Enzyme replacement therapy interruption in patients with Mucopolysaccharidoses: Recommendations for distinct scenarios in Latin America.

BACKGROUND: Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders, leading to the progressive accumulation of glycosaminoglycans (GAGs) and the subsequent compromising of tissues and organ malfunction. Although incurable, most types of MPS can be treated with enzyme replacement therapy (ERT), an approach that has had positive effects on the natural clinical evolution and which impact has been extensively investigated. Unfortunately, to date, there is relatively little data regarding the effects of ERT interruption, especially in Latin America, where such interruption may be frequent due to a variety of issues (for instance, difficulties involving logistics, reimbursement and/or payment withdrawal). METHOD: A group of medical professionals from Latin America with experience in Genetics, Pediatrics and Neurology held an Advisory Board Meeting in the city of São Paulo, in October 2018, to discuss the issue of ERT interruptions in the region and recommendations health care professionals on how to deal with these interruptions and better assess the therapeutic effects of ERT. CONCLUSION: Recommendations provided by the experts may support physicians in dealing with the most common reasons for ERT interruptions in Latin America. Most importantly, recommendations for data collection at specific timepoints (at baseline, throughout the treatment and during the interruption period of ERT and after its resumption) can significantly improve the collection of real world evidence on the effects of ERT and its interruptions, supporting health care professionals and policy makers in the decision making regarding the provision of these therapies for MPS patients.

Evaluation of plasma biomarkers of inflammation in patients with maple syrup urine disease.

Maple syrup urine disease (MSUD) is an autosomal recessive inherited disorder that affects branched-chain amino acid (BCAA) catabolism and is associated with acute and chronic brain dysfunction. Recent studies have shown that inflammation may be involved in the neuropathology of MSUD. However, these studies have mainly focused on single or small subsets of proteins or molecules. Here we performed a case-control study, including 12 treated-MSUD patients, in order to investigate the plasmatic biomarkers of inflammation, to help to establish a possible relationship between these biomarkers and the disease. Our results showed that MSUD patients in treatment with restricted protein diets have high levels of pro-inflammatory cytokines [IFN-γ, TNF-α, IL-1ß and IL-6] and cell adhesion molecules [sICAM-1 and sVCAM-1] compared to the control group. However, no significant alterations were found in the levels of IL-2, IL-4, IL-5, IL-7, IL-8, and IL-10 between healthy controls and MSUD patients. Moreover, we found a positive correlation between number of metabolic crisis and IL-1ß levels and sICAM-1 in MSUD patients. In conclusion, our findings in plasma of patients with MSUD suggest that inflammation may play an important role in the pathogenesis of MSUD, although this process is not directly associated with BCAA blood levels. Overall, data reported here are consistent with the working hypothesis that inflammation may be involved in the pathophysiological mechanism underlying the brain damage observed in MSUD patients.

Major Contribution of Genomic Copy Number Variation in Syndromic Congenital Heart Disease: The Use of MLPA as the First Genetic Test.

Congenital heart disease (CHD) is the most common congenital disorder among live births. When associated with extracardiac abnormalities, it is characterized as a syndromic heart disease (syndromic CHD) and corresponds to 25% of all liveborn infants with a heart defect. The etiology in about 65% of the cases still remains unknown, and in about 35% of the patients, it is associated with genetic factors. In the present study, MLPA and SNP-array techniques were used to investigate a group of 47 patients with syndromic CHD. In total, 16 defects (34%) were identified, of which 12 (25.5%) were classified as pathogenic or probably pathogenic. The most frequent abnormalities were 22q11.2 deletion (22q11.2 deletion syndrome) and 7q11.23 deletion (Williams-Beuren syndrome). We also show that rarer malformations may be associated with syndromic CHD, such as 14q32.33 deletion as well as 17q25.3, 15q11.2 (BP1-BP2), 22q13.31, and 12p13.31 (SLC2A3) duplications. The present study demonstrates that CNVs are important causal factors and should be studied in patients with syndromic CHD. Furthermore, the use of MLPA as a first screening test was appropriate, as this less expensive technology detected 11 of the 12 pathogenic abnormalities (91.6%).

Correction: Biotinidase deficiency: Genotype-biochemical phenotype association in Brazilian patients.

[This corrects the article DOI: 10.1371/journal.pone.0177503.].

The phenotypic spectrum of congenital Zika syndrome.

In October 2015, Zika virus (ZIKV) outbreak the Brazilian Ministry of Health (MoH). In response, the Brazilian Society of Medical Genetics established a task force (SBGM-ZETF) to study the phenotype of infants born with microcephaly due to ZIKV congenital infection and delineate the phenotypic spectrum of this newly recognized teratogen. This study was based on the clinical evaluation and neuroimaging of 83 infants born during the period from July, 2015 to March, 2016 and registered by the SBGM-ZETF. All 83 infants had significant findings on neuroimaging consistent with ZIKV congenital infection and 12 had confirmed ZIKV IgM in CSF. A recognizable phenotype of microcephaly, anomalies of the shape of skull and redundancy of the scalp consistent with the Fetal Brain Disruption Sequence (FBDS) was present in 70% of infants, but was most often subtle. In addition, features consistent with fetal immobility, ranging from dimples (30.1%), distal hand/finger contractures (20.5%), and feet malpositions (15.7%), to generalized arthrogryposis (9.6%), were present in these infants. Some cases had milder microcephaly or even a normal head circumference (HC), and other less distinctive findings. The detailed observation of the dysmorphic and neurologic features in these infants provides insight into the mechanisms and timings of the brain disruption and the sequence of developmental anomalies that may occur after prenatal infection by the ZIKV.

Identifying CNVs in 15q11q13 and 16p11.2 of Patients with Seizures Increases the Rates of Detecting Pathogenic Changes.

Chromosomal changes are frequently observed in patients with syndromic seizures. Understanding the genetic etiology of this pathology is crucial for the guidance and genetic counseling of families as well as for the establishment of appropriate treatment. A combination of MLPA kits was used to identify pathogenic CNVs in a group of 70 syndromic patients with seizures. Initially, a screening was performed for subtelomeric changes (MLPA P036 and P070 kits) and for the regions most frequently related to microdeletion/microduplication syndromes (MLPA P064). Subsequently, the MLPA P343 was used to identify alterations in the 15q11q13, 16p11.2, and 22q13 regions. Screening with MLPA P343 allowed a 10-15.7% increase in the detection rate of CNVs reinforcing the importance of investigating changes in 15q11q13 and 16p11.2 in syndromic patients with seizures. We also demonstrated that the MLPA technique is an alternative with a great diagnostic potential, and we proposed its use as part of the initial assessment of syndromic patients with seizures.

Biotinidase deficiency: clinical and genetic studies of 38 Brazilian patients.

BACKGROUND: Biotinidase deficiency (BD) is an inborn error of metabolism in which some genetic variants correlate with the level of enzyme activity. Biotinidase activity, however, may be artifactually low due to enzyme lability, premature birth, and jaundice; this hinders both phenotypic classification and the decision to implement therapy. This study sought to characterize the clinical and genetic profile of a sample of Brazilian patients exhibiting reduced biotinidase activity. METHODS: This observational, multicenter study used a convenience sampling strategy, with sequencing of exons 2, 3, and 4 of the BTD gene. RESULTS: The sample comprised 38 individuals with biochemical phenotypes defined a priori on the basis of biotinidase activity in serum/plasma (2 with profound deficiency, 9 with partial deficiency, 15 heterozygous, 1 borderline between partial deficiency and heterozygosity, 2 borderline between heterozygous and normal) or dried blood spot sample (n = 9, all with unspecified deficiency). Most patients were from Southern Brazil (n = 29/38) and were identified by neonatal screening (n = 33/38). Parental consanguinity was reported in two cases. The most commonly found genetic variants were c.1330G > C (p.D444H), c.755A > G (p.D252G), and c.[511G > A;1330G > C] (p.[A171T;D444H]), with allele frequencies of 50%, 9.4%, and 5.4% respectively. Three novel pathogenic variants were identified (c.119 T > C or p.L40P, c.479G > A or p.C160Y, and c.664G > A or p.D222N). Twenty-nine patients had two pathogenic variants detected (with cis/trans status ascertained in 26/29), six had only one variant, and three had no pathogenic variants detected. Genotyping confirmed the original phenotypic classification based on enzyme activity in 16/26 cases. Three polymorphic variants were identified in control individuals, of which two were nonpathogenic (c.1171C > T or p.P391S and c.1413 T > C or p.C471C, with a frequency of 1.5% and 5.5% respectively) and one pathogenic (c.1330G > C, frequency 4%). CONCLUSIONS: Our findings suggest that partial BD is the most common form of BD in Brazil, and expand current knowledge on the allelic heterogeneity of this condition.