Variable Phenotype Research Articles

A novel RYR1 pathogenic variant − Common among Libyan Jews and associated with a broad phenotypic spectrum

Mutated skeletal muscle ryanodine receptor-1 (RYR1) gene is associated with a spectrum of autosomal dominant and recessive RyR1-related disorders with a wide phenotype. This report describes a variable phenotype associated with a previously unreported RYR1 frameshift pathogenic variant, (NM_000540.2) c.12815_12825del; p.Ala4272Glyfs*307, common in Libyan Jews. Clinical and genetic features of 14 carriers from 8 unrelated families were collected. There were 12 heterozygotes and 2 compound heterozygotes. Six heterozygotes (median age 49.8) were asymptomatic, and six (median age 24.5) presented with myopathy (n = 3) or severe arthrogryposis-like features, severe scoliosis, pes planus, post-anesthesia malignant hyperthermia, or cystic hygroma (in a fetus) (n = 1 each). None had an abnormal echocardiogram study or elevated creatine phosphokinase (CPK) levels. One bi-allelic carrier had a severe skeletal phenotype and myopathy; the other was a fetus with a cystic hygroma. Assessment of variant frequency in 447 Libyan Jews who underwent exome testing for unrelated reason yielded a prevalence of 1:55. The RYR1 p.Ala4272Glyfs*307 variant is common in Libyan Jews. It is associated with a broad phenotypic spectrum, with possible presentation among heterozygotes. Further genotype-phenotype studies are essential to delineate the clinical significance of the variant in mono- and bi-allelic carriers.

Biallelic variants in Plexin B2 (PLXNB2) cause amelogenesis imperfecta, hearing loss and intellectual disability

BackgroundPlexins are large transmembrane receptors for the semaphorin family of signalling proteins. Semaphorin-plexin signalling controls cellular interactions that are critical during development as well as in adult life stages. Nine...

Fractal analysis of left ventricular trabeculae in heart failure with preserved ejection fraction patients with multivessel coronary artery disease

ObjectivesEndocardial trabeculae undergo varicose changes and hyperplasia in response to hemodynamic influences and are a variable phenotype reflecting changes in disease. Fractal analysis has been used to analyze the complexity of endocardial trabeculae in a variety of cardiomyopathies. The aim of this paper was to quantify the myocardial trabecular complexity through fractal analysis and to investigate its predictive value for the diagnosis of heart failure with preserved ejection fraction (HFpEF) in patients with multivessel coronary artery disease (CAD).MethodsThe retrospective study population consisted of 97 patients with multivessel CAD, 39 of them were diagnosed with HFpEF, while 46 healthy volunteers were recruited as controls. Fractal dimension (FD) was obtained through fractal analysis of endocardial trabeculae on LV short-axis cine images. Logistic regression analyses were used to confirm the predictors and compare different prediction models.ResultsMean basal FD was significantly higher in patients with HFpEF than in patients without HFpEF or in the healthy group (median: 1.289; IQR: 0.078; p < 0.05). Mean basal FD was also a significant independent predictor in univariate and multivariate logistic regression (OR: 1.107 and 1.043, p < 0.05). Furthermore, adding FD to the prediction model improved the calibration and accuracy of the model (c-index: 0.806).ConclusionThe left ventricular FD obtained with fractal analysis can reflect the complexity of myocardial trabeculae and has an independent predictive value for the diagnosis of HFpEF in patients with multivessel CAD. Including FD into the diagnostic model can help improve the diagnosis.Critical relevance statementDifferences show in the complexity of endocardial trabeculae in multivessel coronary artery disease patients, and obtaining fractal dimensions (FD) by fractal analysis can help identify heart failure with preserved ejection fraction (HFpEF) patients.Key PointsThe complexity of myocardial trabeculae differs among patients with multivessel coronary artery disease.Left ventricular fractal dimensions can reflect the complexity of the myocardial trabecular.Fractal dimensions have predictive value for the diagnosis of heart failure with preserved ejection fraction.Graphical

Phenotypes of cytomegalovirus genetic variants encountered in a letermovir clinical trial illustrate the importance of genotyping validation

Emergence of drug resistance is rare after use of letermovir (LMV) as prophylaxis for post-transplant cytomegalovirus (CMV) infection. In a recent study involving renal transplant recipients, no known LMV resistance mutations were detected in those receiving LMV prophylaxis. However, uncharacterized viral amino acid substitutions were detected in LMV recipients by deep sequencing in viral subpopulations of 5%–7%, at codons previously associated with drug resistance: UL56 S229Y (n = 1), UL56 M329I (n = 9) and UL89 D344Y (n = 5). Phenotypic analysis of these mutations in a cloned laboratory CMV strain showed that S229Y conferred a 2-fold increase in LMV EC50, M329I conferred no LMV resistance, and D344Y knocked out viral viability that was restored after the nonviable clone was reverted to wild type D344. As in previous CMV antiviral trials, the detection of nonviable mutations, even in multiple study subjects, raises strong suspicion of genotyping artifacts and encourages the use of replicate testing for authentication of atypical mutation readouts. The non-viability of UL89 D344Y also confirms the biologically important locus of the D344E substitution that confers resistance to benzimidazole CMV terminase complex inhibitors, but does not feature prominently in LMV resistance.

Effects of Drought Stress on Abscisic Acid Content and Its Related Transcripts in Allium fistulosum—A. cepa Monosomic Addition Lines

Climate change has resulted in an increased demand for Japanese bunching onions (Allium fistulosum L., genomes FF) with drought resistance. A complete set of alien monosomic addition lines of A. fistulosum with extra chromosomes from shallot (A. cepa L. Aggregatum group, AA), represented as FF + 1A–FF + 8A, displays a variety of phenotypes that significantly differ from those of the recipient species. In this study, we investigated the impact of drought stress on abscisic acid (ABA) and its precursor, β-carotene, utilizing this complete set. In addition, we analyzed the expression levels of genes related to ABA biosynthesis, catabolism, and drought stress signal transduction in FF + 1A and FF + 6A, which show characteristic variations in ABA accumulation. A number of unigenes related to ABA were selected through a database using Allium TDB. Under drought conditions, FF + 1A exhibited significantly higher ABA and β-carotene content compared with FF. Additionally, the expression levels of all ABA-related genes in FF + 1A were higher than those in FF. These results indicate that the addition of chromosome 1A from shallot caused the high expression of ABA biosynthesis genes, leading to increased levels of ABA accumulation. Therefore, it is expected that the introduction of alien genes from the shallot will upwardly modify ABA content, which is directly related to stomatal closure, leading to drought stress tolerance in FF.

Targeting autoimmune mechanisms by precision medicine in Myasthenia Gravis.

Myasthenia Gravis (MG) is a chronic disabling autoimmune disease caused by autoantibodies to the neuromuscular junction (NMJ), characterized clinically by fluctuating weakness and early fatigability of ocular, skeletal and bulbar muscles. Despite being commonly considered a prototypic autoimmune disorder, MG is a complex and heterogeneous condition, presenting with variable clinical phenotypes, likely due to distinct pathophysiological settings related with different immunoreactivities, symptoms' distribution, disease severity, age at onset, thymic histopathology and response to therapies. Current treatment of MG based on international consensus guidelines allows to effectively control symptoms, but most patients do not reach complete stable remission and require life-long immunosuppressive (IS) therapies. Moreover, a proportion of them is refractory to conventional IS treatment, highlighting the need for more specific and tailored strategies. Precision medicine is a new frontier of medicine that promises to greatly increase therapeutic success in several diseases, including autoimmune conditions. In MG, B cell activation, antibody recycling and NMJ damage by the complement system are crucial mechanisms, and their targeting by innovative biological drugs has been proven to be effective and safe in clinical trials. The switch from conventional IS to novel precision medicine approaches based on these drugs could prospectively and significantly improve MG care. In this review, we provide an overview of key immunopathogenetic processes underlying MG, and discuss on emerging biological drugs targeting them. We also discuss on future direction of research to address the need for patients' stratification in endotypes according with genetic and molecular biomarkers for successful clinical decision making within precision medicine workflow.

Predictors associated with the rate of progression of nigrostriatal degeneration in Parkinson's disease.

Parkinson's disease (PD) manifests as a wide variety of clinical phenotypes and its progression varies greatly. However, the factors associated with different disease progression remain largely unknown. In this retrospective cohort study, we enrolled 113 patients who underwent 18F-FP-CIT PET scan twice. Given the negative exponential progression pattern of dopamine loss in PD, we applied the natural logarithm to the specific binding ratio (SBR) of two consecutive 18F-FP-CIT PET scans and conducted linear mixed model to calculate individual slope to define the progression rate of nigrostriatal degeneration. We investigated the clinical and dopamine transporter (DAT) availability patterns associated with the progression rate of dopamine depletion in each striatal sub-region. More symmetric parkinsonism, the presence of dyslipidemia, lower K-MMSE total score, and lower anteroposterior gradient of the mean putaminal SBR were associated with faster progression rate of dopamine depletion in the caudate nucleus. More symmetric parkinsonism and lower anteroposterior gradient of the mean putaminal SBR were associated with faster depletion of dopamine in the anterior putamen. Older age at onset, more symmetric parkinsonism, the presence of dyslipidemia, and lower anteroposterior gradient of the mean putaminal SBR were associated with faster progression rate of dopamine depletion in the posterior putamen. Lower striatal mean SBR predicted the development of LID, while lower mean SBR in the caudate nuclei predicted the development of dementia. Our results suggest that the evaluation of baseline clinical features and patterns of DAT availability can predict the progression of PD and its prognosis.

Early onset LGMDR19 with unusual features related to GMPPB gene in South Indian siblings with variable phenotype

Guanosine diphosphate mannose (GDP-mannose) pyrophosphorylase B (GMPPB) is a cytoplasmic enzyme that catalyzes the synthesis of GDP-mannose, a crucial substrate for several glycosylation pathways. Reports of pathogenic variants in the GMPPB gene are infrequent. As of April 2023, 109 cases with pathogenic variants in the GMPPB gene have been reported worldwide. Here, we present two siblings born of consanguineous parentage from Southern India. This is a retrospective study on genetically confirmed siblings with GMPPB pathogenic variants. The siblings, a 15-year-old girl, and a 13-year-old boy, presented with progressive limb-girdle weakness and cataracts from early childhood. The girl had exertion-induced breathlessness and mental subnormality. Creatine kinase levels were 5750 and 4320 IU/L. An echocardiogram of the heart revealed global hypokinesia, moderate left ventricular dysfunction, and mild mitral regurgitation with dilation of the left atrium and left ventricle in the girl child. Exome sequencing showed a homozygous pathogenic variant (NM_021971.4 (GMPPB): c.358A&gt;G (p.Met120Val) in Exon 4 of GMPPB gene in both the siblings. Thus, we report an unusual early onset LGMD phenotype of GMPPB-related disorder with cardiac involvement and cataracts from a single family.

Developmental Disruption of Mef2c in Medial Ganglionic Eminence–Derived Cortical Inhibitory Interneurons Impairs Cellular and Circuit Function

BackgroundMEF2C is strongly linked to various neurodevelopmental disorders including autism, intellectual disability, schizophrenia, and attention-deficit/hyperactivity disorder. Mice that constitutively lack 1 copy of Mef2c or selectively lack both copies of Mef2c in cortical excitatory neurons display a variety of behavioral phenotypes associated with neurodevelopmental disorders. The MEF2C protein is a transcription factor necessary for cellular development and synaptic modulation of excitatory neurons. MEF2C is also expressed in a subset of cortical GABAergic (gamma-aminobutyric acidergic) inhibitory neurons, but its function in those cell types remains largely unknown. MethodsUsing conditional deletions of the Mef2c gene in mice, we investigated the role of MEF2C in parvalbumin-expressing interneurons (PV-INs), the largest subpopulation of cortical GABAergic cells, at 2 developmental time points. We performed slice electrophysiology, in vivo recordings, and behavior assays to test how embryonic and late postnatal loss of MEF2C from GABAergic INs impacts their survival and maturation and alters brain function and behavior. ResultsLoss of MEF2C from PV-INs during embryonic, but not late postnatal, development resulted in reduced PV-IN number and failure of PV-INs to molecularly and synaptically mature. In association with these deficits, early loss of MEF2C in GABAergic INs led to abnormal cortical network activity, hyperactive and stereotypic behavior, and impaired cognitive and social behavior. ConclusionsMEF2C expression is critical for the development of cortical GABAergic INs, particularly PV-INs. Embryonic loss of function of MEF2C mediates dysfunction of GABAergic INs, leading to altered in vivo patterns of cortical activity and behavioral phenotypes associated with neurodevelopmental disorders.

Characterization of Von Hippel Lindau gene variants by race.

e15158 Background: Autosomal dominant (AD) pathogenic/ likely pathogenic (P/LP) variants in the VHL gene cause Von Hippel Lindau syndrome, historically studied in White populations. We aimed to characterize VHL variants and disease phenotypes in both Non-White (NW) patients, which include Asian and African-American (AA), and in Non-Hispanic White (NHW) patients. Methods: Patients undergoing germline genetic testing (GGT) at Invitae Corporation from November 2014 to March 2022, carrying a P/LP AD variant in VHL gene were identified. Demographic and clinical data were obtained from Test requisition forms. Fisher's exact test and Wilcoxon rank-sum tests were performed for categorical and continuous variables, respectively, to compare groups. Results: The final analysis included 363 patients (NW=27%). Hemangioblastoma was predominant in all groups (NHW=13%, NW=27%, p=0.004). Breast cancer exclusively occurred in NHW patients (7%, p=0.019). NHW and NW patients had a higher family history of breast cancer (NHW=7%, NW=1%, p=0.046) and hemangioblastoma (NHW=3%, NW=8%, p=0.037), respectively. Distribution of VHL variants between NW and NHW patients varied significantly (p&lt;0.001, Indels p=0.009, substitution variants p&lt;0.001). Deletion exon 2 was predominant in all groups (NHW=15%, NW=35%) P.Leu188Val was exclusive to NHW patients (26%)while p.Arg167Trp (NHW=6%, NW=11%) and p.Arg167Gln (NHW=2%, NW=10%) were more common in NW patients. Several unique variants in AA and Hispanic patients were seen. Conclusions: This study reveals differences in P/LP VHL variant distribution and disease phenotype between NHW and NW races. Ethnicity-specific characterization uncovers unique variants in AA and Hispanic patients. This dataset informs future research on VHL disease and treatment in diverse populations.

Expanding the RNA polymerase biocatalyst solution space for mRNA manufacture.

All mRNA products are currently manufactured in in vitro transcription (IVT) reactions that utilize single-subunit RNA polymerase (RNAP) biocatalysts. Although it is known that discrete polymerases exhibit highly variable bioproduction phenotypes, including different relative processivity rates and impurity generation profiles, only a handful of enzymes are generally available for mRNA biosynthesis. This limited RNAP toolbox restricts strategies to design and troubleshoot new mRNA manufacturing processes, which is particularly undesirable given the continuing diversification of mRNA product lines toward larger and more complex molecules. Herein, we describe development of a high-throughput RNAP screening platform, comprising complementary in silico and in vitro testing modules, that enables functional characterization of large enzyme libraries. Utilizing this system, we identified eight novel sequence-diverse RNAPs, with associated active cognate promoters, and subsequently validated their performance as recombinant enzymes in IVT-based mRNA production processes. By increasing the number of available characterized functional RNAPs by more than 130% and providing a platform to rapidly identify further potentially useful enzymes, this work significantly expands the RNAP biocatalyst solution space for mRNA manufacture, thereby enhancing the capability for application-specific and molecule-specific optimization of both product yield and quality.

A treatable case of hereditary transthyretin amyloidosis with polyneuropathy masquerading as motor neuron disease

Hereditary transthyretin amyloidosis is a progressive, life-threatening disease that typically presents as length-dependent symmetric axonal sensorimotor polyneuropathy, restrictive cardiomyopathy, or a combination of both. In this case report, we describe a 50-year-old gentleman with a rare motor phenotypic variant of hereditary transthyretin amyloidosis with polyneuropathy (hATTR-PN) masquerading as motor neuron disease. This case represents the first reported association between the motor phenotypic variants of hATTR-PN and mutations involving p.Ala117Ser, a mutation prevalent in the Chinese population.

Predicting Non-Alcoholic Steatohepatitis: A Lipidomics-Driven Machine Learning Approach.

Nonalcoholic fatty liver disease (NAFLD), nowadays the most prevalent chronic liver disease in Western countries, is characterized by a variable phenotype ranging from steatosis to nonalcoholic steatohepatitis (NASH). Intracellular lipid accumulation is considered the hallmark of NAFLD and is associated with lipotoxicity and inflammation, as well as increased oxidative stress levels. In this study, a lipidomic approach was used to investigate the plasma lipidome of 12 NASH patients, 10 Nonalcoholic Fatty Liver (NAFL) patients, and 15 healthy controls, revealing significant alterations in lipid classes, such as glycerolipids and glycerophospholipids, as well as fatty acid compositions in the context of steatosis and steatohepatitis. A machine learning XGBoost algorithm identified a panel of 15 plasma biomarkers, including HOMA-IR, BMI, platelets count, LDL-c, ferritin, AST, FA 12:0, FA 18:3 ω3, FA 20:4 ω6/FA 20:5 ω3, CAR 4:0, LPC 20:4, LPC O-16:1, LPE 18:0, DG 18:1_18:2, and CE 20:4 for predicting steatohepatitis. This research offers insights into the connection between imbalanced lipid metabolism and the formation and progression of NAFL D, while also supporting previous research findings. Future studies on lipid metabolism could lead to new therapeutic approaches and enhanced risk assessment methods, as the shift from isolated steatosis to NASH is currently poorly understood.

Manuka honey as a non-antibiotic alternative against Staphylococcus spp. and their small colony variant (SCVs) phenotypes.

The antibiotic resistance (ABR) crisis is an urgent global health priority. Staphylococci are among the problematic bacteria contributing to this emergency owing to their recalcitrance to many clinically important antibiotics. Staphylococcal pathogenesis is further complicated by the presence of small colony variants (SCVs), a bacterial subpopulation displaying atypical characteristics including retarded growth, prolific biofilm formation, heightened antibiotic tolerance, and enhanced intracellular persistence. These capabilities severely impede current chemotherapeutics, resulting in chronic infections, poor patient outcomes, and significant economic burden. Tackling ABR requires alternative measures beyond the conventional options that have dominated treatment regimens over the past 8 decades. Non-antibiotic therapies are gaining interest in this arena, including the use of honey, which despite having ancient therapeutic roots has now been reimagined as an alternative treatment beyond just traditional topical use, to include the treatment of an array of difficult-to-treat staphylococcal infections. This literature review focused on Manuka honey (MH) and its efficacy as an anti-staphylococcal treatment. We summarized the studies that have used this product and the technologies employed to study the antibacterial mechanisms that render MH a suitable agent for the management of problematic staphylococcal infections, including those involving staphylococcal SCVs. We also discussed the status of staphylococcal resistance development to MH and other factors that may impact its efficacy as an alternative therapy to help combat ABR.

The Neurodegenerative Disease Knowledge Portal: Propelling Discovery Through the Sharing of Neurodegenerative Disease Genomic Resources.

Although large-scale genetic association studies have proven opportunistic for the delineation of neurodegenerative disease processes, we still lack a full understanding of the pathological mechanisms of these diseases, resulting in few appropriate treatment options and diagnostic challenges. To mitigate these gaps, the Neurodegenerative Disease Knowledge Portal (NDKP) was created as an open-science initiative with the aim to aggregate, enable analysis, and display all available genomic datasets of neurodegenerative disease, while protecting the integrity and confidentiality of the underlying datasets. The portal contains 218 genomic datasets, including genotyping and sequencing studies, of individuals across ten different phenotypic groups, including neurological conditions such as Alzheimer's disease, amyotrophic lateral sclerosis, Lewy body dementia, and Parkinson's disease. In addition to securely hosting large genomic datasets, the NDKP provides accessible workflows and tools to effectively utilize the datasets and assist in the facilitation of customized genomic analyses. Here, we summarize the genomic datasets currently included within the portal, the bioinformatics processing of the datasets, and the variety of phenotypes captured. We also present example use-cases of the various user interfaces and integrated analytic tools to demonstrate their extensive utility in enabling the extraction of high-quality results at the source, for both genomics experts and those in other disciplines. Overall, the NDKP promotes open-science and collaboration, maximizing the potential for discovery from the large-scale datasets researchers and consortia are expending immense resources to produce and resulting in reproducible conclusions to improve diagnostic and therapeutic care for neurodegenerative disease patients.

Case Report, Multiple Giant Spiroadenocylindromas in a Geriatric Patient

Brooke-Spiegler Syndrome (BSS) is a rare autosomal dominant genodermatosis with variable penetrance, which is characterized by maintaining a progressive association of generally benign cutaneous adnexal neoformations among themselves. cylindromas, spiroadenomas and trichoepitheliomas. Other less frequently involved are trichoblastomas, follicular cysts, and organoid nevi. There are multiple phenotypic variants of SBS, which share the same genotypic origin; due to the overlap of the different lesions between them at a clinical, pathological, and genetic level, of which the present clinical case maintains a variant form that is rare in an association of multiple giant spiroadenocylindromas in a geriatric patient [1-11].

#1550 Incident hypertension: immune biomarkers and vascular phenotypes

Abstract Background and Aims Blood pressure (BP) regulation is mediated by cardiac, vascular, endocrine, renal, and immune system interactions. Hence, hypertension may exist as different phenotypic variants, with different clinical features and susceptibility to target organ damage. We aimed to analyse the circulating protein biomarker ‘signature’ of: 1) untreated hypertension; 2) hypertensive phenotypes identified by arterial and blood pressure parameters. Method 61 patients with hypertension, and 61 controls were assessed using 24hr ambulatory BP monitoring; endothelial function, arterial stiffness, carotid intima-media thickness (CIMT), and cardiovascular variability [1]. Circulating protein biomarkers analysed using Olink® Inflammation plasma biomarker panel, reported as NPX (Normalized Protein eXpression), in Log2 scale. Results 34 biomarkers dominated by cytokines and chemokines differed between normotensive and hypertensive subjects (Fig. 1), though failed to meet Bonferroni-adjusted threshold. Inflammatory biomarkers correlated with BP and arterial stiffness, BP variability, and CIMT, but not endothelial function. Associations were concordant across systolic and diastolic BP; TPP1, CCL7, CCL11, and CCL21 positively correlating; IL18R1, and KYNU negatively. These relationships were more pronounced in hypertensive subgroup, 85 biomarkers correlating including CD molecules (CD200R1, CD22, CD58, CD6, CD70) and cytokines (IL-5, IL-11, IL-15, IL-18, IL-32, IL-1RL2, IL-22RA1, IL-5RA). HGF, AGE, and CCL21 showed greatest between group differences and correlated with multiple BP or vascular parameters. Systolic nocturnal dipping demonstrated negative correlation with biomarkers relating to immune cell interactions and cellular adhesion (CTRC, EPHA1, LGALS4, SIT1, SMOC, IL-18 and TNFSF11). Machine learning techniques identified three phenotypes of hypertension, ‘arterially stiffened’, ‘vaso-protected’, and ‘non-dipper’ [1]. Sixteen of the 85 correlating biomarkers also differed between these phenotypic groups: Conclusion Hypertension is linked to alterations in circulating immune biomarkers. Multiple biomarkers correlated with both arterial stiffness and BP parameters. Some biomarkers are only correlated in the hypertensive group. Many also relate to nocturnal dipping, and differed across the hypertension endotypes. HGF is a promising biomarker for BP and arterial function; warranting further validation.

#3010 Characteristics of a Brazilian cohort with primary hyperoxaluria type 1 (PH1), an admixed population with different ethnic origins

Abstract Background and Aims Primary Hyperoxaluria type 1 (PH1) is caused by biallelic variants in the AGXT gene, leading to alanine:glyoxylate aminotransferase deficiency, hepatic overproduction of oxalate, hyperoxaluria, nephrolithiasis (NL), and/or nephrocalcinosis (NC), often progressing to chronic kidney disease (CKD) with variable phenotypes. Brazilian population is unique due to its diverse ancestry and high admixture rate, which makes this population an interesting group to expand clinical and genetic profile of PH1. Method A descriptive study of genetic confirmed PH1 patients from various regions of Brazil, involving demographic, clinical-laboratory, and genetic data. Results Twenty-one patients (17 families) were identified; 4 detected by family screening (2 with active disease). Parental consanguinity detected in 4 families (23.5%). Nineteen symptomatic patients (12 males) included. At PH1 diagnosis, 3 patients were on CKD stage 1, 1 on CKD 3 and 15 were on CKD 5. We observed notable clinical heterogeneity, and 3 groups are described according to the age at onset. Table 1 shows data for each group and symptomatic cases. All patients have received pyridoxine since PH1 diagnosis. Conclusion In this Brazilian cohort we observed a high percentage of patients diagnosed on CKD 5, detected by recurrence in the renal graft after isolated renal transplantation, and patients achieving CKD 5 after obstructive kidney stones episode. Several factors, including the broad phenotypic spectrum, the lack of awareness among physicians about the disease and the scarcity of diagnostic tools, may explain this delay in diagnosis. Therefore, there is a need to improve information to the Brazilian medical community. The genetic findings are similar to European and North America genetic descriptions and 2 novel variants were identified expanding the AGXT variants profile. However, it is noteworthy, the high percentage of compound heterozygous variants compared with other cohorts worldwide, which may be characteristic of an admixed population.

Synthetic aporphine alkaloids are potential therapeutics for Leigh syndrome

Mitochondrial diseases are mainly caused by dysfunction of mitochondrial respiratory chain complexes and have a variety of genetic variants or phenotypes. There are only a few approved treatments, and fundamental therapies are yet to be developed. Leigh syndrome (LS) is the most severe type of progressive encephalopathy. We previously reported that apomorphine, an anti- “off” agent for Parkinson’s disease, has cell-protective activity in patient-derived skin fibroblasts in addition to strong dopamine agonist effect. We obtained 26 apomorphine analogs, synthesized 20 apomorphine derivatives, and determined their anti-cell death effect, dopamine agonist activity, and effects on the mitochondrial function. We found three novel apomorphine derivatives with an active hydroxy group at position 11 of the aporphine framework, with a high anti-cell death effect without emetic dopamine agonist activity. These synthetic aporphine alkaloids are potent therapeutics for mitochondrial diseases without emetic side effects and have the potential to overcome the low bioavailability of apomorphine. Moreover, they have high anti-ferroptotic activity and therefore have potential as a therapeutic agent for diseases related to ferroptosis.

Etiological involvement of KCND1 variants in an X-linked neurodevelopmental disorder with variable expressivity

Utilizing trio whole-exome sequencing and a gene matching approach, we identified a cohort of 18 male individuals from 17 families with hemizygous variants in KCND1, including two de novo missense variants, three maternally inherited protein-truncating variants, and 12 maternally inherited missense variants. Affected subjects present with a neurodevelopmental disorder characterized by diverse neurological abnormalities, mostly delays in different developmental domains, but also distinct neuropsychiatric signs and epilepsy. Heterozygous carrier mothers are clinically unaffected. KCND1 encodes the α-subunit of Kv4.1 voltage-gated potassium channels. All variant-associated amino acid substitutions affect either the cytoplasmic N- or C-terminus of the channel protein except for two occurring in transmembrane segments 1 and 4. Kv4.1 channels were functionally characterized in the absence and presence of auxiliary β subunits. Variant-specific alterations of biophysical channel properties were diverse and varied in magnitude. Genetic data analysis in combination with our functional assessment shows that Kv4.1 channel dysfunction is involved in the pathogenesis of an X-linked neurodevelopmental disorder frequently associated with a variable neuropsychiatric clinical phenotype.