Additive effects of a family history of schizophrenia spectrum disorders and an environmental risk score for the outcome of patients with non-affective first-episode psychosis.

BACKGROUND: First-episode psychotic disorders comprise a heterogeneous phenotype with a complex etiology involving numerous common small-effect genetic variations and a wide range of environmental exposures. We examined whether a family of schizophrenia spectrum disorder (FH-Sz) interacts with an environmental risk score (ERS-Sz) regarding the outcome of patients with non-affective first episode psychosis (NAFEP). METHODS: We included 288 patients with NAFEP who were evaluated after discharge from an intensive 2-year program. We evaluated three outcome measures: symptomatic remission, psychosocial functioning, and personal recovery. We analyzed the main and joint associations of a FH-Sz and the ERS-Sz on the outcomes by using the relative excess risk due to interaction (RERI) approach. RESULTS: A FH-Sz showed a significant association with poor symptomatic remission and psychosocial functioning outcomes, although there was no significant interaction between a FH-Sz and the ERS-Sz on these outcomes. The ERS-Sz did not show a significant association with poor symptomatic remission and psychosocial functioning outcomes, even though the magnitude of the interaction between ERS-Sz and FH-Sz with the later outcome was moderate (RERI = 6.89, 95% confidence interval -16.03 to 29.81). There was no association between a FH-Sz and the ERS-Sz and personal recovery. CONCLUSIONS: Our results provide further empirical support regarding the contribution of FH-Sz to poor symptomatic remission and poor psychosocial functioning outcomes in patients with NAFEP.

The CAPN3 p.Lys 254del variant is not always associated with dominant CAPN3-related muscular dystrophy.

INTRODUCTION/AIMS: Limb-girdle muscular dystrophy R1 (LGMDR1) calpain 3-related usually presents as a recessively transmitted weakness of proximal limb-girdle muscles due to pathogenic variants in the CAPN3 gene. Pathogenic variants in this gene have also been found in patients with an autosomal dominantly inherited transmission pattern (LGMDD4). The mechanism underlying this difference in transmission patterns has not yet been elucidated. Camptocormia, progressive limb weakness, myalgia, back pain, and increased CK levels are common clinical features associated with dominant forms. The p.Lys254del pathogenic variant was associated with camptocormia in two LGMDD4 families. This study aimed to present carriers found in recessively transmitted LGMDR1 families bearing the p.Lys254del variant that do not show muscle weakness. METHODS: DNA sequencing was performed on exon 5 of CAPN3 in family members to establish the carrier status of the pathogenic variant. They were evaluated clinically and MRI was performed when available. RESULTS: Two families presented with the p.Lys254del pathogenic variant in a homozygous or compound heterozygous state. Family members carrying only the pathogenic variant in the heterozygous state did not demonstrate the myopathic characteristics described in dominant patients. Camptocormia and other severe clinical symptoms were not observed. DISCUSSION: We conclude that the p.Lys254del pathogenic variant per se cannot be solely responsible for camptocormia in dominant patients. Other undisclosed factors may regulate the phenotype associated with the dominant inheritance pattern in CAPN3 pathogenic variant carriers.

Electrodiagnostic subtyping in Guillain-Barré syndrome patients in the International Guillain-Barré Outcome Study.

BACKGROUND AND PURPOSE: Various electrodiagnostic criteria have been developed in Guillain-Barré syndrome (GBS). Their performance in a broad representation of GBS patients has not been evaluated. Motor conduction data from the International GBS Outcome Study (IGOS) cohort were used to compare two widely used criterion sets and relate these to diagnostic amyotrophic lateral sclerosis criteria. METHODS: From the first 1500 patients in IGOS, nerve conduction studies from 1137 (75.8%) were available for the current study. These patients were classified according to nerve conduction studies criteria proposed by Hadden and Rajabally. RESULTS: Of the 1137 studies, 68.3% (N = 777) were classified identically according to criteria by Hadden and Rajabally: 111 (9.8%) axonal, 366 (32.2%) demyelinating, 195 (17.2%) equivocal, 35 (3.1%) inexcitable and 70 (6.2%) normal. Thus, 360 studies (31.7%) were classified differently. The areas of differences were as follows: 155 studies (13.6%) classified as demyelinating by Hadden and axonal by Rajabally; 122 studies (10.7%) classified as demyelinating by Hadden and equivocal by Rajabally; and 75 studies (6.6%) classified as equivocal by Hadden and axonal by Rajabally. Due to more strictly defined cutoffs fewer patients fulfilled demyelinating criteria by Rajabally than by Hadden, making more patients eligible for axonal or equivocal classification by Rajabally. In 234 (68.6%) axonal studies by Rajabally the revised El Escorial (amyotrophic lateral sclerosis) criteria were fulfilled; in axonal cases by Hadden this was 1.8%. CONCLUSIONS AND DISCUSSION: This study shows that electrodiagnosis in GBS is dependent on the criterion set utilized, both of which are based on expert opinion. Reappraisal of electrodiagnostic subtyping in GBS is warranted.

Incidence of major cardiovascular events at 1, 2, and 5 years and mortality in incident patients on peritoneal dialysis regarding their nutritional status by bioimpedanciometry: A multicenter study in Colombia.

BACKGROUND: The nutritional status of incident patients on peritoneal dialysis (PD) has been associated with survival outcomes. Bioimpedanciometry (BCM) enables to establish a nutritional diagnosis, the volume status, and correlates these findings with survival. METHODS: This study used a retrospective multicenter historical cohort. RESULTS: In this study, which included 420 incident patients on peritoneal dialysis with a 5-year follow-up, a cumulative incidence of major adverse cardiovascular events (MACE) of 28.8% was found, being higher in the diabetic population at 36.8%. In regard to the nutritional status in this population, it was found that approximately 44% had altered nutritional status; 34% were found to be in sarcopenia; 6.7% sarcopenic obesity; and 2.8% in obesity (p < 0.001). In the survival analysis, a lower probability of survival was found in patients with overhydration (OH) greater than 3 L (p < 0.001) and in patients with altered nutritional status due to sarcopenia, sarcopenic obesity, and obesity (p 0.016). According to survival in the subgroup of the diabetic population, a lower probability of survival was found in this group of patients (p: 0.011). The overall mortality of the study population was 18%, being higher in the first 2 years, with the most important causes of mortality being cardiovascular. Of the deceased population, 51% were diabetic patients (p: 0.012). CONCLUSION: In incident patients on peritoneal dialysis, sarcopenic obesity, sarcopenia, overhydration status determined by BCM, and having a diagnosis of diabetes are related to a lower probability of survival; MACE outcomes are more frequent in the diabetic population.

Ablation of the carboxy-terminal end of MAMDC2 causes a distinct muscular dystrophy.

The extracellular matrix (ECM) has an important role in the development and maintenance of skeletal muscle, and several muscle diseases are associated with the dysfunction of ECM elements. MAMDC2 is a putative ECM protein and its role in cell proliferation has been investigated in certain cancer types. However, its participation in skeletal muscle physiology has not been previously studied. We describe 17 individuals with an autosomal dominant muscular dystrophy belonging to two unrelated families in which different heterozygous truncating variants in the last exon of MAMDC2 co-segregate correctly with the disease. The radiological aspect of muscle involvement resembles that of COL6 myopathies with fat replacement at the peripheral rim of vastii muscles. In this cohort, a subfascial and peri-tendinous pattern is observed in upper and lower limb muscles. Here we show that MAMDC2 is expressed in adult skeletal muscle and differentiating muscle cells, where it appears to localize to the sarcoplasm and myonuclei. In addition, we show it is secreted by myoblasts and differentiating myotubes into to the extracellular compartment. The last exon encodes a disordered region with a polar residue compositional bias loss of which likely induces a toxic effect of the mutant protein. The precise mechanisms by which the altered MAMDC2 proteins cause disease remains to be determined. MAMDC2 is a skeletal muscle disease-associated protein. Its role in muscle development and ECM-muscle communication remains to be fully elucidated. Screening of the last exon of MAMDC2 should be considered in patients presenting with autosomal dominant muscular dystrophy, particularly in those with a subfascial radiological pattern of muscle involvement.

Small area variations in non-affective first-episode psychosis: the role of socioeconomic and environmental factors.

BACKGROUND: There is strong evidence supporting the association between environmental factors and increased risk of non-affective psychotic disorders. However, the use of sound statistical methods to account for spatial variations associated with environmental risk factors, such as urbanicity, migration, or deprivation, is scarce in the literature. METHODS: We studied the geographical distribution of non-affective first-episode psychosis (NA-FEP) in a northern region of Spain (Navarra) during a 54-month period considering area-level socioeconomic indicators as putative explanatory variables. We used several Bayesian hierarchical Poisson models to smooth the standardized incidence ratios (SIR). We included neighborhood-level variables in the spatial models as covariates. RESULTS: We identified 430 NA-FEP cases over a 54-month period for a population at risk of 365,213 inhabitants per year. NA-FEP incidence risks showed spatial patterning and a significant ecological association with the migrant population, unemployment, and consumption of anxiolytics and antidepressants. The high-risk areas corresponded mostly to peripheral urban regions; very few basic health sectors of rural areas emerged as high-risk areas in the spatial models with covariates. DISCUSSION: Increased rates of unemployment, the migrant population, and consumption of anxiolytics and antidepressants showed significant associations linked to the spatial-geographic incidence of NA-FEP. These results may allow targeting geographical areas to provide preventive interventions that potentially address modifiable environmental risk factors for NA-FEP. Further investigation is needed to understand the mechanisms underlying the associations between environmental risk factors and the incidence of NA-FEP.

Electrodiagnostic subtyping in Guillain-Barré syndrome: Use of criteria in practice based on a survey study in IGOS.

Electrodiagnostic (EDx) studies are helpful in diagnosing and subtyping of Guillain-Barré syndrome (GBS). Published criteria for differentiation into GBS subtypes focus on cutoff values, but other items receive less attention, although they may influence EDx subtyping: (a) extensiveness of EDx testing, (b) nerve-specific considerations, (c) distal compound muscle action potential (CMAP)-amplitude requirements, (d) criteria for conduction block and temporal dispersion. The aims of this study were to investigate how these aspects were approached by neuromuscular EDx experts in practice and how this was done in previously published EDx criteria for GBS. A completed questionnaire was returned by 24 (of 49) members of the electrophysiology expertise group from the International GBS Outcome Study. Six published EDx criteria for GBS subtyping were compared regarding these aspects. The indicated minimal number of motor nerves to study varied among respondents and tended to be more extensive in equivocal than normal studies. Respondents varied considerably regarding usage of compression sites for subtyping (median/wrist, ulnar/elbow, peroneal/fibular head): 29% used all variables from all sites, 13% excluded all sites, and 58% used only some sites and/or variables. Thirty-eight percent of respondents required a minimal distal CMAP amplitude to classify distal motor latency as demyelinating, and 58% did for motor conduction velocity. For proximal/distal CMAP-amplitude ratio and F-wave latency, a requisite minimal CMAP amplitude was more often required (79%). Also, the various published criteria sets showed differences on all items. Practical use of EDx criteria for subtyping GBS vary extensively across respondents, potentially lowering the reproducibility of GBS subtyping.

Autoantibody screening in Guillain-Barré syndrome.

BACKGROUND: Guillain-Barré syndrome (GBS) is an acute inflammatory neuropathy with a heterogeneous presentation. Although some evidences support the role of autoantibodies in its pathogenesis, the target antigens remain unknown in a substantial proportion of GBS patients. The objective of this study is to screen for autoantibodies targeting peripheral nerve components in Guillain-Barré syndrome. METHODS: Autoantibody screening was performed in serum samples from all GBS patients included in the International GBS Outcome study by 11 different Spanish centres. The screening included testing for anti-ganglioside antibodies, anti-nodo/paranodal antibodies, immunocytochemistry on neuroblastoma-derived human motor neurons and murine dorsal root ganglia (DRG) neurons, and immunohistochemistry on monkey peripheral nerve sections. We analysed the staining patterns of patients and controls. The prognostic value of anti-ganglioside antibodies was also analysed. RESULTS: None of the GBS patients (n = 100) reacted against the nodo/paranodal proteins tested, and 61 (61%) were positive for, at least, one anti-ganglioside antibody. GBS sera reacted strongly against DRG neurons more frequently than controls both with IgG (6% vs 0%; p = 0.03) and IgM (11% vs 2.2%; p = 0.02) immunodetection. No differences were observed in the proportion of patients reacting against neuroblastoma-derived human motor neurons. Reactivity against monkey nerve tissue was frequently detected both in patients and controls, but specific patterns were only detected in GBS patients: IgG from 13 (13%) patients reacted strongly against Schwann cells. Finally, we confirmed that IgG anti-GM1 antibodies are associated with poorer outcomes independently of other known prognostic factors. CONCLUSION: Our study confirms that (1) GBS patients display a heterogeneous repertoire of autoantibodies targeting nerve cells and structures; (2) gangliosides are the most frequent antigens in GBS patients and have a prognostic value; (3) further antigen-discovery experiments may elucidate other potential antigens in GBS.

Clinical characteristics and outcomes of thymoma-associated myasthenia gravis.

BACKGROUND AND PURPOSE: Prognosis of myasthenia gravis (MG) in patients with thymoma is not well established. Moreover, it is not clear whether thymoma recurrence or unresectable lesions entail a worse prognosis of MG. METHODS: This multicenter study was based on data from a Spanish neurologist-driven MG registry. All patients were aged >18 years at onset and had anti-acetylcholine receptor antibodies. We compared the clinical data of thymomatous and nonthymomatous patients. Prognosis of patients with recurrent or nonresectable thymomas was assessed. RESULTS: We included 964 patients from 15 hospitals; 148 (15.4%) had thymoma-associated MG. Median follow-up time was 4.6 years. At onset, thymoma-associated MG patients were younger (52.0 vs. 60.4 years, p < 0.001), had more generalized symptoms (odds ratio [OR]: 3.02, 95% confidence interval [CI]: 1.95-4.68, p < 0.001) and more severe clinical forms according to the Myasthenia Gravis Foundation of America (MGFA) scale (OR: 1.6, 95% CI: 1.15-2.21, p = 0.005). Disease severity based on MGFA postintervention status (MGFA-PIS) was higher in thymomatous patients at 1 year, 5 years, and the end of follow-up. Treatment refractoriness and mortality were also higher (OR: 2.28, 95% CI: 1.43-3.63, p = 0.001; hazard ratio: 2.46, 95% CI: 1.47-4.14, p = 0.001). Myasthenic symptoms worsened in 13 of 27 patients with recurrences, but differences in long-term severity were not significant. Fifteen thymomatous patients had nonresectable thymomas with worse MGFA-PIS and higher mortality at the end of follow-up. CONCLUSIONS: Thymoma-associated MG patients had more severe myasthenic symptoms and worse prognosis. Thymoma recurrence was frequently associated with transient worsening of MG, but long-term prognosis did not differ from nonrecurrent thymoma. Patients with nonresectable thymoma tended to present severe forms of MG.

Clinical, pathological and genetic spectrum in 89 cases of mitochondrial progressive external ophthalmoplegia.

BACKGROUND: Mitochondrial progressive external ophthalmoplegia (PEO) encompasses a broad spectrum of clinical and genetic disorders. We describe the phenotypic subtypes of PEO and its correlation with molecular defects and propose a diagnostic algorithm. METHODS: Retrospective analysis of the clinical, pathological and genetic features of 89 cases. RESULTS: Three main phenotypes were found: 'pure PEO' (42%), consisting of isolated palpebral ptosis with ophthalmoparesis; Kearns-Sayre syndrome (10%); and 'PEO plus', which associates extraocular symptoms, distinguishing the following subtypes: : myopathic (33%), bulbar (12%) and others (3%). Muscle biopsy was the most accurate test, showing mitochondrial changes in 95%. Genetic diagnosis was achieved in 96% of the patients. Single large-scale mitochondrial DNA (mtDNA) deletion was the most frequent finding (63%), followed by multiple mtDNA deletions (26%) due to mutations in TWNK (n=8), POLG (n=7), TK2 (n=6) or RRM2B (n=2) genes, and point mtDNA mutations (7%). Three new likely pathogenic mutations were identified in the TWNK and MT-TN genes. CONCLUSIONS: Phenotype-genotype correlations cannot be brought in mitochondrial PEO. Muscle biopsy should be the first step in the diagnostic flow of PEO when mitochondrial aetiology is suspected since it also enables the study of mtDNA rearrangements. If no mtDNA deletions are identified, whole mtDNA sequencing should be performed.

Serum neurofilament light chain predicts long-term prognosis in Guillain-Barré syndrome patients.

OBJECTIVE: To study baseline serum neurofilament light chain (sNfL) levels as a prognostic biomarker in Guillain-Barré syndrome (GBS). METHODS: We measured NfL in serum (98 samples) and cerebrospinal fluid (CSF) (24 samples) of patients with GBS prospectively included in the International GBS Outcome Study (IGOS) in Spain using single-molecule array (SiMoA) and compared them with 53 healthy controls (HCs). We performed multivariable regression to analyse the association between sNfL levels and functional outcome at 1 year. RESULTS: Patients with GBS had higher NfL levels than HC in serum (55.49 pg/mL vs 9.83 pg/mL, p<0.0001) and CSF (1308.5 pg/mL vs 440.24 pg/mL, p=0.034). Patients with preceding diarrhoea had higher sNfL than patients with respiratory symptoms or no preceding infection (134.90 pg/mL vs 47.86 pg/mL vs 38.02 pg/mL, p=0.016). sNfL levels correlated with Guillain-Barré Syndrome Disability Score and Inflammatory Rasch-built Overall Disability Scale (I-RODS) at every timepoint. Patients with pure motor variant and Miller Fisher syndrome showed higher sNfL levels than patients with sensorimotor GBS (162.18 pg/mL vs 95.50 pg/mL vs 38.02 pg/mL, p=0.025). Patients with acute motor axonal neuropathy cute motor axonal neuropathy had higher sNfL levels than other variants (190.55 pg/mL vs 46.79 pg/mL, p=0.013). sNfL returned to normal levels at 1 year. High baseline sNfL levels were associated with inability to run (OR=1.65, 95% CI 1.14 to 2.40, p=0.009) and lower I-RODS (ß -2.60, 95% CI -4.66 to -0.54, p=0.014) at 1 year. Cut-off points predicting clinically relevant outcomes at 1 year with high specificity were calculated: inability to walk independently (>319 pg/mL), inability to run (>248 pg/mL) and ability to run (<34 pg/mL). CONCLUSION: Baseline sNfL levels are increased in patients with GBS, are associated with disease severity and axonal variants and have an independent prognostic value in patients with GBS.

Concomitant Medications and Risk of Chemotherapy-Induced Peripheral Neuropathy.

BACKGROUND: Peripheral neuropathy is the dose-limiting toxicity of many oncology drugs, including paclitaxel. There is large interindividual variability in the neuropathy, and several risk factors have been proposed; however, many have not been replicated. Here we present a comprehensive study aimed at identifying treatment and physiopathology-related paclitaxel-induced neuropathy risk factors in a large cohort of well-characterized patients. PATIENTS AND METHODS: Analyses included 503 patients with breast or ovarian cancer who received paclitaxel treatment. Paclitaxel dose modifications caused by the neuropathy were extracted from medical records and patients self-reported neuropathy symptoms were collected. Multivariate logistic regression analyses were performed to identify concomitant medications and comorbidities associated with paclitaxel-induced neuropathy. RESULTS: Older patients had higher neuropathy: for each increase of 1 year of age, the risk of dose modifications and grade 3 neuropathy increased 4% and 5%, respectively. Cardiovascular drugs increased the risk of paclitaxel dose reductions (odds ratio [OR], 2.51; p = .006), with a stronger association for beta-adrenergic antagonists. The total number of concomitant medications also showed an association with dose modifications (OR, 1.25; p = .012 for each concomitant drug increase). A dose modification predictive model that included the new identified factors gave an area under the curve of 0.74 (p = 1.07 × 10-10). Preexisting nerve compression syndromes seemed to increase neuropathy risk. CONCLUSION: Baseline characteristics of the patients, including age and concomitant medications, could be used to identify individuals at high risk of neuropathy, personalizing chemotherapy treatment and reducing the risk of severe neuropathy. IMPLICATIONS FOR PRACTICE: Peripheral neuropathy is a common adverse effect of many cancer drugs, including chemotherapeutics, targeted therapies, and immune checkpoint inhibitors. About 40% of survivors of cancer have functional deficits caused by this toxicity, some of them irreversible. Currently, there are no effective treatments to prevent or treat this neuropathy. This study, performed in a large cohort of well-characterized patients homogenously treated with paclitaxel, identified concomitant medications, comorbidities, and demographic factors associated with peripheral neuropathy. These factors could serve to identify patients at high risk of severe neuropathy for whom alternative non-neurotoxic alternatives may be considered.

Muscle MRI in a large cohort of patients with oculopharyngeal muscular dystrophy.

BACKGROUND AND OBJECTIVE: Oculopharyngeal muscular dystrophy (OPMD) is a genetic disorder caused by an abnormal expansion of GCN triplets within the PABPN1 gene. Previous descriptions have focused on lower limb muscles in small cohorts of patients with OPMD, but larger imaging studies have not been performed. Previous imaging studies have been too small to be able to correlate imaging findings to genetic and clinical data. METHODS: We present cross-sectional, T1-weighted muscle MRI and CT-scan data from 168 patients with genetically confirmed OPMD. We have analysed the pattern of muscle involvement in the disease using hierarchical analysis and presented it as heatmaps. Results of the scans were correlated with genetic and clinical data. RESULTS: Fatty replacement was identified in 96.7% of all symptomatic patients. The tongue, the adductor magnus and the soleus were the most commonly affected muscles. Muscle pathology on MRI correlated positively with disease duration and functional impairment. CONCLUSIONS: We have described a pattern that can be considered characteristic of OPMD. An early combination of fat replacement in the tongue, adductor magnus and soleus can be helpful for differential diagnosis. The findings suggest the natural history of the disease from a radiological point of view. The information generated by this study is of high diagnostic value and important for clinical trial development.

Genetic polymorphisms of SCN9A are associated with oxaliplatin-induced neuropathy.

BACKGROUND: Oxaliplatin is a chemotherapy agent active against digestive tumors. Peripheral neuropathy is one of the most important dose-limiting toxicity of this drug. It occurs in around 60-80% of the patients, and 15% of them develop severe neuropathy. The pathophysiology of oxaliplatin neurotoxicity remains unclear. SCN9A is a gene codifying for a subtype sodium channel (type IX, subunit α) and mutations in this gene are involved in neuropathic perception. In this study we investigated whether SCN9A genetic variants were associated with risk of neurotoxicity in patients diagnosed of cancer on treatment with oxaliplatin. METHODS: Blood samples from 94 patients diagnosed of digestive cancer that had received oxaliplatin in adjuvant or metastatic setting were obtained from three hospitals in Madrid. These patients were classified into two groups: "cases" developed oxaliplatin-induced grade 3-4 neuropathy (n = 48), and "controls" (n = 46) had no neuropathy or grade 1. The neuropathy was evaluated by an expert neurologist and included a clinical examination and classification according to validated neurological scales: National Cancer Institute Common Toxicity Criteria (NCI-CTC), Oxaliplatin-Specific Neurotoxicity Scale (OSNS) and Total Neuropathy score (TNS). Genotyping was performed for 3 SCN9A missense polymorphisms: rs6746030 (R1150W), rs74401238 (R1110Q) and rs41268673 (P610T), and associations between genotypes and neuropathy were evaluated. RESULTS: We found that SCN9A rs6746030 was associated with protection for severe neuropathy (OR = 0.39, 95% CI = 0.16-0.96; p = 0.041). Multivariate analysis adjusting for diabetes provided similar results (p = 0.036). No significant differences in neuropathy risk were detected for rs74401238 and rs41268673. CONCLUSION: SCN9A rs6746030 was associated with protection for severe oxaliplatin-induced peripheral neuropathy. The validation of this exploratory study is ongoing in an independent series.

Development of a panel of genome-wide ancestry informative markers to study admixture throughout the Americas.

Most individuals throughout the Americas are admixed descendants of Native American, European, and African ancestors. Complex historical factors have resulted in varying proportions of ancestral contributions between individuals within and among ethnic groups. We developed a panel of 446 ancestry informative markers (AIMs) optimized to estimate ancestral proportions in individuals and populations throughout Latin America. We used genome-wide data from 953 individuals from diverse African, European, and Native American populations to select AIMs optimized for each of the three main continental populations that form the basis of modern Latin American populations. We selected markers on the basis of locus-specific branch length to be informative, well distributed throughout the genome, capable of being genotyped on widely available commercial platforms, and applicable throughout the Americas by minimizing within-continent heterogeneity. We then validated the panel in samples from four admixed populations by comparing ancestry estimates based on the AIMs panel to estimates based on genome-wide association study (GWAS) data. The panel provided balanced discriminatory power among the three ancestral populations and accurate estimates of individual ancestry proportions (R² > 0.9 for ancestral components with significant between-subject variance). Finally, we genotyped samples from 18 populations from Latin America using the AIMs panel and estimated variability in ancestry within and between these populations. This panel and its reference genotype information will be useful resources to explore population history of admixture in Latin America and to correct for the potential effects of population stratification in admixed samples in the region.

Brain metastases and lung cancer: molecular biology, natural history, prediction of response and efficacy of immunotherapy.

Brain metastases stemming from lung cancer represent a common and challenging complication that significantly impacts patients' overall health. The migration of these cancerous cells from lung lesions to the central nervous system is facilitated by diverse molecular changes and a specific environment that supports their affinity for neural tissues. The advent of immunotherapy and its varied combinations in non-small cell lung cancer has notably improved patient survival rates, even in cases involving brain metastases. These therapies exhibit enhanced penetration into the central nervous system compared to traditional chemotherapy. This review outlines the molecular mechanisms underlying the development of brain metastases in lung cancer and explores the efficacy of novel immunotherapy approaches and their combinations.

Effectiveness of the early intervention service for first-episode psychosis in Navarra (PEPsNa): Broadening the scope of outcome measures.

BACKGROUND: This study compares the effectiveness of a new early intervention service for firstepisode psychosis (FEP) in patients under conventional treatment. Six primary and 10 secondary outcome measures are used to better characterize the comparative effectiveness between two FEP groups. METHODS: This study plans to enroll 250 patients aged 15-55 years with FEP from all inpatient and outpatient mental health services and primary health care from January 2020 until December 2022. The control group will be composed of 130 FEP patients treated in mental health centers in the 2 years prior to the start of PEPsNa (Programa de Primeros Episodios de Psicosis de Navarra). The primary outcome measures are symptomatic remission, functional recovery, personal recovery, cognitive performance, functional capacity in real-world settings, and costs. The secondary outcome measures are duration of untreated psychosis, substance abuse rate, antipsychotic monotherapy, minimal effective dose of antipsychotic drugs, therapeutic alliance, drop-out rate, number of relapses, global mortality and suicidality, resource use, and general satisfaction in the program. DISCUSSION: This study arises from the growing need to broaden the scope of outcome measures in FEP patients and to account for unmet needs of recovery for FEPs. It aims to contribute in the dissemination of the NAVIGATE model in Europe and to provide new evidence of the effectiveness of early intervention services for stakeholders of the National Health Service.

CSF Findings in Relation to Clinical Characteristics, Subtype, and Disease Course in Patients With Guillain-Barré Syndrome.

BACKGROUND AND OBJECTIVES: To investigate CSF findings in relation to clinical and electrodiagnostic subtypes, severity, and outcome of Guillain-Barré syndrome (GBS) based on 1,500 patients in the International GBS Outcome Study. METHODS: Albuminocytologic dissociation (ACD) was defined as an increased protein level (>0.45 g/L) in the absence of elevated white cell count (<50 cells/µL). We excluded 124 (8%) patients because of other diagnoses, protocol violation, or insufficient data. The CSF was examined in 1,231 patients (89%). RESULTS: In 846 (70%) patients, CSF examination showed ACD, which increased with time from weakness onset: ≤4 days 57%, >4 days 84%. High CSF protein levels were associated with a demyelinating subtype, proximal or global muscle weakness, and a reduced likelihood of being able to run at week 2 (odds ratio [OR] 0.42, 95% CI 0.25-0.70; p = 0.001) and week 4 (OR 0.44, 95% CI 0.27-0.72; p = 0.001). Patients with the Miller Fisher syndrome, distal predominant weakness, and normal or equivocal nerve conduction studies were more likely to have lower CSF protein levels. CSF cell count was <5 cells/µL in 1,005 patients (83%), 5-49 cells/µL in 200 patients (16%), and ≥50 cells/µL in 13 patients (1%). DISCUSSION: ACD is a common finding in GBS, but normal protein levels do not exclude this diagnosis. High CSF protein level is associated with an early severe disease course and a demyelinating subtype. Elevated CSF cell count, rarely ≥50 cells/µL, is compatible with GBS after a thorough exclusion of alternative diagnoses. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that CSF ACD (defined by the Brighton Collaboration) is common in patients with GBS.

Electrodiagnosis of Guillain-Barre syndrome in the International GBS Outcome Study: Differences in methods and reference values.

OBJECTIVE: To describe the heterogeneity of electrodiagnostic (EDx) studies in Guillain-Barré syndrome (GBS) patients collected as part of the International GBS Outcome Study (IGOS). METHODS: Prospectively collected clinical and EDx data were available in 957 IGOS patients from 115 centers. Only the first EDx study was included in the current analysis. RESULTS: Median timing of the EDx study was 7 days (interquartile range 4-11) from symptom onset. Methodology varied between centers, countries and regions. Reference values from the responding 103 centers were derived locally in 49%, from publications in 37% and from a combination of these in the remaining 15%. Amplitude measurement in the EDx studies (baseline-to-peak or peak-to-peak) differed from the way this was done in the reference values, in 22% of motor and 39% of sensory conduction. There was marked variability in both motor and sensory reference values, although only a few outliers accounted for this. CONCLUSIONS: Our study showed extensive variation in the clinical practice of EDx in GBS patients among IGOS centers across the regions. SIGNIFICANCE: Besides EDx variation in GBS patients participating in IGOS, this diversity is likely to be present in other neuromuscular disorders and centers. This underlines the need for standardization of EDx in future multinational GBS studies.

Drug-refractory myasthenia gravis: Clinical characteristics, treatments, and outcome.

OBJECTIVE: To describe the clinical characteristics and outcomes in patients with refractory myasthenia gravis (MG) and to determine the effectiveness and side effects of the drugs used for their treatment. METHODS: This observational retrospective cross-sectional multicenter study was based on data from the Spanish MG Registry (NMD-ES). Patients were considered refractory when their MG Foundation of America post-interventional status (MGFA-PIS) was unchanged or worse after corticosteroids and two or more other immunosuppressive agents. Clinical and immunologic characteristics of drug-refractory patients, efficiency and toxicity of drugs used, and outcome (MGFA-PIS) at end of follow-up were studied. RESULTS: We included 990 patients from 15 hospitals. Eighty-four patients (68 of 842 anti-acetylcholine receptor [AChR], 5 of 26 anti-muscle-specific tyrosine kinase [MusK], 10 of 120 seronegative, and 1 of 2 double-seropositive patients) were drug refractory. Drug-refractory patients were more frequently women (p < 0.0001), younger at onset (p < 0.0001), and anti-MuSK positive (p = 0.037). Moreover, they more frequently presented a generalized form of the disease, bulbar symptoms, and life-threatening events (p < 0.0001; p = 0.018; and p = 0.002, respectively) than non-drug-refractory patients. Mean follow-up was 9.8 years (SD 4.5). Twenty-four (50%) refractory patients had side effects to one or more of the drugs. At the end of follow-up, 42.9% of drug-refractory patients (42.6% of anti-AChR, 100% of anti-MuSK, and 10% of seronegative patients) and 79.8% of non-drug-refractory patients (p < 0.0001) achieved remission or had minimal manifestations. Eighty percent of drug-refractory-seronegative patients did not respond to any drug tested. INTERPRETATION: In this study, 8.5% of MG patients were drug-refractory. New more specific drugs are needed to treat drug-refractory MG patients.