Clinical and molecular characterization of limb-girdle muscular dystrophy 2G/R7 in a large cohort of Brazilian patients.

Limb-girdle muscular dystrophy type 2G/R7 (LGMD2G/R7) is an ultra-rare condition initially identified within the Brazilian population. We aimed to expand clinical and genetic information about this disease, including its worldwide distribution. A multicenter historical cohort study was performed at 13 centers in Brazil in which data from index cases and their affected relatives from consecutive families with LGMD2G/R7 were reviewed from July 2017 to August 2023. Additionally, a systematic literature review was conducted to identify case reports and series of the disease worldwide. Forty-one LGMD2G/R7 cases were described in the Brazilian cohort, being all subjects homozygous for the c.157C>T/(p.Gln53*) variant in TCAP. Survival curves showed that the median disease duration before individuals required walking aids was 21 years. Notably, women exhibited a slower disease progression, requiring walking aids 13 years later than men. LGMD2G/R7 was frequently reported not only in Brazil but also in China and Bulgaria, with 119 cases identified globally, with possible founder effects in the Brazilian, Eastern European, and Asian populations. These findings are pivotal in raising awareness of LGMD2G/R7, understanding its progression, and identifying potential modifiers. This can significantly contribute to the development of future natural history studies and clinical trials for this disease.

Best practice guidelines on genetic diagnostics of facioscapulohumeral muscular dystrophy: Update of the 2012 guidelines.

The gold standard for facioscapulohumeral muscular dystrophy (FSHD) genetic diagnostic procedures was published in 2012. With the increasing complexity of the genetics of FSHD1 and 2, the increase of genetic testing centers, and the start of clinical trials for FSHD, it is crucial to provide an update on our knowledge of the genetic features of the FSHD loci and renew the international consensus on the molecular testing recommendations. To this end, members of the FSHD European Trial Network summarized the evidence presented during the 2022 ENMC meeting on Genetic diagnosis, clinical outcome measures, and biomarkers. The working group additionally invited genetic and clinical experts from the USA, India, Japan, Australia, South-Africa, and Brazil to provide a global perspective. Six virtual meetings were organized to reach consensus on the minimal requirements for genetic confirmation of FSHD1 and FSHD2. Here, we present the clinical and genetic features of FSHD, specific features of FSHD1 and FSHD2, pros and cons of established and new technologies (Southern blot in combination with either linear or pulsed-field gel electrophoresis, molecular combing, optical genome mapping, FSHD2 methylation analysis and FSHD2 genotyping), the possibilities and challenges of prenatal testing, including pre-implantation genetic testing, and the minimal requirements and recommendations for genetic confirmation of FSHD1 and FSHD2. This consensus is expected to contribute to current clinical management and trial-readiness for FSHD.

Whole-Exome Sequencing Study of Fibroblasts Derived From Patients With Cerebellar Ataxia Referred to Investigate CoQ10 Deficiency.

Background and Objectives: Coenzyme Q10 (CoQ10)-deficient cerebellar ataxia can be due to pathogenic variants in genes encoding for CoQ10 biosynthetic proteins or associated with defects in protein unrelated to its biosynthesis. Diagnosis is crucial because patients may respond favorably to CoQ10 supplementation. The aim of this study was to identify through whole-exome sequencing (WES) the pathogenic variants, and assess CoQ10 levels, in fibroblasts from patients with undiagnosed cerebellar ataxia referred to investigate CoQ10 deficiency. Methods: WES was performed on genomic DNA extracted from 16 patients. Sequencing data were filtered using a virtual panel of genes associated with CoQ10 deficiency and/or cerebellar ataxia. CoQ10 levels were measured by high-performance liquid chromatography in 14 patient-derived fibroblasts. Results: A definite genetic etiology was identified in 8 samples of 16 (diagnostic yield = 50%). The identified genetic causes were pathogenic variants of the genes COQ8A (ADCK3) (n = 3 samples), ATP1A3 (n = 2), PLA2G6 (n = 1), SPG7 (n = 1), and MFSD8 (n = 1). Five novel mutations were found (COQ8A n = 3, PLA2G6 n = 1, and MFSD8 n = 1). CoQ10 levels were significantly decreased in 3/14 fibroblast samples (21.4%), 1 carrying compound heterozygous COQ8A pathogenic variants, 1 harboring a homozygous pathogenic SPG7 variant, and 1 with an unknown molecular defect. Discussion: This work confirms the importance of COQ8A gene mutations as a frequent genetic cause of cerebellar ataxia and CoQ10 deficiency and suggests SPG7 mutations as a novel cause of secondary CoQ10 deficiency.

Clinicogenetic lessons from 370 patients with autosomal recessive limb-girdle muscular dystrophy.

Limb-girdle muscular dystrophies (LGMD) are a group of genetically heterogeneous disorders characterized by predominantly proximal muscle weakness. We aimed to characterize epidemiological, clinical and molecular data of patients with autosomal recessive LGMD2/LGMD-R in Brazil. A multicenter historical cohort study was performed at 13 centers, in which index cases and their affected relatives' data from consecutive families with genetic or pathological diagnosis of LGMD2/LGMD-R were reviewed from July 2017 to August 2018. Survival curves to major handicap for LGMD2A/LGMD-R1-calpain3-related, LGMD2B/LGMD-R2-dysferlin-related and sarcoglycanopathies were built and progressions according to sex and genotype were estimated. In 370 patients (305 families) with LGMD2/LGMD-R, most frequent subtypes were LGMD2A/LGMD-R1-calpain3-related and LGMD2B/LGMD-R2-dysferlin-related, each representing around 30% of families. Sarcoglycanopathies were the most frequent childhood-onset subtype, representing 21% of families. Five percent of families had LGMD2G/LGMD-R7-telethonin-related, an ultra-rare subtype worldwide. Females with LGMD2B/LGMD-R2-dysferlin-related had less severe progression to handicap than males and LGMD2A/LGMD-R1-calpain3-related patients with truncating variants had earlier disease onset and more severe progression to handicap than patients without truncating variants. We have provided paramount epidemiological data of LGMD2/LGMD-R in Brazil that might help on differential diagnosis, better patient care and guiding future collaborative clinical trials and natural history studies in the field.

Idiopathic hyperCKemia and malignant hyperthermia susceptibility.

PURPOSE: HyperCKemia is a persistent rise in serum creatine kinase (CK) levels of at least 1.5 times the normal value, as evidenced by a minimum of two measurements at 30-day intervals. One of the neuromuscular diseases associated with hyperCKemia is malignant hyperthermia (MH). This study investigated the susceptibility to MH in patients with hyperCKemia via in vitro contracture testing (IVCT) and a search of mutations in the RYR1 gene. METHODS: Patients in an MH centre were followed from 1997-2012, and their epidemiologic, clinical, and laboratory data were analyzed, including IVCT, muscle histochemical analysis, and next-generation sequencing molecular analysis. RESULTS: There were nine patients (eight male) in our study with a mean (SD) age of 33 (12) yr. Four patients were Caucasian and five were African Brazilian. Most complained about myalgia or cramps, but all had a normal neurological examination. They persistently presented with hyperCKemia from three months to ten years, with a mean (SD) CK value of 788 (507) IU·L-1 ranging from 210-1,667 IU·L-1. These values corresponded to a 1.5- to nine-fold increase in the normal value (mean increase, 3.7-fold). Six patients were MH susceptible (MHS) after a positive IVCT. Histopathological muscular analysis disclosed unspecified changes in four of the MHS patients. Mitochondrial proliferation was observed in the other two MHS patients and in three MH negative patients. No pathogenic mutations were identified in the RYR1 gene in the five patients evaluated. CONCLUSION: When investigating patients with idiopathic hyperCKemia, susceptibility to MH should be taken into account, and guidance should be offered to prevent anesthetic complications in the family.

Reliability and validity analyses of the North Star Ambulatory Assessment in Brazilian Portuguese.

The North Star Ambulatory Assessment measures motor performance in ambulatory boys with Duchenne muscular dystrophy, a hereditary and degenerative muscle disorder. To use the North Star Ambulatory Assessment in Brazilian boys, we performed the cross-cultural adaptation to the Portuguese language spoken in Brazil and evaluated the reliability and validity of the instrument. Cross-cultural adaptation included: independent translations, synthesis, committee review, pre-testing in 12 boys, back-translation and comparison with the original instrument. Thirty-five boys with Duchenne muscular dystrophy and 38 healthy age-matched controls were recruited for further analyses. Reliability was assessed by internal consistency and reproducibility. Validity studies included face, content, construct and known-groups analyses. Cross-cultural adaptation resulted in an adequate instrument. Reliability studies demonstrated high internal consistency (Cronbach's alpha = 0.935) and adequate intra and inter-rater reproducibility (intraclass correlation coefficient = 0.988 and 0.962). Validation analyses indicated satisfactory content, face and convergent construct validities, with positive correlations with the Motor Function Measure total score (r = 0.863) and the 6-minute walk test (r = 0.433). The known group validity was demonstrated by higher scores in younger boys with Duchenne muscular dystrophy (p = 0.005). North Star Ambulatory Assessment in Brazilian Portuguese is a reliable and valid instrument to measure functional capacity in boys with Duchenne muscular dystrophy.

Guidelines for the diagnosis, treatment and clinical monitoring of patients with juvenile and adult Pompe disease / Diretriz para o diagnóstico, tratamento e acompanhamento clínico de pacientes com doença de Pompe juvenil e do adulto

ABSTRACT Pompe disease (PD) is a potentially lethal illness involving irreversible muscle damage resulting from glycogen storage in muscle fiber and activation of autophagic pathways. A promising therapeutic perspective for PD is enzyme replacement therapy (ERT) with the human recombinant enzyme acid alpha-glucosidase (Myozyme®). The need to organize a diagnostic flowchart, systematize clinical follow-up, and establish new therapeutic recommendations has become vital, as ERT ensures greater patient longevity. A task force of experienced clinicians outlined a protocol for diagnosis, monitoring, treatment, genetic counseling, and rehabilitation for PD patients. The study was conducted under the coordination of REBREPOM, the Brazilian Network for Studies of PD. The meeting of these experts took place in October 2013, at L’Hotel Port Bay in São Paulo, Brazil. In August 2014, the text was reassessed and updated. Given the rarity of PD and limited high-impact publications, experts submitted their views.

RESUMO A doença de Pompe (DP) é uma doença grave, potencialmente letal, devida ao depósito de glicogênio na fibra muscular e ativação de vias autofágicas. Tratamento promissor para a DP é a reposição enzimática com a enzima recombinante humana alfa-glicosidase ácida (rhAGA -Myozyme®). A necessidade de organizar uma propedêutica diagnóstica, sistematizar o seguimento clínico e sedimentar as novas recomendações terapêuticas tornaram-se vitais à medida que o tratamento permite uma maior longevidade aos pacientes. Uma força-tarefa de clínicos experientes no manejo da DP foi constituída para elaborar um protocolo para o diagnóstico, acompanhamento clínico, tratamento, aconselhamento genético, entre outras considerações voltadas ao paciente adulto. O estudo foi realizado sob a coordenação da Rede Brasileira de Estudos da Doença de Pompe (REBREPOM). Diante da raridade da DP e escassez de trabalhos de alto impacto de evidência científica, os especialistas emitiram suas opiniões.

Guidelines for the diagnosis, treatment and clinical monitoring of patients with juvenile and adult Pompe disease.

Pompe disease (PD) is a potentially lethal illness involving irreversible muscle damage resulting from glycogen storage in muscle fiber and activation of autophagic pathways. A promising therapeutic perspective for PD is enzyme replacement therapy (ERT) with the human recombinant enzyme acid alpha-glucosidase (Myozyme®). The need to organize a diagnostic flowchart, systematize clinical follow-up, and establish new therapeutic recommendations has become vital, as ERT ensures greater patient longevity. A task force of experienced clinicians outlined a protocol for diagnosis, monitoring, treatment, genetic counseling, and rehabilitation for PD patients. The study was conducted under the coordination of REBREPOM, the Brazilian Network for Studies of PD. The meeting of these experts took place in October 2013, at L'Hotel Port Bay in São Paulo, Brazil. In August 2014, the text was reassessed and updated. Given the rarity of PD and limited high-impact publications, experts submitted their views.

Erros inatos do metabolismo confirmados no Hospital das Clínicas de Ribeirão Preto-SP no período de 2000 a 2008 / Inborn errors of metabolism in the Hospital of Clinics of Ribeirão Preto - SP from 2000 to 2008

Os Erros Inatos do Metabolismo (EIM) vêm sendo cada vez mais identificados nos últimos anos. A preocupação com o diagnóstico precoce decorre do foco na prevenção de deficiências, especialmente a mental. Este estudo descritivo teve por objetivo verificar diagnósticos confirmados e modalidades de tratamento utilizadas de janeiro de 2000 a dezembro de 2008. Método: foi realizada busca ativa de casos confirmados nos serviços que atendem esse tipo doença: neurologia (neuropediatria e doençasneuromusculares), pediatria (serviço de gastrologia e hepatologia) e genética clínica, além de levantamento no Serviço de Arquivo Médico do HCFMRP-USP. Foram confirmados 165 pacientes com EIM, com idades de um dia a 22 anos (mediana de um ano); 50 casos foram defeitos na síntese ou catabolismo de moléculas complexas, 65 no metabolismo intermediário, e 50 na produção ou utilização de energia. O tratamento foi instituído para 12 dos 50 pacientes do grupo I sendo reposição enzimática em 11 e transplante de medula óssea em um; todos do grupo II e III receberam orientação nutricional; 60 do grupo II receberam fórmula dietética industrializada; dos 50 do grupo III, 43 com mitocondriopatias receberam L-carnitina e coenzimas e aqueles com glicogenose, orientação sobre aporte de carbohidratos. A formação de novos recursos humanos, integração com a Rede EIM Brasil e linhas de pesquisa na área são prioridades para melhorar a acuidade na detecção e tratamento de erros inatos do metabolismo.

Inborn Errors of Metabolism have been increasingly identified in recent years. The early diagnosis focuses on prevention of disabilities, especially mental retardation. This descriptive study aims to verify confirmed diagnosis and treatment modalities in HCFMRP-USP cases from January of 2000 to December of 2008. A total of 165 patients with ages ranging from one day to 22 years (median one year) were detected. Fifty patients had synthesis or catabolism of complex molecules (group I), 65 intermediary metabolism (group II), and 50 had production or use of energy (group III) defects. Among the patients of group I, 11 had enzyme replacement therapy, and one bone marrow transplantation; for group II and III, inaddition to daily nutritional guidance for all of the patients, 60 from group II received industrialized diets; from group III, 43 with mitochondrial diseases received L-carnitine and coenzymes, and those with glycogenosis were focused mainly on the intake of carbohydrates. New human resources, integration with the Network EIM Brazil and lines of research in the area are priorities for improving the accuracy in the detection and treatment of inborn errors of metabolism.