Abstract Spinal muscular atrophy (SMA) is considered one of the most common autosomal recessive disorders, with an estimated incidence of 1 in 10,000 live births. Testing for SMA has been recommended for inclusion in neonatal screening (NBS) panels since there are several therapies available and there is evidence of greater efficacy when introduced in the pre/early symptomatic phases. In Brazil, the National Neonatal Screening Program tests for six diseases, with a new law issued in 2021 stating that it should incorporate more diseases, including SMA. In the present study, dried blood spot (DBS) samples collected by the Reference Services of Neonatal Screening of RS and SP, to perform the conventional test were also screened for SMA, using real-time PCR, with SALSA MC002 technique. A total of 40,000 samples were analyzed, enabling the identification of four positive cases of SMA, that were confirmed by MLPA. Considering our sampling, Brazil seems to have an incidence comparable to the described in other regions. This work demonstrated that the use of the MC002 technique in samples routinely collected for the conventional NBS program is suitable to screen for SMA in our conditions and can be included in the expansion of the neonatal screening programs.

Abstract Mucopolysaccharidosis type II (MPS II) is a rare genetic, multiorgan disease. Little information about the Brazilian context is available to date; thus, this descriptive subgroup analysis was conducted on Brazilian data from the Hunter Outcome Survey (HOS), including clinical characteristics among MPS II patients from Brazil. HOS is a global, multi-center, long-term, observational registry of patients with MPS II (NCT03292887). Variables related to organ system involvement, signs and symptoms, surgical procedures and survival among Brazilian patients were extracted from HOS database. Data from 153 Brazilian patients with MPS II were analyzed. Musculoskeletal (96.6%), abdomen/gastrointestinal (95.2%), neurological (88.7%), pulmonary (86.2%), and ear (81.3%) were the most frequently observed organ/systems involved. Regarding signs and symptoms, the most prevalent symptom was coarse facial features consistent with the disease (94.6%), followed by joint stiffness and limited function (89.3%), hernia (84.2%) and hepatomegaly (82.2%). Median survival time was 22.0 years, and the major cause of death was respiratory failure (31.8%). These data may be helpful to understand disease characteristics and to help improve the quality of MPS II patient care in Brazil.

Abstract The COVID-19 pandemic led to the reorganization of health care in several countries, including Brazil. Inborn Errors of Metabolism (IEM) are a group of rare and difficult to diagnose genetic diseases caused by pathogenic variants in genes that code for enzymes, cofactors, or structural proteins affecting different metabolic pathways. The aim of this study was to evaluate how COVID-19 affected the diagnosis of patients with IEM during the first year of the pandemic in Brazil comparing two distinct periods: from March 1st, 2019 to February 29th, 2020 (TIME A) and from March 1st, 2020 to February 28th, 2021 (TIME B), by the analysis of the number of tests and diagnoses performed in a Reference Center in South of Brazil. In the comparison TIME A with TIME B, we observe a reduction in the total number of tests performed (46%) and in the number of diagnoses (34%). In both periods analyzed, mucopolysaccharidoses (all subtypes combined) was the most frequent LD suspected and/or confirmed. Our data indicates a large reduction in the number of tests requested for the investigation of IEM and consequently a large reduction in the number of diagnoses caused by the COVID-19 pandemic leading to a significant underdiagnosis of IEM.

ABSTRACT Research on the genetics, epidemiology, and clinical manifestations of Fabry disease (FD) has increased significantly in recent years. However, some relevant clinical questions still need to be answered to develop better approaches to patient management. This review focuses on answering specific questions raised by Brazilian experts based on their experience in diagnosing and managing patients with FD. The questions are as follows: What is the role of globotriaosylsphingosine in diagnosis? How does one proceed with the diagnosis if there is a variant of unknown significance? What are the earliest and most reliable markers of renal, cardiac, and neurological impairment? What is the prevalence of FD in patients with cryptogenic stroke? What is the average delay in diagnosis in patients with FD? Based on these questions, our objective was to highlight epidemiological, diagnostic, and clinical aspects relating to the literature in the FD field.

Abstract Mucopolysaccharidoses (MPS) are rare inborn errors of metabolism, leading to the accumulation of glycosaminoglycans (GAG) in distinct tissues. We investigated oropharyngeal dysphagia using the videofluoroscopic swallowing study (VFSS) in patients with different MPS types. Since there is a lack of studies systematically evaluating this disorder in this population, the use of a standard technique should contribute to better evaluate individuals with MPS. A cross-sectional and observational study enrolling patients followed by an outpatient service for lysosomal diseases at the Genetics Service of the Hospital de Clínicas de Porto Alegre (SGM/HCPA) was conducted. Patients underwent semi-structured interviews, clinical evaluation and VFSS. Nineteen patients were evaluated, including patients with MPS types I (16%), II (42%), IIIb (10%) and IVa (32%). Nearly all patients (95%) presented with oropharyngeal dysphagia in the VFSS. The most frequent findings were impaired chewing during oral phase (94%) and reduced laryngeal elevation in the pharyngeal phase (72%). Oropharyngeal dysphagia constituted a prevalent symptom in the studied cohort regardless of MPS type. Our data reinforces the notion that this disorder should be objectively assessed since it can significantly compromise the nutrition and the hydration of these patients as well as lead to tracheobronchial aspiration, thus resulting in aspiration pneumonia and even death eventually.

Abstract The mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders caused by 11 enzyme deficiencies, classified into seven types. Data on the birth prevalence of each MPS type are available for only a few countries, and the totality of cases may be underestimated. To determine the epidemiological profile of MPS in each Brazilian region, we analyzed data collected between 1982 and 2019 by a national reference laboratory and identified 1,652 patients. Using data between 1994 and 2018, the birth prevalence (by 100,000 live births) for MPS was 1.57. MPS II was the most common type of MPS in Brazil, and its birth prevalence was 0.48 (0.94 considering only male births). Regarding the number of cases per region, MPS II was the most frequent in the North and Center-West (followed by MPS VI), and also in the Southeast (followed by MPS I); MPS I and MPS II were the most common types in the South; and MPS VI was the most common in the Northeast (followed by MPS II). The differences observed in the relative frequencies of MPS types across Brazilian regions are likely linked to founder effect, endogamy, and consanguinity, but other factors may be present and need further investigation.

Abstract Introduction: Gaucher disease (GD) is one of the common lysosomal storage disorder (LSD) with an estimated frequency of one in 40,000 newborns globally. GD is an autosomal recessive condition, which results from mutations in the GBA1 gene, causing partial or complete deficiency of β-glucocerebrosidase enzyme activity, which leads to the widespread accumulation of the substrate glucosylceramide. Aims: This report presents different challenges of clinical management and communication between medical specialties to reach diagnose of any rare disease in Mozambique, a low-income country, which health system has limited infrastructure, trained personnel, and budget for diagnosis and to provide treatment for rare genetic disorders such as GD. Case Presentation: The patient was a 15-year old black female patient of Mozambican nationality born from non-consanguineous parents. Three of the four patient’s siblings were healthy; one sister had died of a disease with a similar clinical features. Our patient presented with abdominal distention and hepatosplenomegaly. Blood tests revealed pancytopenia and a high level of ferritin. Liver biopsy and histologic examination revealed infiltration of the splenic parenchyma and portal area of the liver as well as enlarged histiocytic cells with granular cytoplasm. Magnetic resonance imaging showed liver enlargement, changes in the femoral heads without osteonecrosis, a pathological fracture of the third thoracic vertebrae (T3), with absence of brain and spinal cord neurological abnormalities. The biochemical investigation disclosed low levels of β-glucocerebrosidase (0.223 nmol/h/ml; normal: above 0.98) and increased levels of lyso-Gb1 (0.43 µg/ml; normal: up to 0.003). Genotyping of the GBA1 gene indicated the presence of the pathogenic variant p.Arg87Trp (R48W) in homozygosis. Discussion and Conclusion: To the best of our knowledge, this report describes the first case of GD type 1 confirmed via biochemical and molecular genetic testing in Mozambique. As awareness of the GD and rare genetic diseases among Mozambican health professionals is very limited, and resources for diagnosis are scarce in the national health system, it is possible that other cases remain undiagnosed in this low-income country.

Abstract Sanfilippo syndrome or mucopolysaccharidosis III (MPS III), includes a group of four autosomal recessive lysosomal storage disorders caused by deficient activity of enzymes involved in the catabolism of heparan sulfate. The four types of MPS III are recognized in accordance with the deficient enzyme, resulting in the accumulation of heparan sulfate with particularly deleterious effects in the central nervous system. The incidence of MPS III remains to be established in Latin American countries. We describe the journey of a patient with MPS IIIB whom, even in the presence of speech delay and deterioration, behavioral problems and motor incoordination, showed unaltered urinary glycosaminoglycans (GAGs) levels. An investigation for MPS was undertaken and enzyme analysis indicated a deficiency of alpha-N-acetylglucosaminidase, leading to the diagnosis of MPS IIIB. With the correct diagnosis, the patient’s symptoms could be properly managed, and the parents received appropriate genetic counseling. The present case report reinforces the need of investigating MPS III in patients with language delay and/or regression, neurological impairment and behavioral alterations, even when urinary GAGs are within normal range. A definitive diagnosis ends the diagnostic journey and enables the medical team and family to provide a better care for the child.

Abstract Neuronal ceroid lipofuscinoses (NCLs), also referred as “Batten disease”, are a group of thirteen rare genetic conditions, which are part of the lysosomal storage disorders. CLN type 2 (CLN2) is caused by the deficient activity of the tripeptidyl peptidase I (TPP1) enzyme, encoded by the TPP1 gene, most frequently leading to the classic late infantile phenotype. Nearly 140 CLN2-causing mutations have been described. In this case report, we describe the identification of a new disease-causing mutation and highlight the importance of appropriate laboratory investigation based on clinical suspicion. The collection of dried blood spots (DBS) on filter paper, which is a convenient sample, can be used to measure the TPP1 enzyme activity and detect CLN2-related mutations. Since the biochemical and genetic diagnoses are possible and as the disease progression is fast and the therapeutic window is short, the investigation of CLN2 should be always considered when this diagnostic hypothesis is raised in order to enable the patients to benefit from the specific pharmacological treatment.

Abstract Phenylketonuria (PKU) is caused by deficient activity of phenylalanine hydroxylase (PAH), responsible for the conversion of phenylalanine (Phe) to tyrosine (Tyr). Monitoring of patients with PKU requires the measurement of Phe in plasma using high-performance liquid chromatography (HPLC) or in dried blood spots (DBS) using different techniques to adjust treatment strategy. The objective of this study was to evaluate Phe levels in DBS measured by two different methods and compare them with Phe levels measured in plasma by HPLC. We analyzed 89 blood samples from 47 PKU patients by two different methods: fluorometric method developed in-house (method A) and the commercially available PerkinElmer® Neonatal Phenylalanine Kit (method B) and in plasma by HPLC. The mean Phe levels by method A, method B, and HPLC were 430.4±39.9μmol/L, 439.3±35.4μmol/L, and 442.2±41.6μmol/L, respectively. The correlation values between HPLC and methods A and B were 0.990 and 0.974, respectively (p < 0.001 for both). Our data suggest that methods A and B are useful alternatives for monitoring Phe levels in patients with PKU, with method A being in closer agreement with the reference standard (HPLC).

Abstract In Brazil, the population in general has little knowledge about genetic risks, as well as regarding the role and importance of the Cancer Genetic Counseling (CGC). The goal of this study was to evaluate cancer-related worry and cancer risk perception during CGC sessions in Brazilian women at-risk for hereditary breast cancer. This study was performed in 264 individuals seeking CGC for hereditary breast cancer. Both cancer-affected and unaffected individuals were included. As results, individuals with and without cancer reported different motivations for seeking CGC and undergoing genetic testing. A correlation was observed between age at the first CGC session and age at which the closest relative was diagnosed with cancer. Multivariate analysis showed that educational level, cancer risk discussion within the family, and number of deaths by cancer among first-degree relatives influenced positively the cancer risk perception. In conclusion, the results of this study indicate that cancer-related worry and cancer risk perception are significant aspects of morbidity in individuals seeking CGC, whether they are cancer-affected or unaffected. CGC has an important role in health education and cancer prevention for its potential of promoting an accurate perception of the risk.

Abstract Mucopolysaccharidosis III (MPS III) is a rare inherited metabolic disease primarily affecting the central nervous system, leading to developmental and/or speech regression. Early diagnosis of the disease is important to introduce appropriate management measures and to optimize therapeutic outcomes. The diagnosis of MPS III is often significantly delayed due to the rarity of the disease, the more attenuated somatic presentation compared to other MPS types, and the symptom overlap with other developmental disorders. To shorten the time to diagnosis, a list of eight early signs and symptoms was identified through an expert system approach by a global, multidisciplinary working group of 13 specialists with expertise in various aspects of MPS and developmental disorders and three parents of MPS III patients. Coarse facial features and persistent hirsutism or prominent, thick eyebrows were identified as the most important MPS III early signs. The list of eight early MPS III signs and symptoms is the first step towards the development of a clinical algorithm aiming to identify neonates and infants with MPS III before the onset of neurocognitive damage, ultimately shortening the diagnostic journey of MPS III patients.

Abstract Lysosomal storage disorders (LSDs) are a group of genetic disorders characterized by deficiency of specific lysosomal enzymes. In general, patients are clinically normal at birth, and progressively develop severe signs and symptoms. Diagnosis is usually made several years after onset of manifestations, preventing patients to have the benefits of the early treatment. Newborn screening programs are being considered for LSDs to allow early diagnosis and treatment. The present study evaluated the feasibility of a customized screening approach based on modified fluorometric assays with reduced amounts of reagents, substrates and samples for: mucopolysaccharidosis (MPS) type I (MPS I), MPS VI, Fabry, Gaucher, and Pompe diseases. We also evaluated the advantages of including blood chitotriosidase and urinary glycosaminoglycans in the protocol. By the measurement of the specific disease-associated enzymes (plus blood chitotriosidase and urinary glycosaminoglycans) we analyzed 834 de-identified DBS of unselected newborns. No positive case was detected, and the false-positive rates were low. Taking into consideration the limitations of this methodology, we believe that, after defining proper cutoffs, it could be a viable alternative to provide NBS for LSDs by laboratories that may not be able to afford the commercial methods available.

Abstract Mucopolysaccharidoses (MPS) constitute a heterogeneous group of rare genetic disorders caused by enzymatic deficiencies that lead to the accumulation of glycosaminoglycans (GAGs). Clinical observations suggest a health-related impairment in quality of life in patients with MPS. Professionals with extensive experience in the care of patients with inborn errors of metabolism, such as MPS, held a meeting in April 2017 to discuss and propose recommendations for the evaluation and management of quality of life in MPS patients in Latin America. In the light of this scenario, the present work summarizes the content of the discussions and presents the recommendations produced at the meeting. The panel had suggested the use of the following tools for the assessment of health-related quality of life (HRQoL): Children's Health Assessment Questionnaire (CHAQ) for children and patients unable to express their feelings, Health Assessments Questionnaire (HAQ) and EuroQol 5 Domains (EQ-5D) scales for adult patients. Based on the scores verified in these scales, the panel proposes interventions that aim reducing the impairment of the quality of life in patients with MPS disorders.

Abstract Lysosomal storage disorders (LSDs) constitute a heterogeneous group of approximately 50 genetic disorders. LSDs diagnosis is challenging due to variability in phenotype penetrance, similar clinical manifestations, and a high allelic heterogeneity. A powerful tool for the diagnosis of the disease could reduce the “diagnostic odyssey” for affected families, leading to an appropriate genetic counseling and a better outcome for current therapies, since enzyme replacement therapies have been approved in Brazil for Gaucher, Fabry, and Pompe diseases, and are under development for Niemann-Pick Type B. However, application of next-generation sequencing (NGS) technology in the clinical diagnostic setting requires a previous validation phase. Here, we assessed the application of this technology as a fast, accurate, and cost-effective method to determine genetic diagnosis in selected LSDs. We have designed two panels for testing simultaneously 11 genes known to harbor casual mutations of LSDs. A cohort of 58 patients was used to validate those two panels, and the clinical utility of these gene panels was tested in four novel cases. We report the assessment of a NGS approach as a new tool in the diagnosis of LSDs in our service.