Viscerocutaneous form of loxoscelism and erythrocyte glucose-6-phosphate deficiency

Em um período de cinco anos, todos os pacientes que exibiram a forma viscerocutânea do loxoscelismo foram investigados para a deficiência de glicose-6 fosfato desidrogenase eritrocitária, e em dois pacientes em um total de sete, esta deficiência foi encontrada. Este achado sugere que esta deficiência enzimática genética poderia ser uma das causas da hemólise que ocorre em decorrência da picada por Loxosceles.In a period of time of five years, all patients who exhibited viscerocutaneous form of loxoscelism were investigated for erythrocyte glucose-6-phosphate deficiency, and in two patients out of seven it was found this deficiency. This finding suggests that this genetical enzyme deficiency could account for the hemolysis after Loxosceles bite, at least in some of the cases

Deficiência de glicose-6-fosfato desidrogenase eritrocitária em recém-nascidos do sexo masculino e sua relação com a icterícia neonatal

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the commonest red cell enzymopathy in humans, has an X-linked inheritance. The major clinical manifestations are drug induced hemolytic anemia, neonatal jaundice and chronic nonspherocytic hemolytic anemia. The incidence of neonatal hyperbilirubinemia is much greater in G6PD-deficient neonates than babies without this deficiency. The aim of this study was to ascertain the presence of neonatal jaundice in erythrocyte G6PD-deficient male newborns. Samples of umbilical cord blood from a total of 204 male newborns of the Januário Cicco School Maternity located in Natal, Rio Grande do Norte, Brazil were analyzed. The G6PD deficiency was identified by the methemoglobin reduction test (Brewer's test). The deficiency was confirmed by quantitative spectrophotometric assay for enzyme activity and cellulose acetate electrophoresis was used to identify the G6PD variant. Eight newborns were found to be G6PD deficient with four of them exhibiting jaundice during the first 48 hours after birth with bilirubin levels higher than 10 mg/dL. All deficient individuals presented the G6PD A- variant at electrophoresis. Our findings confirmed the association between G6PD deficiency and neonatal jaundice. Hence, early diagnosis of the deficiency at birth is essential to control the appearance of jaundice and to prevent the exposure of these newborns to known hemolytic agents.A deficiência de glicose-6-fosfato desidrogenase (G6PD) é a anormalidade enzimática hereditária mais frequente. É transmitida como caráter recessivo ligado ao cromossomo X e as principais manifestações clínicas são hemólise induzida por fármacos, icterícia neonatal e anemia hemolítica não esferocítica. O objetivo do estudo foi determinar a presença de icterícia neonatal em recém-nascidos do sexo masculino deficientes de glicose-6-fosfato desidrogenase. Foram analisadas 204 amostras de sangue umbilical de recém-nascidos do sexo masculino provenientes da Maternidade Escola Januário Cicco em Natal, Rio Grande do Norte. A deficiência da glicose-6-fosfato desidrogenase foi determinada através do método qualitativo da redução da metahemoglobina (teste de Brewer) e confirmada mediante determinação espectrofotométrica quantitativa da atividade da G6PD e pela eletroforese da enzima em acetato de celulose. Oito recém-nascidos apresentaram deficiência da G6PD, e quatro deles exibiram icterícia nas primeiras 48 horas depois do nascimento, com valores de bilirrubina maiores de 10 mg/dL. Todos os deficientes apresentaram a variante A-. Os dados encontrados confirmam a associação da deficiência da G6PD e a icterícia neonatal. Assim sendo, o diagnóstico precoce da deficiência logo após o nascimento é essencial ao controle do aparecimento da icterícia e para evitar o contato destes recém-nascidos com conhecidos agentes hemolíticos

A novel point mutation in a class IV glucose-6-phosphate dehydrogenase variant (G6PD São Paulo) and polymorphic G6PD variants in São Paulo State, Brazil

In this study, we used red cell glucose-6-phosphate dehydrogenase (G6PD) activity to screen for G6PD-deficient individuals in 373 unrelated asymptomatic adult men who were working with insecticides (organophosphorus and carbamate) in dengue prevention programs in 27 cities in São Paulo State, Brazil. Twenty-one unrelated male children suspected of having erythroenzymopathy who were attended at hospitals in São Paulo city were also studied. Fifteen of the 373 adults and 12 of the 21 children were G6PD deficient. G6PD gene mutations were investigated in these G6PD-deficient individuals by using PCR-RFLP, PCR-SSCP analysis and DNA sequencing. Twelve G6PD A-202A/376G and two G6PD Seattle844C, as well as a new variant identified as G6PD São Paulo, were detected among adults, and 11 G6PD A-202A/376G and one G6PD Seattle844C were found among children. The novel mutation c.660C > G caused the replacement of isoleucine by methionine (I220M) in a region near the dimer interface of the molecule. The conservative nature of this mutation (substitution of a nonpolar aliphatic amino acid for another one) could explain why there was no corresponding change in the loss of G6PD activity (64.5% of normal activity in both cases)

Search of intravascular hemolysis in patients with the cutaneous form of loxoscelism Pesquisa de hemólise intravascular na forma cutânea de loxoscelismo

Haptoglobin assay, a highly sensitive method to detect intravascular hemolysis was carried out in the sera of 19 patients referred to Hospital Vital Brazil with the cutaneous form of loxoscelism in order to investigate the occurrence of mild intravascular hemolysis. Data from this series did not show decreased levels haptoglobin, ruling out intravascular hemolysis in these patients with cutaneous form of loxoscelism.<br>Dezenove pacientes que apresentaram a forma clínica cutânea do loxoscelismo foram investigados com o propósito de pesquisar hemólise intravascular sub-clínica, lançando mão da dosagem de haptoglobina, um método altamente sensível que permite detectar discreta presença de hemólise intravascular. Não foi encontrada diminuição de haptoglobina, o que descarta uma ação hemolítica do veneno da Loxosceles nestes pacientes