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Introduction: Late infantile neuronal ceroid lipofuscinosis type 2 (CLN2), is a neurodegenerative autosomal recessive disease caused by TPP1 gene variants, with a spectrum of classic and atypical phenotypes. The aim of treatment is to slow functional decline as early as possible in an attempt to improve quality of life and survival. This study describes the clinical characteristics as well as the response to treatment with cerliponase alfa. Materials and methods: A retrospective study was conducted in five Latin-American countries, using clinical records from patients with CLN2. Clinical follow-up and treatment variables are described. A descriptive and bivariate statistical analysis was performed. Results: A total of 36 patients were observed (range of follow-up of 61-110 weeks post-treatment). At presentation, patients with the classic phenotype (n = 16) exhibited regression in language (90%), while seizures were the predominant symptom (87%) in patients with the atypical phenotype (n = 20). Median age of symptom onset and time to first specialized consultation was 3 (classical) and 7 (atypical) years, while the median time interval between onset of symptoms and treatment initiation was 4 years (classical) and 7.5 (atypical). The most frequent variant was c.827 A > T in 17/72 alleles, followed by c.622C > T in 6/72 alleles. All patients were treated with cerliponase alfa, and either remained functionally stable or had a loss of 1 point on the CLN2 scale, or up to 2 points on the Wells Cornel and Hamburg scales, when compared to pretreatment values. Discussion and conclusion: This study reports the largest number of patients with CLN2 currently on treatment with cerliponase alfa in the world. Data show a higher frequency of patients with atypical phenotypes and a high allelic proportion of intron variants in our region. There was evidence of long intervals until first specialized consultation, diagnosis, and enzyme replacement therapy. Follow-up after the initiation of cerliponase alfa showed slower progression or stabilization of the disease, associated with adequate clinical outcomes and stable functional scores. These improvements were consistent in both clinical phenotypes.
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La hiperamonemia constituye una emergencia médica. No existen publicaciones que hagan referencia a la disponibilidad de recursos, insumos y conocimientos necesarios para el manejo inicial de esta por parte del pediatra en nuestro país, pero, según la experiencia de los autores, los recursos necesarios no se encuentran disponibles los 365 días del año en una gran porción de nuestro territorio. Sobre la base de este estado de situación, de una revisión bibliográfica internacional sobre el tema y de la experiencia de los autores, se elaboraron una serie de recomendaciones para el manejo pediátrico inicial de esta emergencia, que tienen como objetivo poder reducir las deficiencias, permitir una sospecha clínica adecuada que lleve a un diagnóstico y tratamiento de emergencia oportunos, con utilización racional de recursos farmacológicos (algunos de ellos de alto costo), para reducir la morbimortalidad que asocia la patología.
Hyperammonemia is a medical emergency. There are no publications regarding the availability of resources, supplies, and knowledge necessary for the initial management of hyperammonemia by pediatricians in Argentina; however, according to the authors' experience, the necessary resources are not available all year round in a large portion of our territory. Based on such state of affairs, an international bibliographic review on this topic and the authors' experience, we developed a series of recommendations for the initial pediatric management of this emergency, with the objective of reducing deficiencies, allowing adequate clinical suspicion leading to a timely diagnosis and emergency management and a rational use of pharmacological resources (some of which are costly) to reduce the morbidity and mortality associated with hyperammonemia.
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Humanos , Lactente , Pré-Escolar , Criança , Hiperamonemia/diagnóstico , Hiperamonemia/terapia , Distúrbios Congênitos do Ciclo da Ureia/complicações , Distúrbios Congênitos do Ciclo da Ureia/diagnóstico , ArgentinaRESUMO
Hyperammonemia is a medical emergency. There are no publications regarding the availability of resources, supplies, and knowledge necessary for the initial management of hyperammonemia by pediatricians in Argentina; however, according to the authors' experience, the necessary resources are not available all year round in a large portion of our territory. Based on such state of affairs, an international bibliographic review on this topic and the authors' experience, we developed a series of ecommendations for the initial pediatric management of this emergency, with the objective of reducing deficiencies, allowing adequate clinical suspicion leading to a timely diagnosis and emergency management and a rational use of pharmacological resources (some of which are costly) to reduce the morbidity and mortality associated with hyperammonemia.
La hiperamonemia constituye una emergencia médica. No existen publicaciones que hagan referencia a la disponibilidad de recursos, insumos y conocimientos necesarios para el manejo inicial de esta por parte del pediatra en nuestro país, pero, según la experiencia de los autores, los recursos necesarios no se encuentran disponibles los 365 días del año en una gran porción de nuestro territorio. Sobre la base de este estado de situación, de una revisión bibliográfica internacional sobre el tema y de la experiencia de los autores, se elaboraron una serie de recomendaciones para el manejo pediátrico inicial de esta emergencia, que tienen como objetivo poder reducir las deficiencias, permitir una sospecha clínica adecuada que lleve a un diagnóstico y tratamiento de emergencia oportunos, con utilización racional de recursos farmacológicos (algunos de ellos de alto costo), para reducir la morbimortalidad que asocia la patología.
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Hiperamonemia , Distúrbios Congênitos do Ciclo da Ureia , Humanos , Criança , Hiperamonemia/diagnóstico , Hiperamonemia/terapia , Distúrbios Congênitos do Ciclo da Ureia/complicações , Distúrbios Congênitos do Ciclo da Ureia/diagnóstico , ArgentinaRESUMO
Neuronal ceroid lipofuscinoses (NCLs) comprise 13 hereditary neurodegenerative pathologies of very low frequency that affect individuals of all ages around the world. All NCLs share a set of symptoms that are similar to other diseases. The exhaustive collection of data from diverse sources (clinical, genetic, neurology, ophthalmology, etc.) would allow being able in the future to define this group with greater precision for a more efficient diagnostic and therapeutic approach. Despite the large amount of information worldwide, a detailed study of the characteristics of the NCLs in South America and the Caribbean region (SA&C) has not yet been done. Here, we aim to present and analyse the multidisciplinary evidence from all the SA&C with qualitative weighting and biostatistical evaluation of the casuistry. Seventy-one publications from seven countries were reviewed, and data from 261 individuals (including 44 individuals from the Cordoba cohort) were collected. Each NCL disease, as well as phenotypical and genetic data were described and discussed in the whole group. The CLN2, CLN6, and CLN3 disorders are the most frequent in the region. Eighty-seven percent of the individuals were 10 years old or less at the onset of symptoms. Seizures were the most common symptom, both at onset (51%) and throughout the disease course, followed by language (16%), motor (15%), and visual impairments (11%). Although symptoms were similar in all NCLs, some chronological differences could be observed. Sixty DNA variants were described, ranging from single nucleotide variants to large chromosomal deletions. The diagnostic odyssey was probably substantially decreased after medical education activities promoted by the pharmaceutical industry and parent organizations in some SA&C countries. There is a statistical deviation in the data probably due to the approval of the enzyme replacement therapy for CLN2 disease, which has led to a greater interest among the medical community for the early description of this pathology. As a general conclusion, it became clear in this work that the combined bibliographical/retrospective evaluation approach allowed a general overview of the multidisciplinary components and the epidemiological tendencies of NCLs in the SA&C region.
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Abstract Neuronal ceroid lipofuscinosis type 2 (CLN2) disease is a rare autosomal recessive neurodegenerative disorder caused by mutations in the CLN2/TPP1 gene, leading to a deficiency in tripeptidyl peptidase 1 activity. Enzyme replacement therapy with cerliponase alfa (recombinant human TPP1 [rhTPP1]; Brineura®) was approved in the United States and Europe for the treatment of CLN2 disease in 2017. We retrospectively report a cohort of 19 patients with CLN2 assisted in a specialized center in Argentina, including 8 newly diagnosed cases. Speech disorders and white matter changes/ventricular system enlargement were the most frequent clinical and imaging findings at CLN2 disease onset, respectively. Patients treated with cerliponase alfa presented a stable or improved course of the disease in this Latin American real world setting, as described in clinical trials.
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AIM: Neuronal ceroid lipofuscinosis type 2 (CLN2) disease is an autosomal recessive inherited neurodegenerative lysosomal storage disorder caused by deficient tripeptidyl peptidase 1 (TPP1) enzyme, leading to progressive deterioration of neurological functions commonly occurring in children aged 2-4 years and culminating in early death. Atypical cases associated with earlier or later symptom onset, or even protracted course, have already been reported. Such variable manifestations may constitute an additional challenge to early diagnosis and initiation of appropriate treatment. The present work aimed to analyse clinical data from a cohort of Latin American CLN2 patients with atypical phenotypes. METHODS: Experts in inborn errors of metabolism from Latin America selected patients from their centres who were deemed by the clinicians to have atypical forms of CLN2, according to the current literature on this topic and their practical experience. Clinical and genetic data from the medical records were retrospectively revised. All cases were presented and analysed by these experts at an Advisory Board Meeting in São Paulo, Brazil, in October 2018. RESULTS: Seizures, language abnormalities and behavioural disorders were found as the first manifestations, appearing at the median age of 6 years, an older age than classically described for the late infantile form. Three novel mutations were also identified. CONCLUSION: Our findings reinforce the inclusion of CLN2 in the differential diagnosis of children presenting with seizures, behavioural disorders and language abnormalities. Early diagnosis will allow early initiation of specific therapy.
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Lipofuscinoses Ceroides Neuronais , Idoso , Brasil , Criança , Pré-Escolar , Humanos , Lipofuscinoses Ceroides Neuronais/diagnóstico , Lipofuscinoses Ceroides Neuronais/genética , Fenótipo , Estudos Retrospectivos , Tripeptidil-Peptidase 1RESUMO
ABSTRACT Neuronal Ceroid Lipofuscinosis (NCL) refers to a group of inherited lysosomal storage disorders characterized by the intracellular accumulation of ceroid-lipofuscin compounds and neurodegeneration. Fourteen genes are currently recognized with disease-causing DNA variants: PPT1/CLN1, TPP1/CLN2, CLN3, DNAJC5/CLN4, CLN5, CLN6, MFSD8/CLN7, CLN8, CTSD/CN10, GRN/CLN11, ATP13A2/CLN12, CTSF/CLN13, KCTD7/CLN14, TBCK/CLN15. In the frame of the Cordoba cohort, we studied N=51 cases. The aim of this paper is the observational and retrospective analysis of the "atypical" phenotypes. PCR-Sanger sequencing and/or massive exome sequencing were used as a screening methodology. One CLN1 subject showed an atypical prolonged (P) phenotype with null PPT1 activity and a heterozygous compound genotype: E5 c.451C>T, p.Arg151*/g.6302T>G (I3 c.363-3T>G). Other 11 CLN2 individuals (except one girl) showed TPP1 activity decreased to around 10% of the minimum value of the reference interval in leukocytes and saliva. The DNA variants E7 c.827A>T, p.Asp276Val and I7 c.887-10A>G were the most prevalent. One CLN8 individual showed an atypical congenital phenotype with a heterozygous combination of DNA variants: E2 c.1A>G, p.?/E3 c.792C>G, p.Asn264Lys. Massive sequencing was installed as a screening methodology for the precision diagnosis of atypical CLN1, CLN2, and CLN8 phenotypes. A genetic/phenotypic local registry is under construction.
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Abstract Hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency is a disorder of purine metabolism responsible for Lesch-Nyhan Disease (LND) and its variants, HPRT-related hyperuricemia with neurologic dysfunction (HND) and HPRT-related hyperuricemia (HRH). The objective of this study was to characterize a cohort of Argentine patients with HPRT deficiency diagnosed in a single center. Results: Twenty nine patients were studied, including 12 LND, 15 HND and 2 HRH. The average onset age was 0.64 years for LND with motor delay as the main manifestation, 8.84 years for HND and 2.5 years for HRH; nephrological manifestations predominated as presenting features in these variants. The average diagnosis age was 3.58 years for LND, 17.21 years for HND and 2.5 years for HRH. Clinical heterogeneity was more evident in HND, even in members of the same family. All patients presented hyperuricemia and no detectable HPRT activity in erythrocyte lysate. The molecular study allowed to identify 9 different mutations in HPRT1 gene from 24 patients (11 independent pedigrees) and to establish genotype-phenotype correlation. In conclusion, this study describes the genotypic/phenotypic spectrum of HPRT deficiency in Argentine patients and highlights the need to increase awareness about the suspicion of these diseases, especially the LND variants with high clinical heterogeneity.
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Abstract Given the lack of standardized guidance for follow-up of patients with neuronal ceroid lipofucsinosis-2 disease in Latin-American countries and the heterogeneity of the region, an expert panel was created with the participation of 11 pediatric neurologists from Colombia, Argentina, Brazil and Chile. The aim of the expert panel was to describe a framework for standardized follow-up in patients with neuronal ceroid lipofucsinosis-2 disease, on or off therapy, that could benefit patients and treating physicians alike. Experts made recommendations in the following areas: seizures, abnormal movements and ataxia, sleep disorders and pain, cognitive function, visual function, hearing and speech, cardiac function, quality of life, and motor function. Recommendations include the most appropriate tools for use in the Latin-American context and health care systems, and provide feasible follow-up guidance, applicable in public and private healthcare facilities. They take into consideration the availability of clinical assessment resources, tools (scales, questionnaires, paraclinical tests) and access to these tools in Latin-American countries, as well as other regional and local needs defined by the participating experts.
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BACKGROUND: The incidence, prevalence, and molecular epidemiology of urea cycle disorders (UCDs) in Argentina remain underexplored. The present study is the first to thoroughly assess the clinical and molecular profiles of UCD patients examined at a single reference center in Argentina. RESULTS: Forty-nine UCD cases were collected. About half (26/49, 53%) manifested neonatally with classical presentation and had a high mortality (25/26, 96%). Ornithine transcarbamylase deficiency (OTCD) was the most common UCD (26 patients). Argininosuccinate synthetase deficiency (ASSD) was detected in 19 cases, while argininosuccinate lyase deficiency (ASLD) was diagnosed in 4 cases. Molecular genetic analysis revealed 8 private OTC mutations and two large deletion/duplication events in the OTC gene. Most mutations in the ASS1 and ASL genes were recurrent missense changes, and four alterations were novel. The clinical outcome of our UCD cohort was poor, with an overall mortality of 57% (28/49 cases), and a 28% (6/21) disability rate among the survivors. CONCLUSIONS: Most patients in our case series showed severe neonatal onset, with high morbidity/mortality. We detected in total 19 mutations, most of them recurrent and of high frequency worldwide. Noteworthy, we highlight the presence of a geographic cluster with high prevalence of a point mutation in the ASS1 gene. This study suggests that these disorders may be more frequent than commonly assumed, and stresses the need for increased awareness amongst health professionals and greater availability of diagnostic tools for accurate identification, early diagnosis, and timely treatment.