Lysosomal storage diseases (LSDs) are genetic disorders, clinically heterogeneous, mainly caused by defects in genes encoding lysosomal enzymes that degrade macromolecules. Several LSDs already have specific therapies that may improve clinical outcomes, especially if introduced early in life. With this aim, screening methods have been established and newborn screening (NBS) for some LSDs has been developed. Such programs should include additional procedures for the confirmation (or not) of the cases that had an abnormal result in the initial screening. We present here the methods and results of the additional investigation performed in four babies with positive initial screening results in a program of NBS for LSDs performed by a private laboratory in over 10,000 newborns in Brazil. The suspicion in these cases was of Mucopolysaccharidosis I - MPS I (in two babies), Pompe disease and Gaucher disease (one baby each). One case of pseudodeficiency for MPS I, 1 carrier for MPS I, 1 case of pseudodeficiency for Pompe disease and 1 carrier for Gaucher disease were identified. This report illustrates the challenges that may be encountered by NBS programs for LSDs, and the need of a comprehensive protocol for the rapid and precise investigation of the babies who have an abnormal screening result.
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.
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 1
st
, 2019 to February 29
th
, 2020 (TIME A) and from March 1
st
, 2020 to February 28
th
, 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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.