 yr; M=290; F=243). The allelic discrimination analysis was done by 7700 SDS software. Results: The estimated genotype and allele frequencies of Ser49Gly and Arg389Gly polymorphism were compared with other major populations. The frequencies of the variant alleles Gly49 and Gly389 were 15.1 and 25.8 per cent respectively. Interpretation & conclusions: Our study shows that interethnic variation exists in the polymorphisms of β1-adrenergic receptor gene and the results generated in this study might serve as a genetic marker for further studies in Tamilian (South India) population.

Protein substitution to produce a processed cheese with high branched-chain amino acids of medical and genetic importance

The most important metabolic impairment in patients with advanced liver disease is characterized by low levels of circulating branched chain amino acids [BCAAs]. The etiology of such abnormal amino acid metabolism is multifactorial including protein restricted diet or inadequate nutritional intake as in protein energy malnutrition. Multiple studies report the beneficial effects of BCAAs supplementation to improve plasma amino acids imbalance, several neurologic diseases, protein energy malnutrition, and subsequently the survival rate of cirrhotic patients. In the present study we used a protein substitution technique to synthesize a new processed cheese as a dairy source rich in BCAAs, with low phenylalanine content manufactured from Ras cheese, kariesh cheese, butter oil and phenylalanine-free milk. Chemical composition, amino acids analysis, rheological properties and sensory evaluation were done to all of the cheese samples. L-Phenylalanine was selected to induce hepatic and brain affections in Begg Albino strain c [BALB/c] mice model. Effect of 2.5%, 5% and 10% protein-replacement cheese formulas was evaluated among mice groups including histopathological sections of the liver and brain; colorimetric determination for liver enzymes; serum total and differential cholesterol profile, serum albumin, globulin and total protein along with phenylalanine levels determinations. Analysis of the processed cheese sample with 10% protein substitution revealed that the protein content was 7.42 mg/g [about 50% of the content in the standard processed cheese] while fat content, acidity and moisture were nearly the same. The sensory score for all the formulas ranged from 79-88. Highest content of BCAAs along with least phenylalanine content was attained in the processed cheese with 10% protein substitution. Weight of mice fed on different substitution formulas ranged from 22.8 +/- 2.2-24.66 +/- 2.5 g compared with 17.8 +/- 1.9 g in the untreated diseased mice [P< 0.05]. Serum phenylalanine was 1.822 +/- 0.42 mg/dl in the mice fed on 10% protein substitution formula compared to 6.2 +/- 1.32 mg/dl in the untreated mice [P < 0.01]. There was a highly significant difference [P <0.01] between untreated mice and mice fed on 10% substitution cheese formula as regards the serum protein, Aspartate Transaminase [AST] and Alanine Transaminase [ALT]. The improvement in histopathological findings was more apparent in the mice fed on 10% formula cheese. The manufactured processed cheese with 10% protein substitution was proved to have a more nutritional therapeutic potential that can help in the implementation of dietary management in many medical and genetic disorders with liver and brain affections

Structure-function analysis of two variants of mumps virus hemagglutinin-neuraminidase protein

A point mutation from guanine (G) to adenine (A) at nucleotide position 1081 in the hemagglutinin-neuraminidase (HN) gene has been associated with neurovirulence of Urabe AM9 mumps virus vaccine. This mutation corresponds to a glutamic acid (E) to lysine (K) change at position 335 in the HN glycoprotein. We have experimentally demonstrated that two variants of Urabe AM9 strain (HN-A1081 and HN-G1081) differ in neurotropism, sialic acidbinding affinity and neuraminidase activity. In the present study, we performed a structure-function analysis of that amino acid substitution; the structures of HN protein of both Urabe AM9 strain variants were predicted. Based on our analysis, the E/K mutation changes the protein surface properties and to a lesser extent their conformations, which in turn reflects in activity changes. Our modeling results suggest that this E/K interchange does not affect the structure of the sialic acid binding motif; however, the electrostatic surface differs drastically due to an exposed short alpha helix. Consequently, this mutation may affect the accessibility of HN to substrates and membrane receptors of the host cells. Our findings appear to explain the observed differences in neurotropism of these vaccine strains.

SHV-28, an extended-spectrum beta-lactamase produced by a clinical isolate of Klebsiella pneumoniae in south India.

SHV-28, an extended spectrum beta-lactamase from a clinical isolate of Klebsiella pneumoniae , had an isoelectric point of 7.6 and a substrate profile showing preferential hydrolysis for cefotaxime over ceftazidime. It differed from SHV-1 by one amino acid substitution. The conserved S-T-F-K and K-T-G motifs were identified by SHV-28 protein sequencing.

Hemoglobin E disorders in Eastern Uttar Pradesh.

The distribution of hemoglobin E (alpha2beta2 26Glu (R)Lys ) is mostly restricted to Northeastern India. While evaluating the patients of jaundice, we came across two cases of hemoglobin E (Hb E) disorders. The first case is in a 22-year-old Bengali male and the second case of Hb E/beta thalassemia in a 5-year-old Hindu boy. The family study revealed Hb E trait in both the parents of Case 1, whereas in Case 2, the father was found to have Hb E trait and the mother had beta -thalassemia minor, thus confirming the diagnosis. Herein, we present the laboratory diagnosis and comparative data of the spectrum of Hb E disorders (i.e., heterozygous Hb E trait, homozygous Hb E disease and compound heterozygous Hb E/beta -thalassemia) that was found in our index cases and their parents.

Genetic divergence between two sympatric species of the Lutzomyia longipalpis complex in the paralytic gene, a locus associated with insecticide resistance and lovesong production

The sandfly Lutzomyia longipalpis s.l. is the main vector of American Visceral Leishmaniasis. L. longipalpis s.l. is a species complex but until recently the existence of cryptic sibling species among Brazilian populations was a controversial issue. A fragment of paralytic (para), a voltage dependent sodium channel gene associated with insecticide resistance and courtship song production in Drosophila, was isolated and used as a molecular marker to study the divergence between two sympatric siblings of the L. longipalpis complex from Sobral, Brazil. The results revealed para as the first single locus DNA marker presenting fixed differences between the two species in this locality. In addition, two low frequency amino-acid changes in an otherwise very conserved region of the channel were observed, raising the possibility that it might be associated with incipient resistance in this vector. To the best of our knowledge, the present study represents the first population genetics analysis of insecticide resistance genes in this important leishmaniasis vector.

Genotypic resistance profile of HIV-1 protease gene: a preliminary report from Vellore, south India.

HIV-1 subtypes other than B are responsible for most new HIV infections worldwide; virus sequence data for drug resistance is described only from a limited number of non-B subtype HIV-1. This study is on mutations and polymorphisms of HIV-1 protease gene that can predict drug resistance in subtype C. The genotypic resistance assay was carried out on 38 HIV-1 strains with their plasma RNA and in nine, the proviral protease gene was sequenced. The treatment naïve strains showed minor resistance mutations, there were no major resistance mutations in the protease gene. We suggest the use of resistance testing to monitor individuals on therapy and also before initiation of therapy, gathering more sequence information for a data bank of Indian strains.

Molecular characterization of genes encoding the quinolone resistance determining regions of Malaysian Streptococcus pneumoniae strains.

Genes encoding the quinolones resistance determining regions (QRDRs) in Streptococcus pneumoniae were detected by PCR and the sequence analysis was carried out to identify point mutations within these regions. The study was carried out to observe mutation patterns among S. pneumoniae strains in Malaysia. Antimicrobial susceptibility testing of 100 isolates was determined against various antibiotics, out of which 56 strains were categorised to have reduced susceptibility to ciprofloxacin (>or=2 microg/mL). These strains were subjected to PCR amplification for presence of the gyrA, parC , gyrB and parE genes. Eight representative strains with various susceptibilities to fluoroquinolones were sequenced. Two out of the eight isolates that were sequenced were shown to have a point mutation in the gyrA gene at position Ser81. The detection of mutation at codon Ser81 of the gyrA gene suggested the potential of developing fluoroquinolone resistance among S. pneumoniae isolates in Malaysia. However, further experimental work is required to confirm the involvement of this mutation in the development of fluoroquinolone resistance in Malaysia.

Detection of mutation in isoniazid-resistant Mycobacterium tuberculosis isolates from tuberculosis patients in Belarus.

The aim of this study was to investigate the frequency, location and type of katG mutations in Mycobacterium tuberculosis strains isolated from patients in Belarus. Forty two isoniazid-resistant isolates were identified from sputum of 163 patients with active pulmonary tuberculosis. Drug susceptibility testing was determined by using CDC standard conventional proportional method and BACTEC system. Standard PCR method for detection of isoniazid resistance associated mutations was performed by katG gene amplification and DNA sequencing. Most mutations were found in katG gene codons 315, 316 and 309. Four types of mutations were identified in codon 315: AGC-->ACC (n=36) 85%, AGC-->AGG (n=1) 2.3%, AGC-->AAC (n=2) 4.7%, AGC-->GGC (n=1) 2.3%. One type of mutation was found in codon 316: GGC-->AGC (n=18) 41.4%, four types of mutations were detected in codon 309: GGT-->GGT (n=7) 16.1%, GGT-->GCT (n=4) 9.2%, GGT-->GTC (n=3)6.9%, GGT-->GGG (n=1) 2.7%. The highest frequency of mutations sharing between primary and secondary infections was found in codon 315.

Permanent neonatal diabetes due to KCNJ11 gene mutation.

Permanent neonatal diabetes mellitus (PNDM) is characterized by the onset of diabetes within the first six months of life and insulin dependence life long. It has been recently discovered that mutation in KCNJ11 gene encoding Kir6.2, the pore forming subunit of ATP sensitive potassium channel (K ATP) is the most common cause and such patients may respond better to oral sulphonylurea drugs than insulin. Here is a rare case of permanent neonatal diabetes due to R20IC mutation in KCNJ11 gene.

Mechanism of DNA-binding loss upon single-point mutation in p53.

Over 50% of all human cancers involve p53 mutations,which occur mostly in the sequence-specific DNA-binding central domain (p53c), yielding little/non-detectable af?nity to the DNA consensus site.Despite our current understanding of protein-DNA recognition,the mechanism(s) underlying the loss in protein-DNA binding afnity/ specificity upon single-point mutation are not well understood. Our goal is to identify the common factors governing the DNA-binding loss of p53c upon substitution of Arg 273 to His or Cys,which are abundant in human tumours. By computing the free energies of wild-type and mutant p53c binding to DNA and decomposing them into contributions from individual residues, the DNA-binding loss upon charge/noncharge -conserving mutation of Arg 273 was attributed not only to the loss of DNA phosphate contacts, but also to longer-range structural changes caused by the loss of the Asp 281 salt-bridge. The results herein and in previous works suggest that Asp 281 plays a critical role in the sequence-specific DNA-binding function of p53c by (i)orienting Arg 273 and Arg 280 in an optimal position to interact with the phosphate and base groups of the consensus DNA, respectively, and (ii) helping to maintain the proper DNA-binding protein conformation.

HFE mutation H63D predicts risk of iron over load in thalassemia intermedia irrespective of blood transfusions.

Iron overload is a well-documented complication in thalassemia intermedia. Moreover, it is seen that the number of blood transfusions received does not correlate with the degree of overload. Since, HFE gene is associated with iron overload; the present study was conducted in an attempt to evaluate its role in thalassemia intermedia. The subjects were consecutive thalassemia intermedia cases attending the Hematology outpatient clinic. Controls were healthy hospital staff with negative family history of hemolytic anemia or liver disease. The molecular analysis for HFE mutations H63D and C282Y were done with primers described earlier. ELISA was used to measure serum ferritin. Sixty-three patients of thalassemia intermedia including 48 beta-homozygous/heterozygous thalassemia intermedia and 15 HbE-beta-thalassemia were studied. Six (12.5%) of the former and two (13.3%) of the latter were heterozygous for H63D; one of which, a 51-year old male also had clinical features of hemochromatosis. In healthy controls, prevalence of H63D heterozygosity was 7.5% (6/80). An interesting feature observed was that though the age and transfusions taken were similar in both groups, the serum ferritin greater than 500 ng/dl were observed in all patients (100%) with HFE mutation whereas it was seen in 12/42 (28.6 %) of patients without the mutation (p = 0.002). Thus, it is concluded that thalassemia intermedia patients with co-existent HFE mutation have a higher likelihood of developing iron overload and may require early iron chelation.

LEPR p. Q223R, Beta 3-AR p. W64R and LEPc. -2548G>A gene variants in obese Brazilian subjects

Obesity is due to the combined effects of genes, environment, lifestyle, and the interactions of these factors. The adrenergic receptor ¦Â3 (¦Â3-AR), leptin (LEP) and leptin receptor (LEPR) genes have been intensively evaluated in the search of variants that could be related to obesity and its cardiometabolic complications. The results of most of these studies have been controversial. In the present study, we investigated the relationship of the ¦Â3-AR p.W64R, LEP c.-2548G>A and LEPR p.Q223R gene variants with body mass index (BMI), in Brazilian subjects of different genetic backgrounds and ethnic origins. Two hundred obese patients (60 males, 140 females, BMI ¡Ý 30 kg/m2) were screened and compared to 150 lean healthy subjects (63 males, 87 females, BMI ¡Ü 24 kg/m2). Genomic DNA was extracted and amplified by polymerase chain reaction. Polymerase chain reaction products were digested with specific restriction enzymes and separated by electrophoresis. There was no significant difference in the genotype frequency of the ¦Â3-AR p.W64R and the LEP c.-2548G>A polymorphisms, between lean and obese subjects. However, the genotype and allele frequencies of the LEPR p.Q223R variant were significantly different between the normal weight and obese groups. Haplotype analysis has shown an association between the G/G allelic combination of c.-2548G>A LEP and c.668A>G LEPR, in obese subjects. Our results suggest that genetic variability in the leptin receptor is associated with body weight regulation, the LEPR p.Q223R variant being related to BMI increase. The haplotype combination of LEP c.-2548G>A and LEPR p.Q223R variants was related to a 58% increase in obesity risk.

Disease severity associated with cystic fibrosis mutations deltaF508 and S549R[T-G]

We compared the clinical severity associated with the two cystic fibrosis [CF] mutations S549R[T[R]G] and deltaF508. Clinical and biochemical variables of CF were compared in two age- and sex-matched groups of CF children in the United Arab Emirates [UAE]. The clinical severity of mutations S549R[T[R]G] and delta F508 showed comparable patterns, with very low Shwachman scores and high sweat chloride levels. We conclude that patients homozygous for the CF mutations deltaF508 and S549R[T[R]G] have a severe clinical presentation and illness and are indistinguishable on clinical grounds