Prevalence of the most common pathogenic variants in three genes for inborn errors of metabolism associated with sudden unexpected death in infancy: a population-based study in south Brazil.

Citrullinemia type 1 (CTLNI), long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD), and mut0 methylmalonic acidemia (mut0 MMA) are inborn errors of metabolism (IEMs) associated with sudden unexpected death in infancy (SUDI). Its most common pathogenic variants are: c.1168G>A (CTLNI, ASS1 gene), c.1528G>C (LCHADD, HADHA gene), c.655A>T and c.1106G>A (mut0 MMA, MUT gene). Considering the absence of estimates regarding the incidence of these diseases in Brazil, this study sought to investigate the prevalence of its main pathogenic variants in a healthy population in the southern region of the country. A total of 1,000 healthy subjects from Rio Grande do Sul were included. Genotyping was performed by real-time PCR. Individuals found to be heterozygous for c.1528G>C underwent further acylcarnitine profile analysis by tandem mass spectrophotometry. Allele and genotype frequencies were calculated considering Hardy-Weinberg equilibrium. The c.1528G>C variant was detected in heterozygosity in two subjects (carrier frequency = 1:500; allele frequency = 0.001; minimum prevalence of LCHADD = 1: 1,000,000), whose acylcarnitine profiles were normal. Variants c.1168G>A, c.655A>T, and c.1106G>A were not identified. These results denote the rarity of these IEMs in Southern Brazil, highlighting the need to expand the investigation of IEMs in relation to infant morbidity and mortality within the country.

Oxidative and nitrative stress and pro-inflammatory cytokines in Mucopolysaccharidosis type II patients: effect of long-term enzyme replacement therapy and relation with glycosaminoglycan accumulation.

Mucopolysaccharidosis type II (MPS II) is a lysosomal storage disease caused by a deficient activity of iduronate-2-sulfatase, leading to abnormal accumulation of glycosaminoglycans (GAG). The main treatment for MPS II is enzyme replacement therapy (ERT). Previous studies described potential benefits of six months of ERT against oxidative stress in patients. Thus, the aim of this study was to investigate oxidative, nitrative and inflammatory biomarkers in MPS II patients submitted to long term ERT. It were analyzed urine and blood samples from patients on ERT (mean time: 5.2years) and healthy controls. Patients presented increased levels of lipid peroxidation, assessed by urinary 15-F2t-isoprostane and plasmatic thiobarbituric acid-reactive substances. Concerning to protein damage, urinary di-tyrosine (di-Tyr) was increased in patients; however, sulfhydryl and carbonyl groups in plasma were not altered. It were also verified increased levels of urinary nitrate+nitrite and plasmatic nitric oxide (NO) in MPS II patients. Pro-inflammatory cytokines IL-1ß and TNF-α were increased in treated patients. GAG levels were correlated to di-Tyr and nitrate+nitrite. Furthermore, IL-1ß was positively correlated with TNF-α and NO. Contrastingly, we did not observed alterations in erythrocyte superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase activities, in reduced glutathione content and in the plasmatic antioxidant capacity. Although some parameters were still altered in MPS II patients, these results may suggest a protective role of long-term ERT against oxidative stress, especially upon oxidative damage to protein and enzymatic and non-enzymatic defenses. Moreover, the redox imbalance observed in treated patients seems to be GAG- and pro-inflammatory cytokine-related.