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.

Preservation of shortening velocity and power output in single muscle fibres from patients with idiopathic inflammatory myopathies.

Idiopathic inflammatory myopathies (IIMs) are autoimmune disorders of skeletal muscle causing weakness and disability. Utilizing single fibre contractility studies, we have previously shown that contractility is affected in muscle fibres from individuals with IIMs. For the current study, we hypothesized that a compensatory increase in shortening velocity occurs in muscle fibres from individuals with IIMs in an effort to maintain power output. We performed in vitro single fibre contractility studies to assess force-velocity relationships and maximum shortening velocity (Vmax) of muscle fibres from individuals with IIMs (25 type I and 58 type IIA) and healthy controls (66 type I and 27 type IIA) and calculated maximum power output (Wmax) for each fibre. We found significantly higher Vmax (mean ± SEM) of fibres from individuals with IIMs, for both type I (1.40 ± 0.31 fibre lengths/s, n = vs. 0.63 ± 0.13 fibre lengths/s; p = 0.0019) and type IIA fibres (2.00 ± 0.17 fibre lengths/s vs 0.77 ± 0.10 fibre lengths/s; p < 0.0001). Furthermore, Wmax (mean ± SEM) was maintained compared to fibres from healthy controls, again for both type I and type IIA fibres (4.10 ± 1.00 kN/m2·fibre lengths/s vs. 2.00 ± 0.16 kN/m2·fibre lengths/s; p = ns and 9.00 ± 0.64 kN/m2·fibre lengths/s vs. 6.00 ± 0.67 kN/m2·fibre lengths/s; p = ns respectively). In addition, type I muscle fibres from individuals with IIMs was able to develop maximum power output at lower relative force. The findings of this study suggest that compensatory responses to maintain power output, including increased maximum shortening velocity and improved efficiency, may occur in muscle of individuals with IIMs. The mechanism underlying this response is unclear, and different hypotheses are discussed.

An exploratory study of contractile force production in muscle fibers from patients with inflammatory myopathies.

INTRODUCTION: The mechanism by which weakness develops in idiopathic inflammatory myopathies (IIMs) is still unclear. In this study we investigated the maximum force of single muscle fibers from patients with IIMs. METHODS: Permeabilized single muscle fibers from patients with IIMs and healthy controls were subjected to contractility measurements. Maximum force and specific force production (maximum force normalized to fiber size) and fiber type were determined for each isolated fiber. RESULTS: A total of 178 fibers were studied from five patients with IIMs and 95 fibers from four controls. Specific force production was significantly lower in the IIM group for all fiber types. DISCUSSION: The findings from this exploratory study suggest that weakness in IIMs may, in part, be caused by dysfunction of the contractile apparatus. These findings provide a basis for further studies into the mechanisms underlying weakness in IIMs.

Clinical features and prognosis of amyotrophic lateral sclerosis in Africa: the TROPALS study.

OBJECTIVE: We describe and compare the sociodemographic and clinical features, treatments, and prognoses and survival times of patients with amyotrophic lateral sclerosis (ALS) in Africa. METHODOLOGY: We conducted a multicentre, hospital-based cohort study in Africa. Patients with ALS diagnosed in the neurology departments of participating hospitals from 2005 to 2017 were included. Subgroup analysis was performed by subcontinent. Survival analyses were conducted using the Cox proportional hazards model. RESULTS: Nine centres from eight African countries participated. A total of 185 patients with ALS were included: 114 from Northern Africa, 41 from Western Africa and 30 from Southern Africa. A male predominance (male to female ratio 2.9) was evident. The median age at onset was 53.0 years (IQR 44.5-64.0 years). The onset was bulbar in 22.7%. Only 47 patients (26.3%) received riluzole, mainly in Northern and Western Africa. The median survival from the time of diagnosis was 14.0 months (95% CI 10.7 to 17.2 months). The median survival was longer in Northern Africa (19.0 months, 95% CI 10.8 to 27.2 months) than in Western (4.0 months, 95% CI 0.8 to 7.1 months) and Southern (11.0 months, 95% CI 5.6 to 16.4 months) Africa (Breslow test, p<0.0001). Both subcontinental location and riluzole treatment independently affected survival. CONCLUSION: More African patients with ALS were male and younger and exhibited a lower proportion of bulbar onset compared with patients with ALS from Western nations. Survival was consistent with that in Western registers but far shorter than what would be expected for young patients with ALS. The research improves our understanding of the disease in Africa.

Baboon (Papio ursinus) single fibre contractile properties are similar to that of trained humans.

This study investigated the contractile properties of single skeletal muscle fibres from the Vastus lateralis (VL) of two male adult chachma baboons (Papio ursinus) and compared it to that from five male human cyclists. Species comparisons are observational and statistical analyses were not performed due to the low sample size. The histological analyses revealed that the baboon muscles contained more type II fibres than their human counterparts. Cross-sectional areas of type I and type II fibres from human VL were similar in size, whereas baboon type I and type II fibres appeared smaller and larger compared to humans, respectively. On average, type II fibres from baboons and type IIAX fibres from humans produced the highest specific force (88 ± 41 and 155 ± 4 kN/m2, respectively), compared to 57 ± 27 and 68 ± 5 kN/m2 for baboon and human type I fibres. Maximum shortening velocity appeared highest in human type IIAX fibres, but fairly similar between human and baboon type I and II fibres. Baboon and human type I (2.2 ± 0.4 vs. 1.5 ± 0.5 kN/m2 Fl/s) and type II (6.0 ± 2.8 vs. 7.7 ± 1.0 kN/m2 Fl/s) fibres appeared similar in maximum power output. From these observations, it seems that baboon and human muscle fibre contractile properties appear similar to one another, and that fibre type composition itself may play a determining role in muscle strength between these two species.

Using Eulerian video magnification to enhance detection of fasciculations in people with amyotrophic lateral sclerosis.

INTRODUCTION: This study seeks to determine whether the use of Eulerian video magnification (EVM) increases the detection of muscle fasciculations in people with amyotrophic lateral sclerosis (PALS) compared with direct clinical observation (DCO). METHODS: Thirty-second-long video recordings were taken of 9 body regions of 7 PALS and 7 controls, and fasciculations were counted by DCO during the same 30-s period. The video recordings were then motion magnified and reviewed by 2 independent assessors. RESULTS: In PALS, median fasciculation count per body region was 1 by DCO (range 0-10) and 3 in the EVM recordings (range 0-15; P < 0.0001). EVM revealed more fasciculations than DCO in 61% of recordings. In controls, median fasciculation count was 0 for both DCO and EVM. DISCUSSION: Compared with DCO, EVM significantly increased the detection of fasciculations in body regions of PALS. When it is used to supplement clinical examination, EVM has the potential to facilitate the diagnosis of ALS. Muscle Nerve 56: 1063-1067, 2017.

Muscle fiber type proportion and size is not altered in mcardle disease.

INTRODUCTION: McArdle disease is a metabolic myopathy that presents with exercise intolerance and episodic rhabdomyolysis. Excessive muscle recruitment has also been shown to be present during strenuous exercise, suggesting decreased power output. These findings could potentially be explained by either impaired contractility, decreased fiber size, or altered fiber type proportion. However, there is a paucity of data on the morphological features seen on muscle histology. METHODS: We examined muscle biopsies of patients with McArdle disease from a Spanish cohort and compared the findings with healthy controls. RESULTS: We found no significant difference in the fiber type proportion or mean fiber size between McArdle patients and controls in the biceps brachii or vastus lateralis muscles. CONCLUSIONS: No alterations in muscle fiber type proportion or size were found on muscle histology of patients with McArdle disease. Future research should focus on assessment of muscle fiber contractility to investigate the functional impairment. Muscle Nerve 55: 916-918, 2017.

Mitochondrial impairment observed in fibroblasts from South African Parkinson's disease patients with parkin mutations.

Parkinson's disease (PD), defined as a neurodegenerative disorder, is characterized by the loss of dopaminergic neurons in the substantia nigra in the midbrain. Loss-of-function mutations in the parkin gene are a major cause of autosomal recessive, early-onset PD. Parkin has been implicated in the maintenance of healthy mitochondria, although previous studies show conflicting findings regarding mitochondrial abnormalities in fibroblasts from patients harboring parkin-null mutations. The aim of the present study was to determine whether South African PD patients with parkin mutations exhibit evidence for mitochondrial dysfunction. Fibroblasts were cultured from skin biopsies obtained from three patients with homozygous parkin-null mutations, two heterozygous mutation carriers and two wild-type controls. Muscle biopsies were obtained from two of the patients. The muscle fibers showed subtle abnormalities such as slightly swollen mitochondria in focal areas of the fibers and some folding of the sarcolemma. Although no differences in the degree of mitochondrial network branching were found in the fibroblasts, ultrastructural abnormalities were observed including the presence of electron-dense vacuoles. Moreover, decreased ATP levels which are consistent with mitochondrial dysfunction were observed in the patients' fibroblasts compared to controls. Remarkably, these defects did not manifest in one patient, which may be due to possible compensatory mechanisms. These results suggest that parkin-null patients exhibit features of mitochondrial dysfunction. Involvement of mitochondria as a key role player in PD pathogenesis will have important implications for the design of new and more effective therapies.

Clinical, biochemical, and genetic spectrum of MADD in a South African cohort: an ICGNMD study.

BACKGROUND: Multiple acyl-CoA dehydrogenase deficiency (MADD) is an autosomal recessive disorder resulting from pathogenic variants in three distinct genes, with most of the variants occurring in the electron transfer flavoprotein-ubiquinone oxidoreductase gene (ETFDH). Recent evidence of potential founder variants for MADD in the South African (SA) population, initiated this extensive investigation. As part of the International Centre for Genomic Medicine in Neuromuscular Diseases study, we recruited a cohort of patients diagnosed with MADD from academic medical centres across SA over a three-year period. The aim was to extensively profile the clinical, biochemical, and genomic characteristics of MADD in this understudied population. METHODS: Clinical evaluations and whole exome sequencing were conducted on each patient. Metabolic profiling was performed before and after treatment, where possible. The recessive inheritance and phase of the variants were established via segregation analyses using Sanger sequencing. Lastly, the haplotype and allele frequencies were determined for the two main variants in the four largest SA populations. RESULTS: Twelve unrelated families (ten of White SA and two of mixed ethnicity) with clinically heterogeneous presentations in 14 affected individuals were observed, and five pathogenic ETFDH variants were identified. Based on disease severity and treatment response, three distinct groups emerged. The most severe and fatal presentations were associated with the homozygous c.[1067G > A];c.[1067G > A] and compound heterozygous c.[976G > C];c.[1067G > A] genotypes, causing MADD types I and I/II, respectively. These, along with three less severe compound heterozygous genotypes (c.[1067G > A];c.[1448C > T], c.[740G > T];c.[1448C > T], and c.[287dupA*];c.[1448C > T]), resulting in MADD types II/III, presented before the age of five years, depending on the time and maintenance of intervention. By contrast, the homozygous c.[1448C > T];c.[1448C > T] genotype, which causes MADD type III, presented later in life. Except for the type I, I/II and II cases, urinary metabolic markers for MADD improved/normalised following treatment with riboflavin and L-carnitine. Furthermore, genetic analyses of the most frequent variants (c.[1067G > A] and c.[1448C > T]) revealed a shared haplotype in the region of ETFDH, with SA population-specific allele frequencies of < 0.00067-0.00084%. CONCLUSIONS: This study reveals the first extensive genotype-phenotype profile of a MADD patient cohort from the diverse and understudied SA population. The pathogenic variants and associated variable phenotypes were characterised, which will enable early screening, genetic counselling, and patient-specific treatment of MADD in this population.

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and Human Immunodeficiency virus infection: dilemmas in diagnosis and management: a case series.

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a recently described autoimmune inflammatory disorder of the central nervous system (CNS). There is limited data on the association between Human Immunodeficiency virus (HIV) infection and MOGAD. We report three patients with HIV infection and myelin oligodendrocyte glycoprotein (MOG) antibodies in the setting of other central nervous system infections. CASE DESCRIPTIONS: The first patient, a 44-year-old black African man, presented with acute disseminated encephalomyelitis (ADEM) with positive serum MOG antibodies. He made a significant recovery with corticosteroids but had a quick relapse and died from sepsis. The second patient, an 18-year-old black woman, presented with paraplegia and imaging revealed a longitudinally extensive transverse myelitis and had positive serum MOG antibodies. She remained paraplegic after methylprednisone and plasmapheresis treatments. Her rehabilitation was complicated by development of pulmonary embolism and tuberculosis. The third patient, a 43-year-old mixed-race woman, presented with bilateral painless visual loss. Her investigations were notable for positive MOG antibodies, positive Varicella Zoster Virus on cerebral spinal fluid (CSF) and hyperintense optic nerves on magnetic resonance imaging (MRI). Her vision did not improve with immunosuppression and eventually died from sepsis. CONCLUSION: Our cases illustrate the diagnostic and management challenges of MOGAD in the setting of advanced HIV infection, where the risk of CNS opportunistic infections is high even without the use of immunosuppression. The atypical clinical progression and the dilemmas in the diagnosis and treatment of these cases highlight gaps in the current knowledge of MOGAD among people with HIV that need further exploration.

Modification of the ALSFRS-R for Utilization in Individuals Not Using Noninvasive Ventilation.

BACKGROUND: The Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) is widely employed in assessing functional decline in individuals with amyotrophic lateral sclerosis (ALS). A limitation of the scale is that item 12 does not directly evaluate worsening respiratory failure in ALS but rather the management thereof as a surrogate marker. We propose an alternative scale to assess respiratory function in ALS individuals who do not use noninvasive ventilation (NIV). METHODS: 85 participants were included in the study. ALSFRS-R scores were calculated and FVC measured at each clinic visit. Additional questions were asked regarding the presence of nocturnal hypoventilation symptoms, including (1) early-morning headaches, (2) excessive daytime somnolence, (3) poor concentration, and (4) decrease in appetite. A nocturnal hypoventilation item was developed using these questions in participants not using NIV. Internal consistency and validity were calculated using the nocturnal hypoventilation item as substitute for the existing item 12. The ALSFRS-R was modified by adding the alternative item 12 and named ALSFRS-Revised Modified (ALSFRS-RM). RESULTS: The ALSFRS-RM has a strong internal consistency and validity, which was calculated using Cronbach alpha and factor analysis. A Spearman correlation of 0.34 was calculated between the measured FVC and the nocturnal hypoventilation item score. In addition, a nocturnal hypoventilation item score of ≤ 3 corresponds to an FVC of ≤ 65%, with the upper 95% CI < 80%. CONCLUSIONS: Our results suggest that the addition of an alternative item 12 to the existing ALSFRS-R may be a viable option for use in individuals not receiving ventilatory support. The new nocturnal hypoventilation item may also be a reliable indicator of respiratory decline that may remove the need for FVC measurement prior to introducing NIV.

Clinical management and disease-modifying treatment for amyotrophic lateral sclerosis in African hospital centers: the TROPALS study.

Objective: To assess the availability of health workers and medications for clinical management of amyotrophic lateral sclerosis (ALS) in African hospital centers. Availability and affordability analyses of disease-modifying treatments were performed. Methods: A multicenter observational study involving African hospitals was conducted. A standard questionnaire was developed based on the European Federation of the Neurological Societies (EFNS) guidelines. We collected data on multidisciplinary care and availability of medicines. The availability and affordability were evaluated according to the WHO guidelines. Results: Nine hospital centers from eight African countries participated. We observed a low degree of implementation of multidisciplinary care in ALS management. Riluzole was only available in centers from South Africa, Senegal, Tunisia, and Togo. This treatment was unaffordable and the adjusted price was highly variable among countries. The cost of riluzole was partly or fully covered by patients, which implies a substantial economic burden. Conclusion: Our findings strengthen the need to promote multidisciplinary care in the clinical management of ALS in Africa. Disease-modifying medication should be both available and affordable. Local and international collaboration is needed to improve ALS health care access in Africa.

A comparative study of South African and Portuguese amyotrophic lateral sclerosis cohorts.

OBJECTIVE: Data on the epidemiological and clinical aspects of ALS originate from a few world regions, and very little is known about ALS in low and middle-income countries, in particular Sub-Saharan Africa. This brief report attempts to provide preliminary perspectives on the clinical features and management of ALS in Sub-Saharan Africa by comparing two cohorts from South Africa (SA) and Portugal. METHODS: The study was performed at ALS clinics at Tygerberg Hospital, Cape Town, South Africa, and Centro Hospitalar Universitário Lisboa-Norte, Portugal. We included all patients diagnosed over a four-year period, and collected demographic and clinical data at diagnosis, longitudinal data on disease progression and management over 12 months, and mortality rates at 12 and 24 months. RESULTS: SA patients were younger and had a higher rate of spinal-onset disease than their Portuguese counterparts. During the 12-month follow-up, NIV was introduced in half of Portuguese patients, but only a quarter of SA patients. Parenteral nutrition was introduced in less than 10% of patients in both groups. No SA patients used riluzole, while 100% of Portuguese patients did. Mortality rates were significantly higher in the SA cohort at both 12 months (35% vs 16%; p < .0001) and 24 months (63% vs 39%; p < .0001). CONCLUSIONS: Although SA patients were younger and more likely to have spinal-onset disease, mortality was higher in this cohort. There was a significant difference in utilisation of NIV and riluzole between the two cohorts, both of which may influence survival.

Immune cell membrane fatty acids and inflammatory marker, C-reactive protein, in patients with multiple sclerosis.

Measurement of fatty acids in biological fluids and cell membranes including leucocytes from multiple sclerosis patients is inconsistent. The objective of the present study was to investigate the fatty acid composition within the different membrane phospholipid fractions in peripheral blood mononuclear cells in multiple sclerosis patients, and correlate with severity of neurological outcome as measured by the Kurtzke Expanded Disability Status Scale and Functional System Scores. The fatty acid composition of phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, sphingomyelin and phosphatidylinositol phospholipids in the peripheral blood mononuclear cells of twenty-six multiple sclerosis and twenty-five control subjects were measured by GC, and C-reactive protein was measured in all subjects. The elongation product of 20 : 4n-6, 22 : 4n-6, was significantly decreased in membrane phosphatidylethanolamine and phosphatidylserine in multiple sclerosis patients (P = 0.01 and P = 0.03 respectively), and correlated inversely with severity of disease and C-reactive protein. Also an inverse correlation was observed between the C-reactive protein and membrane phosphatidylcholine and phosphatidylserine 20 : 4n-6. Cultural and ethnic differences, as well as dietary variability, especially in a diseased state have been implicated in the differences observed in the fatty acid composition in peripheral blood mononuclear cell membranes of patients with multiple sclerosis. The present results suggest that the disease state may in part explain the reported inconsistencies in fatty acid levels in multiple sclerosis patients.

C9orf72 repeat expansions in South Africans with amyotrophic lateral sclerosis.

The hexanucleotide repeat expansion in the C9orf72 gene is the most common genetic variant found in individuals with sporadic amyotrophic lateral sclerosis (ALS), occurring at a frequency of between 7 and 11% in cohorts of European ancestry. While limited data suggest that C9-expansions (>30 repeats) are less frequent in African-Americans with ALS, there is no data on the frequency of C9-expansions among ALS subjects residing in Africa. We therefore investigated the frequency of this expansion mutation (using repeat-primed PCR) in a cohort of 143 South Africans (SA) with ALS. The cohort included different genetic ancestry subgroups who self-identified as black African (n = 24), Cape mixed-African (M/A) (n = 65), white European ancestry (n = 51), and Indian ancestry (n = 3). Three M/A individuals had a family history of ALS (2%) and all had normal C9orf72 alleles. Of the 140 individuals with sporadic ALS who were successfully genotyped, 10 (7%) carried pathogenic C9-expansions; four white and six M/A ancestry individuals, respectively. Our results highlight the importance of including Africans in genetic studies aimed at unravelling the genomic architecture in ALS and suggest pathogenetic mechanisms other than the C9orf72 expansion in black Africans with ALS.