Disease progression in Sanfilippo type B: Case series of Brazilian patients.

Mucopolysaccharidosis type IIIB (MPS IIIB) is caused by deficiency of alpha-N-acetylglucosaminidase, leading to storage of heparan sulphate. The disease is characterized by intellectual disability and hyperactivity, among other neurological and somatic features. Here we studied retrospective data from a total of 19 MPS IIIB patients from Brazil, aiming to evaluate disease progression. Mean age at diagnosis was 7.2 years. Speech delay was one of the first symptoms to be identified, around 2-3 years of age. Behavioral alterations include hyperactivity and aggressiveness, starting around age four. By the end of the first decade, patients lost acquired abilities such as speech and ability to walk. Furthermore, as disease progresses, respiratory, cardiovascular and joint abnormalities were found in more than 50% of the patients, along with organomegaly. Most common cause of death was respiratory problems. The disease progression was characterized in multiple systems, and hopefully these data will help the design of appropriate clinical trials and clinical management guidelines.

Clusters of rare disorders and congenital anomalies in South America.

Objective: To map geographic clusters of rare disorders and congenital anomalies reported in South America. Methods: Qualitative systematic review conducted in Medline/PubMed, Lilacs, and Scielo electronic databases to identify studies meeting eligibility criteria. The strategy resulted in 1 672 unique articles, from which 164 were selected for full reading by a pair of reviewers. Results: Fifty-five articles reported at least one cluster of genetic disorders or congenital anomalies in South American territory. From these papers, 122 clusters were identified, of which half (61) were related to autosomal recessive disorders. Sixty-five (53.3%) of the clusters were located in Brazil. Conclusions: The results of the review reinforce that rare diseases and congenital anomalies can occur in a non-random way in space, which is discussed in the perspective of the complex history of formation, social organization, and genetic structure of the South American population. Mapping clusters in population medical genetics can be an important public health tool, given that such places concentrate cases of rare diseases that frequently require multiprofessional, specialized care. Therefore, these results can support important agendas in public health related to rare diseases and congenital anomalies, such as health promotion and surveillance.

Clusters of oculocutaneous albinism in isolated populations in Brazil: A community genetics challenge.

Oculocutaneous albinism (OCA) is a heterogeneous group of genetic disorders involving deficiencies in melanin biosynthesis, with consequent skin, hair, and eye hypopigmentation. The world prevalence is estimated at 1/17,000, but there is high variability among populations. The affected individuals, besides clinical complications, can suffer from discrimination. The Brazilian population is highly admixed, with isolated and inbred communities. Previous reports indicated the presence of diverse isolated communities with a high prevalence of OCA in Brazil. The present work sought to review and characterize clusters of albinism in this country based on scientific literature search, newspapers, and websites. We identified and characterized 18 clusters, 13 confirmed by scientific studies. Seven clusters are in the Northeast region, with predominant African ancestry, and seven others in indigenous communities, particularly among the Kaingaing in South Brazil. Isolation and inbreeding associated with founder effects seem to be the most plausible explanation. Molecular studies and clinical classification are still limited. Their localization in deprived regions with poor infrastructure makes them particularly vulnerable to the social and clinical consequences of lacking melanin. We reinforce the need for a tailored approach to these communities, including appropriate medical care, social support, and genetic counselling.

Sanfilippo syndrome type B: Analysis of patients diagnosed by the MPS Brazil Network.

Mucopolysaccharidosis type IIIB is a rare autosomal recessive disorder characterized by deficiency of the enzyme N-acetyl-alpha-d-glucosaminidase (NAGLU), caused by biallelic pathogenic variants in the NAGLU gene, which leads to storage of heparan sulfate and a series of clinical consequences which hallmark is neurodegeneration. In this study clinical, epidemiological, and biochemical data were obtained from MPS IIIB patients diagnosed from 2004-2019 by the MPS Brazil Network ("Rede MPS Brasil"), which was created with the goal to provide an easily accessible and comprehensive investigation of all MPS types. One hundred and ten MPS IIIB patients were diagnosed during this period. Mean age at diagnosis was 10.9 years. Patients were from all over Brazil, with a few from abroad, with a possible cluster of MPS IIIB identified in Ecuador. All patients had increased urinary levels of glycosaminoglycans and low NAGLU activity in blood. Main clinical symptoms reported at diagnosis were coarse facies and neurocognitive regression. The most common variant was p.Leu496Pro (30% of alleles). MPS IIIB seems to be relatively frequent in Brazil, but patients are diagnosed later than in other countries, and reasons for that probably include the limited awareness about the disease by health professionals and the difficulties to access diagnostic tests, factors that the MPS Brazil Network is trying to mitigate.

Genotype-phenotype studies in a large cohort of Brazilian patients with Hunter syndrome.

Mucopolysaccharidosis type II (MPS II) is an X-linked inherited disease caused by pathogenic variants in the IDS gene, leading to deficiency of the lysosomal enzyme iduronate-2-sulfatase and consequent widespread storage of glycosaminoglycans, leading to several clinical consequences, with progressive manifestations which most times includes cognitive decline. MPS II has wide allelic and clinical heterogeneity and a complex genotype-phenotype correlation. We evaluated data from 501 Brazilian patients diagnosed with MPS II from 1982 to 2020. We genotyped 280 of these patients (55.9%), which were assigned to 206 different families. Point mutations were present in 70% of our patients, being missense variants the most frequent. We correlated the IDS pathogenic variants identified with the phenotype (neuronophatic or non-neuronopathic). Except for two half-brothers, there was no discordance in the genotype-phenotype correlation among family members, nor among MPS II patients from different families with the same single base-pair substitution variant. Mothers were carriers in 82.0% of the cases. This comprehensive study of the molecular profile of the MPS II cases in Brazil sheds light on the genotype-phenotype correlation and helps the better understanding of the disease and the prediction of its clinical course, enabling the provision of a more refined genetic counseling to the affected families.

An invincible memory: what surname analysis tells us about history, health and population medical genetics in the Brazilian Northeast.

Several studies have shown that the Brazilian Northeast is a region with high rates of inbreeding as well as a high incidence of autosomal recessive diseases. The elaboration of public health policies focused on the epidemiological surveillance of congenital anomalies and rare genetic diseases in this region is urgently needed. However, the vast territory, socio-demographic heterogeneity, economic difficulties and low number of professionals with expertise in medical genetics make strategic planning a challenging task. Surnames can be compared to a genetic system with multiple neutral alleles and allow some approximation of population structure. Here, surname analysis of more than 37 million people was combined with health and socio-demographic indicators covering all 1794 municipalities of the nine states of the region. The data distribution showed a heterogeneous spatial pattern (Global Moran Index, GMI = 0.58; p < 0.001), with higher isonymy rates in the east of the region and the highest rates in the Quilombo dos Palmares region - the largest conglomerate of escaped slaves in Latin America. A positive correlation was found between the isonymy index and the frequency of live births with congenital anomalies (r = 0.268; p < 0.001), and the two indicators were spatially correlated (GMI = 0.50; p < 0.001). With this approach, quantitative information on the genetic structure of the Brazilian Northeast population was obtained, which may represent an economical and useful tool for decision-making in the medical field.

Population medical genetics: translating science to the community.

Rare genetic disorders are currently in the spotlight due to the elevated number of different conditions and significant total number of affected patients. The study of these disorders is extremely helpful for the elucidation of physiological processes related with complex disorders. Isolated populations are instrumental for the study of genetic disorders, considering their homogeneity and high proportion of affected patients in a small geographic area. These favorable conditions lead to the creation of a new discipline, known as "population medical genetics", which integrates medical genetics, population genetics, epidemiological genetics and community genetics. In order to develop practical activities in this new discipline, the National Institute of Population Medical Genetics (INaGeMP) was created in 2008 in Brazil. INaGeMP has developed several tools and funded numerous research activities. In this review, we highlight three successful projects developed in the first 10 years of INaGeMP activities (2008-2018): a newborn screening pilot study for MPS VI in Northeast Brazil, the study of Machado-Joseph disease in Brazilian families with Azorian ancestry, and the high twinning rate in a small town in southern Brazil. The results of these projects in terms of scientific output and contributions to the affected communities highlight the success and importance of INaGeMP.

Lack of association between genetic polymorphisms in IGF1 and IGFBP3 with twin births in a Brazilian population (Cândido Godói, Rio Grande do Sul).

Insulin-like growth factor (IGF-1) is an important peptide hormone involved in the reproduction and fetal development of mammals, and it is suggested that it may influence the human twinning rate. This study aimed to test such possible association, investigating the genetic polymorphisms IGF1 (CA)n and IGFBP3 rs2854744 in the population from Candido Godoi (CG), a small city located in the South of Brazil that has a high prevalence of twin births. A case-control study was performed comprising a total of 39 cases (representing about 40% of the mothers of twins who were born in CG after 1995) and 214 controls (mothers of non-twin children), 97 of whom were living in CG while 117 were living in Porto Alegre. DNA was extracted from blood leucocytes and genotyping was performed. According to the statistical analyses, there was no significant difference in the frequencies of both studied genetic polymorphisms when comparing case group with control group. Thus, our results pointed to a lack of association between IGF1 (CA)n and IGFBP3 rs2854744 polymorphisms and twin births in CG, but further investigations in other populations with different characteristics must be performed to confirm the role of IGF-I in human twinning.

The importance of geographic and sociodemographic aspects in the characterization of mucopolysaccharidoses: a case series from Ceará state (Northeast Brazil).

Geographic and sociodemographic aspects may influence the natural history and epidemiology of mucopolysaccharidoses (MPS). The main objective in this work was to evaluate the clinical, molecular, and geographic profile of MPS in a population from Ceará (Northeast Brazil). For this, we have performed a descriptive cross-sectional study based on clinical evaluation, interviews with patients and/or family members, and review of medical records of 76 MPS patients. MPS II was the most common type, with the most affected individuals presenting missense pathogenic variants. Patients with MPS I proved to be the most severe clinical phenotype, presenting the first symptoms (mean: 7.1 months; SD = 4.5) and being diagnosed earlier (2.2 years; SD = 2.1) in comparison with the other types. In addition, we have shown that 13 individuals with MPS VI were born of consanguineous marriages in small, nearby cities, in a place where geographical isolation, consanguinity, and clusters of genetic diseases were previously reported. Ten of these individuals (at least, seven different families) presented a rare pathogenic variant in the ARSB gene, c.1143-8T > G in homozygosity, previously reported only among Iberian and South American patients. The results presented here provide a comprehensive picture of MPS in an important state of the Brazilian Northeast, a region that concentrates many risk factors for rare genetic diseases, such as endogamy, inbreeding, and reproductive isolation. We discuss the possible evolutionary processes and biosocial dynamics that can help to explain this finding in terms of population medical genetics and public health.

Prevalence of congenital anomalies at birth among live births in the state of Maranhão from 2001 to 2016: temporal and spatial analysis.

OBJECTIVES: To analyze the prevalence at birth and the spatial and temporal distribution of congenital anomalies (CAs) among live births in the state of Maranhão in 2001 to 2016. To describe demographic, gestational and neonatal variables of interest. METHODS: Ecological, population-based study, using secondary data from the Live Birth Information System (SINASC). Annual prevalence of total and per-group CAs was calculated. Spatial analyzes were based on the Local Indicators of Spatial Association (LISA) and the Moran I Index, and interactive maps were generated. Demographic, gestational and neonatal variables of interest available from SINASC were described in the group of newborns with CAs. RESULTS: 1,831,830 live births, 6,110 with CAs (33.4/10,000) were included. Higher frequencies occurred in more recent years. Spatial clusters have been observed in specific years. The prevalence of newborns with CAs was different between categories of variables considered as risk factors for this outcome. CONCLUSION: The prevalence at birth of total CAs was lower than expected for major human defects (3%). The temporal peak of records in 2015/2016 is probably related to the increase in CAs caused by gestational infection by the Zika virus. The spatial clusters were probably due to variations at random due to the small number of births as they are not repeated in other years. Studies like this are the basis for the establishment of CA surveillance programs.

National congenital anomaly registers in the world: historical and operational aspects. / Registros nacionais de anomalias congênitas no mundo: aspectos históricos e operacionais.

OBJECTIVE: To identify registers of congenital anomalies with national coverage currently available around the world, highlighting their main historical and operational characteristics. METHODS: This was a documentary study by means of a Medline database search (via PubMed) and searches involving reports, official documents and websites. Studies reporting at least one national registry were included. RESULTS: 40 registers of national congenital anomalies were identified in 39 different countries. All registers included in the study were concentrated in upper-middle or high-income countries located in Europe. Most of the registers were population-based, compulsory notification and with a time limit for notification of up to 1 year of age. The Brazilian register showed the highest annual coverage. CONCLUSION: The registers analyzed showed different characteristics, related to the reality of each country. The results presented provide support for the theme of congenital anomalies surveillance, especially in places where such activity is intended to be implemented.

List of priority congenital anomalies for surveillance under the Brazilian Live Birth Information System. / Lista de anomalias congênitas prioritárias para vigilância no âmbito do Sistema de Informações sobre Nascidos Vivos do Brasil.

OBJECTIVE: To define the list of priority congenital anomalies for improving their recording on the Brazilian Live Birth Information System (Sinasc). METHODS: Based on the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10), international protocols and meetings with specialists, the list of priority anomalies was built considering two main criteria: being diagnosable at birth and having intervention available at different levels. The list was submitted for consideration by the Brazilian Medical Genetics and Genomics Society. RESULTS: The list comprised eight groups of congenital anomalies distributed according to the type of related anomaly, as well as the affected part of the body and its corresponding code in ICD-10 Chapter XVII. CONCLUSION: The list of priority congenital anomalies for notification provides a basis for improving case recording on Sinasc.

Genetic variants linked to folliculogenesis and successful pregnancy are not associated with twin births in a twins' town.

Background: Cândido Godói (CG) is a small city in South Brazil in which natural twin births (both monozygotic and dizygotic) occur at an unusually high rate and the twin trait runs through the local families, which are mostly European descendants. We have argued that a genetic founder effect must have occurred during the settlement of CG and that genetic factors may help to explain the familial aggregation of twinning in that city.Objective: The aim of this study was to evaluate single nucleotide polymorphisms (SNPs) related to folliculogenesis (rs6166:C > T in FSHR, rs11031006:G > A near FSHB, and rs17293443:T > C in SMAD3) and successful pregnancies (rs2010963:C > G in VEGFA, rs1800629:G > A in TNF, rs1801131:T > G and rs1801133:G > A in MTHFR) in mothers from CG.Study design: Forty-four mothers of twins (the case group) and 102 mothers of singletons (the control group) from CG were investigated. Genotypes were determined using real-time PCR (TaqMan® SNP Genotyping Assay).Results: For all SNPs, the distributions of the genotypic and allelic frequencies were similar between cases and controls. Interestingly, a deviation from the Hardy-Weinberg equilibrium was detected for SNP rs11031006:G > A near FSHB in the control population. Different combinations of risk alleles and haplotypic analyses were homogeneously distributed between cases and controls.Conclusion: These results suggest a lack of association between the seven studied SNPs and twin births in CG. However, we hypothesized that other genetic variants related to folliculogenesis or successful pregnancies may be involved in this phenomenon. Identifying such genetic components may be important not only for the Brazilian "Twins' Town" but also for a better understanding of twinning in general.

A large family with CYLD cutaneous syndrome: medical genetics at the community level.

Germline mutations in the cylindromatosis gene (CYLD) are associated with a rare autosomal dominant disease known as CYLD cutaneous syndrome (CCS). Patients present multiple neoplasms originating from skin appendages. Here, we investigated the main clinical and molecular features of a large family with CCS having lived in a small Brazilian town for 6 generations, making its prevalence significantly high. We observed a predominance of the disease among males and a wide phenotypic variation. A high frequency of basal cell carcinomas among affected people was found. The mutation c.2806C>T, p.Arg936* in the CYLD gene was detected in all patients. In this work, a geographical cluster of CCS was found, which raised some community genetics issues related not only to the high prevalence of a rare disease in a limited area but also to the strong social stigma associated with the disease.

COVID-19 in Brazil: evolution of the epidemic up until epidemiological week 20 of 2020. / COVID-19 no Brasil: evolução da epidemia até a semana epidemiológica 20 de 2020.

Objective to describe the evolution of COVID-19 in Brazil up until epidemiological week 20 of 2020. Methods this is an ecological study based on data and official documents from the Brazilian Ministry of Health and international organizations; comparisons were made between Brazil and other countries and incidence and mortality rates were calculated. Results by the end of epidemiological week 20, 233,142 cases, and 15,633 deaths had been confirmed for Brazil as a whole and 3,240 (58.2%) of the country's municipalities had reported at least one case; Brazil was at an earlier phase of the pandemic when compared to other countries, except Russia and Turkey, regarding cumulative cases, and except Canada regarding cumulative deaths; the highest rates were found in Brazil's Northern Region states, where Amazonas state had the highest incidence rates(4,474.6/1,000,000) and mortality rates (331.8/1,000,000). Conclusion Brazil is one of the countries with the highest number of confirmed cases and deaths, with marked regional differences.

COVID-19 epidemic in Brazil: Where are we at?

OBJETIVE: To analyze the trends of COVID-19 in Brazil in 2020 by Federal Units (FU). METHOD: Ecological time-series based on cumulative confirmed cases of COVID-19 from March 11 to May 12. Joinpoint regression models were applied to identify points of inflection in COVID-19 trends, considering the days since the 50th confirmed case as time unit. RESULTS: Brazil reached its 50th confirmed case of COVID-19 in 11 March 2020 and, 63 days after that, on May 12, 177,589 cases had been confirmed. The trends for all regions and FU are upward. In the last segment, from the 31st to the 63rd day, Brazil presented a daily percentage change (DPC) of 7.3% (95%CI= 7.2;7.5). For the country the average daily percentage change (ADPC) was 14.2% (95%CI: 13.8;14.5). The highest ADPC values were found in the North, Northeast and Southeast regions. CONCLUSIONS: In summary, our results show that all FUs in Brazil present upward trends of COVID-19. In some FUs, the slowdown in DPC in the last segment must be considered with caution. Each FU is at a different stage of the pandemic and, therefore, non-pharmacological measures should be adopted accordingly.

International collaboration networks for the surveillance of congenital anomalies: a narrative review. / Redes internacionais de colaboração para a vigilância das anomalias congênitas: uma revisão narrativa.

Objective to identify international congenital anomaly surveillance collaboration networks, to list the programs that compose them and to compare their main characteristics. Methods this was a narrative literature review by means of a MEDLINE database search (via PubMed) and searches involving websites, reports and official documents. Results six international congenital anomaly surveillance collaboration networks were identified (ECLAMC, ICBDSR, EUROCAT, BINOCAR, SEAR-NBBD and ReLAMC), comprised of 98 programs present in 58 different countries on all continents, except Africa; the main characteristics regarding type of surveillance, coverage and location were discussed in a comparative manner. Conclusion international collaborative networks are important players for congenital anomaly surveillance, contributing to the understanding of the global epidemiological scenario of these conditions, in addition to acting both to strengthen individual existing programs and also to create surveillance initiatives in unassisted regions.

Congenital anomalies from the health surveillance perspective: compilation of a list based on ICD-10. / Anomalias congênitas na perspectiva da vigilância em saúde: compilação de uma lista com base na CID-10.

OBJECTIVE: To propose a list of congenital anomalies having corresponding codes in the International Statistical Classification of Diseases and Related Health Problems, 10thRevision (ICD-10), with the aim of applying it in health surveillance. METHODS: In December 2019, the following data sources were searched: ICD-10; ICD-11; anomalies monitored by three surveillance programs; and a database of rare diseases (Orphanet). Anomalies were retrieved from these data sources, processed to check for correspondence with ICD-10 and reviewed manually to compile the list. RESULTS: 898 codes were identified, of which 619 (68.9%) were contained in ICD-10 Chapter XVII. Of the 279 codes contained in other chapters, 19 were exclusive to the ICD-11 search, 72 to the surveillance programs, 79 to Orphanet and 36 to the search for terms in ICD-10. CONCLUSION: The codes contained in ICD-10 Chapter XVII do not capture the totality of congenital anomalies, indicating the need to adopt an expanded list.

Clusters of rare disorders and congenital anomalies in South America

[ABSTRACT]. Objective. To map geographic clusters of rare disorders and congenital anomalies reported in South America. Methods. Qualitative systematic review conducted in Medline/PubMed, Lilacs, and Scielo electronic data- bases to identify studies meeting eligibility criteria. The strategy resulted in 1 672 unique articles, from which 164 were selected for full reading by a pair of reviewers. Results. Fifty-five articles reported at least one cluster of genetic disorders or congenital anomalies in South American territory. From these papers, 122 clusters were identified, of which half (61) were related to autoso- mal recessive disorders. Sixty-five (53.3%) of the clusters were located in Brazil. Conclusions. The results of the review reinforce that rare diseases and congenital anomalies can occur in a non-random way in space, which is discussed in the perspective of the complex history of formation, social organization, and genetic structure of the South American population. Mapping clusters in population medical genetics can be an important public health tool, given that such places concentrate cases of rare diseases that frequently require multiprofessional, specialized care. Therefore, these results can support important agendas in public health related to rare diseases and congenital anomalies, such as health promotion and surveillance.

[RESUMEN]. Objetivo. Trazar los conglomerados geográficos de los trastornos y las malformaciones congénitas poco frecuentes notificados en América del Sur. Métodos. Se realizó una revisión sistemática cualitativa en las bases de datos electrónicas Medline/PubMed, Lilacs y Scielo para encontrar los estudios que cumplieran con los criterios de selección. Se encontraron 1672 artículos originales, de los que se seleccionaron 164 para su lectura completa por un par de revisores. Resultados. En 55 artículos se informó de al menos un conglomerado de trastornos genéticos o malforma- ciones congénitas en América del Sur. A partir de estos artículos, se encontraron 122 conglomerados, de los cuales la mitad (61) se asociaron con trastornos autosómicos recesivos. Sesenta y cinco (53,3%) de los conglomerados se ubicaron en Brasil. Conclusiones. Los resultados de la revisión confirman que las enfermedades raras y las malformaciones congénitas pueden presentarse de una forma no aleatoria en el espacio, lo que se comenta desde la per- spectiva de la complejidad histórica del proceso de formación, organización social y estructura genética de la población de América del Sur. Definir geográficamente los conglomerados en la genética médica pobla- cional puede ser una importante herramienta de salud pública, ya que en esos lugares se concentran casos de enfermedades raras que suelen requerir una atención especializada y multidisciplinaria. Por lo tanto, estos resultados pueden servir de apoyo a importantes programas de salud pública relacionados con las enferme- dades raras y las malformaciones congénitas como, por ejemplo, la promoción de la salud y la vigilancia.

[RESUMO]. Objetivo. Mapear agrupamentos geográficos de doenças raras e anomalias congênitas relatados na América do Sul. Métodos. Revisão sistemática qualitativa realizada nas bases de dados eletrônicos Medline/PubMed, Lilacs e Scielo para identificar estudos que atendessem aos critérios de elegibilidade. A estratégia resultou em 1.672 artigos únicos, dos quais 164 foram selecionados para leitura completa por uma dupla de revisores. Resultados. Cinquenta e cinco artigos relataram pelo menos um agrupamento de distúrbios genéticos ou anomalias congênitas no território sul-americano. A partir desses artigos, foram identificados 122 agrupamen- tos, dos quais metade (61) estava relacionada a doenças autossômicas recessivas. Sessenta e cinco (53,3%) dos agrupamentos estavam localizados no Brasil. Conclusões. Os resultados da revisão reforçam a observação de que doenças raras e anomalias congênitas podem ocorrer de forma não aleatória no espaço, o que é discutido na perspectiva da complexa história de formação, organização social e estrutura genética da população sul-americana. O mapeamento de agrupa- mentos em genética médica populacional pode ser uma importante ferramenta de saúde pública, visto que esses locais concentram casos de doenças raras que frequentemente requerem atendimento multiprofissional especializado. Portanto, esses resultados podem apoiar importantes agendas de saúde pública relacionadas a doenças raras e anomalias congênitas, como a vigilância e a promoção da saúde.

Clusters of rare disorders and congenital anomalies in South America / Conglomerados de trastornos y malformaciones congénitas poco frecuentes en América del Sur / Agrupamentos de doenças raras e anomalias congênitas na América do Sul

ABSTRACT Objective. To map geographic clusters of rare disorders and congenital anomalies reported in South America. Methods. Qualitative systematic review conducted in Medline/PubMed, Lilacs, and Scielo electronic databases to identify studies meeting eligibility criteria. The strategy resulted in 1 672 unique articles, from which 164 were selected for full reading by a pair of reviewers. Results. Fifty-five articles reported at least one cluster of genetic disorders or congenital anomalies in South American territory. From these papers, 122 clusters were identified, of which half (61) were related to autosomal recessive disorders. Sixty-five (53.3%) of the clusters were located in Brazil. Conclusions. The results of the review reinforce that rare diseases and congenital anomalies can occur in a non-random way in space, which is discussed in the perspective of the complex history of formation, social organization, and genetic structure of the South American population. Mapping clusters in population medical genetics can be an important public health tool, given that such places concentrate cases of rare diseases that frequently require multiprofessional, specialized care. Therefore, these results can support important agendas in public health related to rare diseases and congenital anomalies, such as health promotion and surveillance.

RESUMEN Objetivo. Trazar los conglomerados geográficos de los trastornos y las malformaciones congénitas poco frecuentes notificados en América del Sur. Métodos. Se realizó una revisión sistemática cualitativa en las bases de datos electrónicas Medline/PubMed, Lilacs y Scielo para encontrar los estudios que cumplieran con los criterios de selección. Se encontraron 1672 artículos originales, de los que se seleccionaron 164 para su lectura completa por un par de revisores. Resultados. En 55 artículos se informó de al menos un conglomerado de trastornos genéticos o malformaciones congénitas en América del Sur. A partir de estos artículos, se encontraron 122 conglomerados, de los cuales la mitad (61) se asociaron con trastornos autosómicos recesivos. Sesenta y cinco (53,3%) de los conglomerados se ubicaron en Brasil. Conclusiones. Los resultados de la revisión confirman que las enfermedades raras y las malformaciones congénitas pueden presentarse de una forma no aleatoria en el espacio, lo que se comenta desde la perspectiva de la complejidad histórica del proceso de formación, organización social y estructura genética de la población de América del Sur. Definir geográficamente los conglomerados en la genética médica poblacional puede ser una importante herramienta de salud pública, ya que en esos lugares se concentran casos de enfermedades raras que suelen requerir una atención especializada y multidisciplinaria. Por lo tanto, estos resultados pueden servir de apoyo a importantes programas de salud pública relacionados con las enfermedades raras y las malformaciones congénitas como, por ejemplo, la promoción de la salud y la vigilancia.

RESUMO Objetivo. Mapear agrupamentos geográficos de doenças raras e anomalias congênitas relatados na América do Sul. Métodos. Revisão sistemática qualitativa realizada nas bases de dados eletrônicos Medline/PubMed, Lilacs e Scielo para identificar estudos que atendessem aos critérios de elegibilidade. A estratégia resultou em 1.672 artigos únicos, dos quais 164 foram selecionados para leitura completa por uma dupla de revisores. Resultados. Cinquenta e cinco artigos relataram pelo menos um agrupamento de distúrbios genéticos ou anomalias congênitas no território sul-americano. A partir desses artigos, foram identificados 122 agrupamentos, dos quais metade (61) estava relacionada a doenças autossômicas recessivas. Sessenta e cinco (53,3%) dos agrupamentos estavam localizados no Brasil. Conclusões. Os resultados da revisão reforçam a observação de que doenças raras e anomalias congênitas podem ocorrer de forma não aleatória no espaço, o que é discutido na perspectiva da complexa história de formação, organização social e estrutura genética da população sul-americana. O mapeamento de agrupamentos em genética médica populacional pode ser uma importante ferramenta de saúde pública, visto que esses locais concentram casos de doenças raras que frequentemente requerem atendimento multiprofissional especializado. Portanto, esses resultados podem apoiar importantes agendas de saúde pública relacionadas a doenças raras e anomalias congênitas, como a vigilância e a promoção da saúde.