Abstract Cystic fibrosis (CF) is an autosomal recessive disorder and is caused by variants in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. We aimed to study the frequency of the F508del variant, the most common variant worldwide, in patients with CF from Paraguay. The frequency of the F508del variant in Paraguayan patients with a clinical diagnosis of CF was assessed using a polymerase chain reaction followed by the sequencing of the PCR products. 43 of the 86 patients (50%) were homozygous for the F508del variant, 28 were heterozygous (32.56%), and the remaining 15 (17.44%) were non-carriers. In terms of alleles, there were 114 mutated (114/172 or 66.28%) and 58 did not correspond to this variant (58/172 or 33.72%). This is the first study of the frequency of the F508del variant in patients with CF in Paraguay. This information is of utmost relevance when planning and offering treatments from health services.

Abstract Mucopolysaccharidosis (MPS) is a group of metabolic disorders caused by the deficiency or complete absence of certain lysosomal enzymes responsible for the breakdown of mucopolysaccharides, causing an accumulation of glycosaminoglycans (GAGs) throughout the body. Mucopolysaccharidosis type I (MPS I), also called Hurler syndrome, is an autosomal recessive lysosomal storage disorder resulting from a deficiency of the enzyme α-L-iduronidase. This report aims to present the clinical findings and diagnosis of a 21-month-old female with no history of similar cases in their previous generations. The diagnosis was considered based on the clinical and radiological characteristics of Hurler syndrome (HS) and confirmed biochemically, becoming the first confirmed case in the Dominican Republic.

Abstract We aimed to characterize the clinical spectrum of patients diagnosed with SRD5A3-CDG, a subtype of congenital disorders of glycosylation (CDG) due to variants in the steroid 5a-reductase type 3 (SRD5A3) gene. It presents with multi-systemic involvement including neurological disability, dermatologic abnormalities, and ophthalmological defects. We conducted a cross-sectional study of children (n=6, ages 4-16 years) with a confirmed diagnosis of SRD5A3-CDG (c.57G>A, p.W19X). Families completed a detailed medical history questionnaire, two quality of life measures, and an adaptive behavior scale. Prevalent clinical features in our cohort included visual impairment (6/6), developmental delay (6/6), nystagmus (5/6), retinal dystrophy (4/6), and hypotonia (3/6). The Vineland Adaptive Behavior Scales demonstrated deficits across all functional domains (Composite Mean 36.17 ± 26.88), although one child did not show significant deficits. The QI-Disability Form demonstrated a mean total score of 64.8 (±12.7), and the PedsQL-Family Impact Module demonstrated a mean total score of 56.5 (±31.5). Vineland composite scores did not correlate with levels of disability captured by the QI-Disability Form (Pearson Correlation range -0.63 to +0.69, p>0.05 on all subscales). Ultimately, despite genotypic homogeneity, there is notable variability in adaptive functioning and quality of life among affected children that does not correlate with age.

ABSTRACT In Cuba, newborn screening (NBS) for cystic fibrosis (CF) was introduced in January 2019. The results from the first three years of the CF NBS program are presented. An IRT/IRT protocol was followed using a cut-off value of 50 ng/mL. In this period 281,717 neonates were screened, 2,197 samples had increased IRT values, and a second sample was necessary (recall rate=0.78%). In 686 (0.24%) neonates, IRT was still elevated, and they were referred for clinical evaluation. Twenty-one children were confirmed by sweat test and molecular biology. Eighteen newborns presented variant F508del. A false negative case was reported. Demographic data of 32,764 neonates were collected. The average age of sampling was six days with results available at 11 days of life, but 1.7% of the samples were collected 20 days after birth. The mean IRT value was 12.7±11.7 ng/mL (ranging 0-283 ng/mL) with a calculated 98.5 percentile value of 42.4 ng/mL. On average, the samples were processed five days after collection and two days after they were received at the laboratory. Although CF NBS program in Cuba is just beginning, it can be predicted that CF will be one of the most frequent inherited-metabolic diseases in the Cuban population.

Abstract The familial chylomicronemia syndrome (FCS) is characterized by very high levels of circulating triglycerides. FCS is caused by lipoprotein lipase (LPL) deficiency resulting from homozygous or biallelic loss-of-function variants in the LPL or other related genes. Here, we report a case of severe hypertriglyceridemia refractory to conventional therapy in a male patient diagnosed at 33 years of age. LPL activity was below 20%. During the clinical course, the patient developed severe acute pancreatitis in addition to other complications. Two heterozygous variants (c.984G>A and c.1139+6T>C) which had not been previously reported in the major databases were identified in the LPL gene. Treatment with volanesorsen was proposed based on its approved indication as an adjunct to diet in adult patients with confirmed FCS and at high risk for pancreatitis. Volanesorsen was effective and well-tolerated, and the patient did not experience abdominal pain or any other manifestations. The assessment of genetic characterization is essential to guide treatment decisions during follow-up, in addition to the patient’s history, their comorbidities and clinical stigmas.

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 Aromatic L-Amino acid decarboxylase (AADC) deficiency is a rare neurometabolic disorder due to a homozygous or compound heterozygous pathogenic variant of the DDC gene, resulting in low synthesis of the biogenic amines dopamine, serotonin, epinephrine, and norepinephrine. Most patients had severe expression of the disease with global developmental delay, early hypotonia, movement disorders such as oculogyric crises, tremor, and dystonia. Oromandibular dystonia (OMD) is rarely recognized in patients with AADC deficiency. The aim of this study was to describe OMD in detail in 4 patients with AADC deficiency. OMD occurred in isolated form or in association with oculogyric crises, increasing the difficulty in care patients during the crises. The main form of OMD was tongue dystonia associated with mouth opening dystonia. AADC deficiency must be included in the list of genetic causes of OMD.

Abstract Data on Mucopolysaccharidosis type II (MPS II) in Latin America are scarce. This retrospective database study, using data from the Informatics Department of the Brazilian Health System (DATASUS), aimed to estimate the prevalence of MPSII in Brazil from 2008 to 2020 and to describe demographic and clinical profiles from patients under treatment. The study population was derived from DATASUS records of MPS II (ICD-10 E76.1) diagnosed in Brazil. Initially 455 patients were found, but only 181 patients who were receiving idursulfase treatment were included in this study. Among these cases, as expected in a X-linked disease, all were males and 40% of the cases were recorded in the Southeast region, and another 34% in the Northeast region. The biggest proportion of patients (39%) were diagnosed when they were 10-19 years old. There are 212 clinical conditions associated with MPS II, although the main comorbidities related to MPSII include: abdominal/inguinal hernia, respiratory complications, and carpal tunnel syndrome. Respiratory disorders were the fifth most frequent comorbidity recorded in these patients. The healthcare professionals in Brazil more involved in the diagnosis of MPS II were radiologists, followed by geneticists and cardiologists. Despite some limitations, DATASUS is a relevant database to provide information on rare diseases such as MPS II. Most cases were reported in southeast and northeast regions, respectively. This information is crucial to help design targeted public policies.

Abstract Congenital muscular dystrophies (CMDs) are inherited, progressive and heterogeneous muscle disorders. A group of CMDs are dystroglycanopathies, also called α-dystroglycanopathies, where there is an abnormal glycosylation of protein α-dystroglycan. Hypoglycosylation of α-DG results in different severities of congenital muscular dystrophies and they present with progressive muscle weakness and loss of motor functions. This article first focuses on the CMDs, their classification according to the observed symptoms or the protein involved in the resulting phenotype. We then focus on dystroglycanopathies, the importance of its correct O-glycosylation of the α-dystroglycan given its important structural function, considering the enzymes involved in said glycosylation and the phenotypes that can result, to finally address current therapeutics for these diseases with the aim of increasing current knowledge. (CMDs inherited disorders dystroglycanopathies αdystroglycanopathies, αdystroglycanopathies α α-dystroglycanopathies αdystroglycan. αdystroglycan dystroglycan. dystroglycan αDG DG functions phenotype Oglycosylation O function result knowledge

Abstract Screening newborns for genetic and other diseases is one of the most effective ways to improve health and reduce disease in a population. In developed countries, newborn screening has been a cornerstone of public health for decades. In many developing countries, however, newborn screening is still in its infancy. Many countries still lack screening programs. When a program is available, it generally lacks well-defined criteria on which decision-makers can justify the choice of diseases screened for and the methods used. One of the reasons put forward to understand this observation is the fact that little consideration is given by decision-makers to economic evaluations as a pillar of decision-making, as is the case in industrialized countries. This article provides a brief description of the challenges of using economic evaluation of newborn screening in developing countries. This will be illustrated by the example of the national newborn screening program in Vietnam. population decades however infancy programs available welldefined well defined decisionmakers decision makers used decisionmaking, decisionmaking making, making decision-making Vietnam

Abstract Fabry disease (FD) is an X-linked lysosomal storage disorder characterized by reduced or absent activity of the enzyme α-galactosidase A. Due to systemic accumulation of glycolipids, FD phenotype is diverse, and diagnosis may be challenging. Clinical manifestations include small fiber neuropathy, renal dysfunction, cardiac involvement, cerebrovascular disease, among others. In the present study, we describe biopsy proven small fiber neuropathy and subclinical cardiac involvement in two cousins diagnosed with FD secondary to a recently described pathogenic variant, highlighting the importance of diagnostic tools to document organ damage and allow early treatment. (FD Xlinked X linked αgalactosidase α galactosidase A glycolipids diverse challenging dysfunction others study variant treatment

Abstract Mucopolysaccharidosis IIIA (MPS IIIA) is a lysosomal storage disorder (LSD) caused by deficiency of lysosomal N-sulphoglucosamine sulphohydrolase, which is one of four enzymes involved in heparan sulfate degradation. Traditional methods used for MPS IIIA diagnostics usually constitute of selective screening, based on the analysis of urinary glycosaminoglycans, further enzymatic assays in leukocytes, and mutation analysis. Nowadays, some LSDs, including mucopolysaccharidoses, can be precisely diagnosed by mass spectrometry-based techniques. Up to this date, there are no comprehensive studies of MPS IIIA diagnostics by MALDI-TOF analysis of free oligosaccharides in urine published. In the presented work, MALDI-TOF/TOF analysis of permethylated oligosaccharides was performed to obtain the set of glyco-biomarkers that together form the specific fingerprint of this disease. Early and accurate diagnostics of MPS IIIA is crucial to stabilize the progressive cellular damage and improve the overall well-being of patients. LSD (LSD Nsulphoglucosamine N sulphoglucosamine sulphohydrolase degradation screening glycosaminoglycans leukocytes Nowadays LSDs mucopolysaccharidoses spectrometrybased spectrometry techniques date MALDITOF MALDI TOF published work MALDITOF/TOF MALDITOFTOF TOF/TOF glycobiomarkers glyco biomarkers disease wellbeing well being patients TOFTOF

Abstract Classical galactosemia is caused by the genetic deficiency of galactose-1-phosphate-urydyl-transferase resulting in clinical symptoms development during the first weeks of life including jaundice, hypotonia, lethargy, emesis, hepatomegaly, among others. Currently, dietary restriction of galactose is considered the standard for classical galactosemia management. For several years, severe dietary galactose restriction was considered necessary, implying restriction not only of dairy products, but also fruits, vegetables, legumes, and viscera. Such management failed to improve or prevent the appearance of long-term complications, by contrast, such restrictive approach may lead to nutritional deficiencies development. Thus, the last consensus suggests guidelines that are more flexible. In addition, the lack of knowledge regarding the physiopathology of the disease, and the toxicity threshold of the metabolites accumulated, make even more difficult to propose novel and more effective therapeutic approaches. This review summarizes the current state of knowledge regarding classical galactosemia in terms of physiopathology, long-term complications, newborn screening and genetic variants and their implications on galactosemia treatment, summed to the challenges that researchers working on this disease must address in future studies including the analysis of galactose content in foods, galactose tolerance threshold and search for novel therapeutic targets.

Abstract Introduction Mucopolysaccharidoses (MPS) can lead to cervical spinal cord compression (SCC). Diagnostic scores for SCC in MPS use the obliteration of the passage of cerebrospinal fluid in the anterior and posterior spinal cord in the sagittal section of magnetic resonance imaging (MRI). The spinal cord occupation ratio (SCOR) published, by Nouri et al (2018), establishes the spinal cord filling index for the spinal cord, identifying disproportionate spinal cord occupation in the canal. When evaluating congenital canal stenosis, the risk of spinal cord injury has been considered increased when the SCOR is ≥70% in the median sagittal plane or ≥ 80% in the axial plane. Although these values have not been validated for MPS populations, they could be useful. Objective To verify the SCOR in MPS patients with diagnosis of cervical SCC comparing the SCOR with other markers proposed in the existing MPS SCC scores, such as the extent of gliosis, clinical impact and the SCC assessment as represented by the obliteration of CSF flow. Methods We reviewed imaging tests of the cervical spine from MPS patients with previously confirmed SCC, using the SCOR measure in the median sagittal plane, evaluation of the presence and extent of spinal gliosis on MRI, evaluation of the clinical impact using a clinical score and evaluation of the images for the obliteration of cerebral spinal fluid (CSF) flow. Results Thirty-one MRI of 24 different patients were included. The average SCOR was 87.1%. This was lower (81.6%) in patients without gliosis, when compared to those with focal (90.5%) and extensive (97%) gliosis. The only patient with gliosis associated with a lacunar lesion, resulting from an acute compressive injury, had a 68% SCOR, due to the atrophic spinal cord injury. As expected, SCOR was higher in patients with total or partial CSF obliteration, but one among the 3 patients without CSF flow obliteration, with a 76% SCOR, had already developed focal gliosis and mild clinical abnormalities. Patients with more extensive gliosis had higher clinical scores. Four patients had more than one imaging scan evaluated. SCOR upward trend showed an annual average increase of 3.8%. Discussion & Conclusions The use of SCOR allows the diagnosis of cervical spinal canal stenosis in an objective way. It is possible that the cut-off values used by Nouri et al in patients with congenital stenosis could be useful to diagnose cervical stenosis in MPS patients, preceding the finding of CSF flow obstruction, presence of gliosis or clinical abnormalities. Furthermore, the use of SCOR may assist in the longitudinal evaluation of disease progression. Better follow-up and timely diagnosis allows for scheduling of surgery at the best clinical moment, minimizing complications.

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.