Taciane Alegra

Enzyme replacement therapy for Fabry disease: a systematic review and meta-analysis

The specific treatment available for Fabry disease (FD) is enzyme replacement therapy (ERT) with agalsidase alfa or beta. A systematic review and meta-analysis was conducted to assess the efficacy and safety of ERT for FD. Only double-blind, randomized clinical trials (RCTs) comparing agalsidase alfa or beta and placebo were included. ERT with either agalsidase alfa or beta was considered similar for the purposes of analysis. Ten RCTs were identified, which showed improvements in neuropathic pain, in heart abnormalities and in globotriaosylceramide (GL-3) levels. A meta-analysis showed increased odds for fever, rigors, development of IgG antibodies to agalsidase, and no significant association with development of hypertension or reduction in the QRS complex duration on electrocardiogram. The RCTs included in this comparison enrolled few patients, were highly heterogeneous, and were focused mainly on surrogate endpoints, limiting any conclusions as to the real effect of ERT for FD. The available evidence suggests that response to ERT is variable across patient subgroups and that agalsidase may slow progression of FD, with slight improvement of existing changes. Nevertheless, many uncertainties remain, and further studies are necessary.

Mucolipidosis II and III alpha/beta in Brazil: analysis of the GNPTAB gene.

UNLABELLED Mucolipidosis II and III (MLII and MLIII) alpha/beta are rare autosomal recessive lysosomal storage diseases (LSDs) caused by pathogenic variations in the GNPTAB gene. GNPTAB gene codes for the α and β subunits of phosphotransferase, the enzyme responsible for synthesis of the mannose-6-phosphate (M6P) marker that directs lysosomal enzymes to the lysosome. OBJECTIVES The objective of this study is to identify sequence variations of the GNPTAB gene in Brazilian patients with MLII and MLIII alpha/beta. METHOD Sequencing of the GNPTAB gene was performed in samples of gDNA extracted from the peripheral blood of patients with MLII/III diagnosed at a national reference center for LSDs. RESULTS Twelve unrelated patients, from several regions of Brazil, were included in this study. Only one was born of consanguineous parents. All patients were found to carry at least one nonpathogenic variation. Nine causal sequence variations were found: c.242G>T (p.W81L); c.1123C>T (p.R375X); c.1196C>T (p.S399F); c.1208T>C (p.I403T); c.1514G>A (p.C505Y); c.1759C>T (p.R587X); c.2808A>G (p.Y937_M972del, novel mutation); c. 2269_2273delGAAAC (p.E757KfsX2, novel mutation); and c.3503_3504delTC (p.L1168QfsX5). Both pathogenic variations were identified in 8 of 12 patients; in four patients, only one pathogenic variation was identified. Mutation c.3503_3504delTC, located in exon 19, was the most frequent pathogenic variation found (n=11/24 alleles). The deleterious effect of the c.2808A>C mutation on splicing was confirmed by cDNA analysis. DISCUSSION/CONCLUSIONS Our findings confirm that the GNPTAB gene presents broad allelic heterogeneity and suggests that, in Brazilian ML II and III patients, screening for mutations should begin at exon 19 of the GNPTAB gene. Further analyses will be conducted on patients in whom both pathogenic mutations have not been found in this study.

Quality of Life of Brazilian Patients with Gaucher Disease and Fabry Disease

OBJECTIVE To evaluate QoL in a sample of Brazilian patients with Gaucher (GD) and Fabry (FD) disease using the SF-36 survey. METHOD Observational cross-sectional study. The SF-36 survey was administered to cognitively able patients 12 years or older, who were seen in the Medical Genetics Service of Hospital de Clínicas de Porto Alegre, Brazil. RESULTS Thirty-five patients were included in the study (GD = 21, FD = 14), mean age was 29.8 ± 14.2 years and 29 (82.9%) were receiving ERT. Patients with GD receiving ERT had better scores in the general health (p = 0.046) domain of the SF-36 than patients with FD receiving ERT. Comparison of patients with GD naive to ERT and those receiving ERT revealed differences only in the bodily pain domain (p = 0.036). The Zimran score showed a moderate negative correlation with the following domains of the SF-36: physical functioning (p = 0.035), role-physical (p = 0.036), general health (p = 0.023) and role emotional (p = 0.021). DISCUSSION AND CONCLUSION Although limited because of the small number of patients included, findings suggest that patients with GD receiving ERT have a better QoL than patients with FD or with GD not receiving ERT. Imiglucerase has a beneficial effect against pain for patients with GD. Further studies should be conducted to confirm our findings.

A de novo or germline mutation in a family with Mucolipidosis III gamma: Implications for molecular diagnosis and genetic counseling

Mucolipidosis III (ML III) gamma is a very rare autosomal-recessive disorder characterized by the abnormal trafficking and subcellular localization of lysosomal enzymes due to mutations in the GNPTG gene. The present study consists of a report of a Brazilian compound heterozygote patient with ML III gamma resulting from one mutant paternal allele and one allele that had most likely undergone a de novo or maternal germline mutation. This is the first report of a de novo mutation in ML III gamma. This finding has significant implications for genetic counseling.

The Management of Gaucher Disease in Developing Countries: A Successful Experience in Southern Brazil

Objective: Gaucher disease (GD) is a genetic disease caused by glucocerebrosidase deficiency. GD is treated by enzyme replacement therapy (ERT) with imiglucerase, a high-cost drug provided by the Brazilian Ministry of Health (BMH). This study reports the implementation of the BMH guidelines for GD in the southernmost state of the country. Methods: We review the clinical and laboratorial data for patients seen at the reference center for GD from Rio Grande do Sul, Brazil (July 2003 to June 2006). Results: Twenty-five patients were included in this study. At baseline, 19/20 were on ERT (mean dosage of imiglucerase = 51.8 U/kg/infusion), 3/17 presented anemia, and 5/16 thrombocytopenia. The amount of imiglucerase prescribed to these patients was adjusted according to the guidelines in July 2003; out of them, 18 were receiving ERT in the reference center at month 36 (mean dosage of imiglucerase = 27.5 U/kg/infusion), 2/18 presented anemia, and 4/18 presented thrombocytopenia. The analysis of the liver, spleen, and bone data presented some limitations, but the available information suggests that patients did not deteriorate. GD patients who initiated ERT after July 2003 (n = 5) received lower dosage of imiglucerase since the beginning of the treatment; most of them demonstrated clinical and laboratorial response. From baseline to month 36, the consumption of imiglucerase by the reference center showed a significant reduction, which represented savings of USD 3 million to the public health system. Conclusions: The model of care of GD patients suggested by the BMH guidelines appears to be cost-effective and could be an example for management of rare diseases in underdeveloped countries.

Efficacy and safety of intravenous laronidase for mucopolysaccharidosis type I: A systematic review and meta-analysis

Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disease caused by deficient activity of alpha-L-iduronidase. Intravenous (IV) enzyme replacement therapy (ERT) with laronidase is currently used for treating patients with MPS I. Objective To evaluate the efficacy and safety of IV laronidase for MPS I. Methods A systematic literature review was performed by searching the ClinicalTrials.gov, MEDLINE/PubMed, EMBASE, LILACS, and Cochrane Library databases, limited to clinical trials published until December 31, 2016. The first inclusion criterion was being a randomized controlled trial (RCT). If < five RCTs were identified, open-label and nonrandomized trials, controlled or uncontrolled (quasi-experimental), including ≥ five patients, and evaluating relevant outcomes defined a priori, would also be included. For meta-analysis, primary inferences were based on random-effects models. Assessment of article quality was performed in accordance with the GRADE criteria. The Cochrane Risk of Bias tool was used to examine the risk of bias for RCTs. Results The selection phase retrieved 632 articles. During the first phase of selection, 158 had the abstract or full text read for assessment of eligibility, of which nine (two RCTs) were included for qualitative synthesis. Four papers were included in the meta-analysis, which was performed for the following outcomes: occurrence of treatment-emergent or infusion-related adverse events (65%; 95%CI 53, 76), mild in most cases; development of IgG antibodies to laronidase (88%; 95%CI 67, 100); apnea-hypopnea index (not significant—NS), urinary glycosaminoglycans (GAGs) [mean change -65.5 μg/mg creatinine (95%CI -68.8, -62.3)], liver size [mean change -31.03% (95%CI -36.1, -25.9)], left ventricular mass index (LVMI) [mean change -1.8 (95%CI -2.32, -0.25)], and distance covered in the 6-minute walk test (NS). Among the outcomes not included in meta-analysis, we found evidence for benefit of laronidase only on shoulder flexion. Conclusions Our findings suggest that IV laronidase effectively reduces urinary GAGs excretion, hepatomegaly and LVMI, and can improve shoulder flexion in MPS I patients. Laronidase appears to be safe in the studied population.

Enigmatic in vivo GlcNAc-1-phosphotransferase (GNPTG) transcript correction to wild type in two mucolipidosis III gamma siblings homozygous for nonsense mutations.

Mucolipidosis (ML) III gamma is a rare autosomal-recessive disorder caused by pathogenic mutations in the GNPTG gene. GNPTG encodes the γ-subunit of GlcNAc-1-phosphotransferase that catalyzes mannose 6-phosphate targeting signal synthesis on soluble lysosomal enzymes. ML III gamma patients are characterized by missorting of lysosomal enzymes. In this report, we describe the probable occurrence of mRNA editing in two ML III gamma patients. Patients A and B (siblings) presented at the adult age with a typical clinical picture of ML III gamma, mainly compromising bone and joints, and high levels of lysosomal enzymes in plasma and low levels in fibroblasts. Both were found to be homozygous for c.-112C>G and c.328G>T (p.Glu110Ter) mutations in genomic DNA (gDNA) analysis of GNPTG. Analysis of complementary DNA (cDNA), however, showed normal genotypes for both patients. Low GNPTG mRNA expression was observed in both patients. The mRNA editing can explain the differences found in patients A and B regarding gDNA and cDNA analysis, and the mild clinical phenotype associated with homozygosity for a nonsense mutation. Our results suggest that mRNA editing can be more frequent than expected in monogenic disorders and that GNPTG analysis should be performed on gDNA.

Pitfalls in the prenatal diagnosis of mucolipidosis II alpha/beta: A case report

Mucolipidosis II alpha/beta is an autosomal recessive disorder caused by deficient activity of GlcNAc-1-phosphotransferase. We report the prenatal diagnosis of a fetus who was found to exhibit normal levels of lysosomal enzymes in the amniotic fluid but low levels in amniocytes, and who was found to be heterozygous for the most common GNPTAB mutation. As in some carriers of Mucolipidosis II biochemical abnormalities may hinder prenatal diagnosis, we suggest DNA analysis should be performed whenever possible.

Exome sequencing for mucolipidosis III: Detection of a novel GNPTAB gene mutation in a patient with a very mild phenotype

Mucolipidosis II and III alpha/beta (ML II/III alpha/beta) are rare autosomal recessive lysosomal storage diseases that are caused by a deficiency of UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase, the enzyme responsible for the synthesis of the mannose 6-phosphate targeting signal on lysosomal hydrolases. A Brazilian patient suspected of having a very mild ML III was investigated using whole next-generation sequencing (NGS). Two mutations in the GNPTAB gene were detected and confirmed to be in trans status by parental analysis: c.1208T>C (p.Ile403Thr), previously reported as being pathogenic, and the novel mutation c.1723G>A (p.Gly575Arg). This study demonstrates the effectiveness of using whole NGS for the molecular diagnosis of very mild ML III alpha/beta patients.

Efficacy and safety of idursulfase therapy in patients with mucopolysaccharidosis type II with and without comparison to placebo: systematic review and meta-analysis

Mucopolysaccharidosis type II (MPS II) is a genetic disease of broad clinical spectrum, characterized by a deficiency of the enzyme iduronate2-sulfatase. The aim of this study was to assess whether enzyme replacement therapy (ERT) with idursulfase (IDS) for MPS II is effective and safe. PubMed/MEDLINE, Embase, LILACS, and Cochrane Library were searched until November 30, 2012. Only five articles met the inclusion criteria (randomized controlled trials - RCTs, or open-label trials/prospective case series including > 5 patients and evaluating relevant outcomes). A meta-analysis was performed for forced vital capacity (FVC; absolute and %) and for distance walked on the 6-minute walking test (6MWT). There was a statistically significant increase, but not clinically relevant, in both variables; an increased risk for development of mild infusion-related reactions and IgG antibodies to IDS were also found. The data suggest that ERT with IDS is safe and has a potential benefit for MPS II patients, but further studies are required.A mucopolissacaridose tipo II (MPS II) e uma doenca genetica de amplo espectro clinico, caracterizada por deficiencia da enzima iduronato-2sulfatase. Revisao sistematica avaliou a eficacia e seguranca da terapia de reposicao enzimatica (TRE) com idursulfase (IDS) na MPS II. As bases de dados PubMed/MEDLINE, Embase, LILACS e Biblioteca Cochrane foram pesquisados ate 30 de novembro de 2012. Apenas cinco estudos preencheram os criterios de inclusao (ensaios clinicos randomizados - ECRs, ECRs abertos ou series de caso prospectivas, incluindo cinco ou mais pacientes e avaliando desfechos relevantes). Metanalise foi realizada para capacidade vital forcada (CVF; valores absolutos e em %) e para a distância percorrida no teste da caminhada dos seis minutos, com mudancas significativas em ambas as variaveis; tambem foi encontrado risco aumentado de reacoes leves relacionadas a infusao e de desenvolvimento de anticorpos IgG a IDS. Em face dos dados apresentados neste estudo, conclui-se que a TRE com IDS e segura e tem beneficio potencial em MPS II, mas estudos adicionais sao necessarios.