Mild Mutations Research Articles

Functional Analysis of Human GBA1 Missense Mutations in Drosophila: Insights into Gaucher Disease Pathogenesis and Phenotypic Consequences.

The human GBA1 gene encodes lysosomal acid β-glucocerebrosidase, whose activity is deficient in Gaucher disease (GD). In Drosophila, there are two GBA1 orthologs, Gba1a and Gba1b, and Gba1b is the bona fide GCase encoding gene. Several fly lines with different deletions in the Gba1b were studied in the past. However, since most GD-associated GBA1 mutations are point mutations, we created missense mutations homologous to the two most common GD mutations: the mild N370S mutation (D415S in Drosophila) and the severe L444P mutation (L494P in Drosophila), using the CRISPR-Cas9 technology. Flies homozygous for the D415S mutation (dubbed D370S hereafter) presented low GCase activity and substrate accumulation, which led to lysosomal defects, activation of the Unfolded Protein Response (UPR), inflammation/neuroinflammation, and neurodegeneration along with earlier death compared to control flies. Surprisingly, the L494P (called L444P hereafter) flies presented higher GCase activity with fewer lysosomal defects and milder disease in comparison to that presented by the D370S homozygous flies. Treatment with ambroxol had a limited effect on all homozygous fly lines tested. Overall, our results underscore the differences between the fly and human GCase enzymes, as evidenced by the distinct phenotypic outcomes of mutations in flies compared to those observed in human GD patients.

Progression, reliability, predicting parameters and sample size calculations for quantitative fundus autofluorescence measures in ABCA4-related retinopathy

Background/aimsTo investigate the progression of quantitative autofluorescence (qAF) measures and the potential as clinical trial endpoint in ABCA4-related retinopathy.MethodsIn this longitudinal monocentre study, 64 patients with ABCA4-related retinopathy (age (mean±SD),...

Variant-specific effects of GBA1 mutations on dopaminergic neuron proteostasis.

Glucocerebrosidase 1 (GBA1) mutations are the most important genetic risk factors for Parkinson's disease (PD). Clinically, mild (e.g., p.N370S) and severe (e.g., p.L444P and p.D409H) GBA1 mutations have different PD phenotypes, with differences in age at disease onset, progression, and the severity of motor and non-motor symptoms. We hypothesize that GBA1 mutations cause the accumulation of α-synuclein by affecting the cross-talk between cellular protein degradation mechanisms, leading to neurodegeneration. Accordingly, we tested whether mild and severe GBA1 mutations differentially affect the degradation of α-synuclein via the ubiquitin-proteasome system (UPS), chaperone-mediated autophagy (CMA), and macroautophagy and differentially cause accumulation and/or release of α-synuclein. Our results demonstrate that endoplasmic reticulum (ER) stress and total ubiquitination rates were significantly increased in cells with severe GBA1 mutations. CMA was found to be defective in induced pluripotent stem cell (iPSC)-derived dopaminergic neurons with mild GBA1 mutations, but not in those with severe GBA1 mutations. When examining macroautophagy, we observed reduced formation of autophagosomes in cells with the N370S and D409H GBA1 mutations and impairments in autophagosome-lysosome fusion in cells with the L444P GBA1 mutation. Accordingly, severe GBA1 mutations were found to trigger the accumulation and release of oligomeric α-synuclein in iPSC-derived dopaminergic neurons, primarily as a result of increased ER stress and defective macroautophagy, while mild GBA1 mutations affected CMA, which is mainly responsible for the degradation of the monomeric form of α-synuclein. Overall, our findings provide new insight into the molecular basis of the clinical variability in PD associated with different GBA1 mutations.

Genotype-Specific Cortisol Reserve in a Cohort of Subjects With Nonclassic Congenital Adrenal Hyperplasia (NCCAH).

Recent guidelines suggest that patients with nonclassic congenital adrenal hyperplasia (NCCAH) stop glucocorticoid therapy after achieving adult height. However, these guidelines do not differentiate between NCCAH genotype groups. Compare ACTH-stimulated cortisol and 17-hydroxyprogesterone (17OHP) levels, and the rate of partial cortisol insufficiency in subjects with NCCAH carrying one mild and one severe (mild/severe) mutation vs subjects with biallelic mild (mild/mild) mutations. Retrospective evaluation of the medical records of 122 patients who presented with postnatal virilization and were diagnosed with NCCAH. Patients underwent standard intravenous 0.25 mg/m2 ACTH stimulation testing. Those with stimulated 17OHP level ≥40 nmol/L were screened for the 9 most frequent CYP21A2 gene mutations followed by multiplex ligation-dependent probe amplification. A stimulated cortisol level below 500 nmol/L was defined as partial cortisol deficiency. Patients were subdivided into 3 genotype groups: 77 carried the mild/mild genotype, mainly homozygous for p.V281L mutation; 29 were compound heterozygous for mild/severe mutation, mainly p.V281L/p.I2Splice, and 16 were heterozygous for p.V281L, and were excluded from statistical evaluation. Stimulated cortisol levels were significantly lower in the mild/severe than in the mild/mild group (mean ± SD, 480 ± 90 vs 570 ± 125 nmol/L, P < .001). The mild/severe group exhibited a significantly higher rate of partial cortisol insufficiency (21/28, 75% vs 28/71, 39%, P = .004). Peak 17OHP was significantly higher in the mild/severe group (198 ± 92 vs 118 ± 50 nmol/L, P < .001). The high rate of partial adrenal insufficiency in the mild/severe group underscores the need to carefully consider the value of glucocorticoid therapy cessation and the importance of stress coverage in this group.

Ovarian reserve in women with cystic fibrosis: is this a cause of sub-fertility?

BackgroundOver the past two decades, increasing number of people with cystic fibrosis (CF) survive into adulthood. Compared to the general population, sub-fertility is an obstacle for many women with CF (wwCF). Decreased ovarian reserve has been proposed as a possible cause, but limited data is available to support this. The aim of this study was to evaluate the ovarian reserve in wwCF and to correlate this with patients’ demographic and clinical data.MethodsReproductive-aged wwCF were enrolled during their routine medical appointments. Assessment included Anti-Mullerian hormone (AMH) levels, routine blood tests and antral follicular count (AFC) evaluation. Additionally, demographic, and clinical information were collected.ResultsA total of wenty-three wwCF were enrolled, with ages ranging from 19 to 40 years (median 27 years). Among the fourteen wwCF who were considering pregnancy, five (35.7%) disclosed undergoing an infertility assessment and receiving fertility treatments. All but one patient had an Anti-Mullerian hormone (AMH) level between the 5th and 95th % for age. Measurement of the antral follicular count (AFC) was possible in 12 of the 23 patients and was ranging 8–40 with a median of 17. The proportion of wwCF presenting below median AMH values was not different in sub-fertile as compared to fertile wwCF (P value 0.54). There were no correlations between AMH levels and disease severity parameters. AMH seemed to be relatively higher in wwCF with mild class mutations, but this was not shown to have statistical significance.ConclusionsOur results, in contrast with the limited available published data, do not support the hypothesis that decreased ovarian reserve plays a major role in infertility in wwCF.

P-712 Transcriptomic Prediction of Spermatogenesis in the Ejaculates of Nonobstructive Azoospermic Men and Genomic Characterization of their Embryo Developmental Competence

Abstract Study question Can the genomic assessment of ejaculates from azoospermic men predict successful sperm extraction at testicular biopsy (TESE) and provide information on their reproductive potential? Summary answer RNAseq on the ejaculates of NOA men identified transcriptomic predictors of successful TESE outcome, while DNAseq evidenced gene-related mechanistics linked to reproductive performance. What is known already The most puzzling form of azoospermia is the testicular type. The chances of successful surgical sperm retrieval for these cases can be unpredictable, even when a benign histopathology has been obtained. The ability to identify individuals with complete loss of spermatogenesis at the seminiferous tubule level would help eliminate anesthesia and surgical risks, as well as financial and emotional distress. We propose to noninvasively assess the ejaculates from these men to predict successful TESE sperm retrieval. We utilize DNAseq to assess the impact of germline mutations on the embryo developmental competence of the surgically retrieved gametes. Study design, size, duration Over 4 years, we recruited men with normal peripheral karyotypes and azoospermia (n = 23), confirmed by absence of spermatozoa in extensive semen analyses. We performed epigenetic assessments on their ejaculates to compare transcriptomic profiles according to whether spermatozoa were successfully retrieved after TESE ((+)Sperm,n=11), or not ((-)Sperm,n=12). We then performed DNAseq (IRB 1006101085) on the testicular spermatozoa retrieved, to assess their ability to generate a pregnancy (fertile) or not (infertile), while controlling for maternal age. Participants/materials, setting, methods RNA was isolated from seminal fluid for epigenetic assessment (21,855 genes). A &amp;gt; 1 absolute log2fold change and P&amp;lt;0.0005 were considered significant. Transcriptomic profiles were compared between the (-)Sperm and (+)Sperm cohorts. For genetic assessment, surgically retrieved spermatozoal DNA from the (+)Sperm and obstructive azoospermic (OA) control (n = 19) cohorts were extracted and amplified. Gene mutation profiles, detected by CLC Genomic Server 9.0, were assessed for the (+)Sperm cohort according to ICSI outcomes, compared to the OA-control. Main results and the role of chance Transcriptomic analyses on seminal plasma from the 23 NOA men identified 8 imbalanced genes, involved in spermatogenesis (TMCO5B,C10orf62,SMKR1,SPZ1), sperm function (NEU1,TPTE2), and testis development (TRPC1,IGSF11-AS1). TPTE2 was almost completely expressed in 81.8%(9/11) of the (+)Sperm cohort (paternal age, 37.1±6yrs), while IGSF11-AS1 was underexpressed in all 12 (-)Sperm men (paternal age, 34.3±5yrs). Both genes are implicated in spermatogenic defects and are normally highly expressed in testis. Interestingly, NEU1, localized on the sperm acrosome and crucial for sperm capacitation, was exclusively underexpressed in (-)Sperm while overexpressed in (+)Sperm cohorts. Genomic analyses of spermatozoal DNA from the (+)Sperm cohort was compared to a matched control of OA patients (paternal age, 36.8±7yrs). Spermatozoa from the study cohort displayed mutations on genes involved in RNA transcription (POLR2L), apoptosis (AP5M1), and spermiogenic functions (AP1S2,AP1G2,APOE), while these genes were unaffected in the OA-control. When we compared sperm genetic profiles of the successful TESE cohort (maternal age, 36.8±2yrs, paternal age, 37.1±6yrs) according to ICSI outcome, we found that spermatozoa from the 8 fertile patients, all with term pregnancies, displayed consistent mild mutations on MPIG6B (stem cell lineage differentiation) while gametes from their 3 infertile counterparts carried severe mutations on genes (MBD5,CCAR1,PMEPA1,POLK,REC8,REPIN1,MAPRE3,ARL4C) involved in early embryonic development, and therefore failed to achieve embryo implantation. Limitations, reasons for caution Although we predicted, by transcriptomic analyses of ejaculates from NOA men, the presence of spermatozoa and characterized their embryo developmental competence through genetic profiling, these preliminary results need validation in a larger study cohort. Moreover, although controlled for, a confounding female factor cannot be undoubtfully excluded. Wider implications of the findings Epigenetic assessment of seminal fluid from NOA men can noninvasively identify biomarkers capable of predicting complete loss of spermatogenesis, sparing these patients from unnecessary surgery. Gene profiling can identify gametes capable of supporting term pregnancies, laying the groundwork for precision medicine in male infertility screening. Trial registration number n/a

Only one beer can be mortal: a case report of two sisters with cardiac arrest due to a homozygous mutation in PPA2 gene

We report the long way to the correct diagnosis in two teenage sisters who developed a cardiac arrest after consuming minimal amounts of alcohol. The older girl dramatically survived two cardiac arrests at the age of 14 and 15 years. She underwent an extensive examination that revealed isolated cardiac abnormalities including fibrosis, dilated cardiomyopathy and inflammation. The younger girl also had a cardiac arrest at the age of 15 and died suddenly after consuming 1–2 beers, 3 years after her sister´s first incident. Autopsy of the heart revealed acute myocarditis without structural alterations. Multigene panel analysis (not including PPA2) showed SCN5A and CACNA1D variants in both sisters and their healthy mother. Six years later duo exome allowed the diagnosis of an autosomal recessive PPA2-related mitochondriopathy. We discuss the molecular results and clinical picture of our patients compared to other PPA2-related cases. We highlight the diagnostic contribution of multigene panels and exome analysis. The genetic diagnosis is important for medical care and for everyday life, specifically because alcohol intake can result in cardiac arrest and should be strictly avoided. Conclusion: Duo exome sequencing clarified the diagnosis of PPA2-related mitochondriopathy in two sisters with isolated cardiac features and sudden cardiac arrest triggered by minimal amounts of alcohol.What is Known:• Multigene-Panel or exome analysis is a valuable tool to identify genetic causes of hereditary cardiac arrhythmias.• Variants of unknown significance can lead to misinterpretation. PPA2-related mitochondriopathy is a very rare autosomal recessive condition that is normally fatal in infancy.What is New:• Duo exome analysis in two teeenage sisters with cardiac arrest revealed a homozygous mild PPA2 mutation as the underlying pathology restricted to the heart muscle

Abstract A026: Stochastic phenotypes in RAS-dependent developmental diseases

Abstract Germline mutations upregulating RAS signaling are associated with multiple developmental disorders. A hallmark of these conditions is that the same mutation may present vastly different phenotypes in different individuals, even in monozygotic twins. We demonstrate how the origins of such largely unexplained phenotypic variations may be dissected using highly controlled studies in Drosophila that have been gene edited to carry activating variants of MEK, a core enzyme in the RAS pathway. This allowed us to measure the small but consistent increase in signaling output of such alleles in vivo. The fraction of mutation carriers reaching adulthood was strongly reduced, but most surviving animals had normal RAS-dependent structures. We rationalize these results using a stochastic signaling model and support it by quantifying cell fate specification errors in bilaterally symmetric larval trachea, a RAS-dependent structure that allows us to isolate the effects of mutations from potential contributions of genetic modifiers and environmental differences. We propose that the small increase in signaling output shifts the distribution of phenotypes into a regime, where stochastic variation causes defects in some individuals, but not in others. Our findings shed light on phenotypic heterogeneity of developmental disorders caused by deregulated RAS signaling and offer a framework for investigating causal effects of other pathogenic alleles and mild mutations. Citation Format: Robert A. Marmion, Alison G. Simpkins, Lena A. Barrett, Jodi Schottenfeld-Roames, Trudi Schüpbach, Stanislav Y. Shvartsman. Stochastic phenotypes in RAS-dependent developmental diseases [abstract]. In: Proceedings of the AACR Special Conference: Targeting RAS; 2023 Mar 5-8; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Res 2023;21(5_Suppl):Abstract nr A026.

SMPD1 expression profile and mutation landscape help decipher genotype–phenotype association and precision diagnosis for acid sphingomyelinase deficiency

BackgroundAcid sphingomyelinase deficiency (ASMD) disorder, also known as Niemann–Pick disease (NPD) is a rare genetic disease caused by mutations in SMPD1 gene, which encodes sphingomyelin phosphodiesterase (ASM). Except for liver and spleen enlargement and lung disease, two subtypes (Type A and B) of NDP have different onset times, survival times, ASM activities, and neurological abnormalities. To comprehensively explore NPD’s genotype-phenotype association and pathophysiological characteristics, we collected 144 NPD cases with strict quality control through literature mining.ResultsThe difference in ASM activity can differentiate NPD type A from other subtypes, with the ratio of ASM activity to the reference values being lower in type A (threshold 0.045 (4.45%)). Severe variations, such as deletion and insertion, can cause complete loss of ASM function, leading to type A, whereas relatively mild missense mutations generally result in type B. Among reported mutations, the p.Arg3AlafsX76 mutation is highly prevalent in the Chinese population, and the p.R608del mutation is common in Mediterranean countries. The expression profiles of SMPD1 from GTEx and single-cell RNA sequencing data of multiple fetal tissues showed that high expressions of SMPD1 can be observed in the liver, spleen, and brain tissues of adults and hepatoblasts, hematopoietic stem cells, STC2_TLX1-positive cells, mesothelial cells of the spleen, vascular endothelial cells of the cerebellum and the cerebrum of fetuses, indicating that SMPD1 dysfunction is highly likely to have a significant effect on the function of those cell types during development and the clinicians need pay attention to these organs or tissues as well during diagnosis. In addition, we also predicted 21 new pathogenic mutations in the SMPD1 gene that potentially cause the NPD, signifying that more rare cases will be detected with those mutations in SMPD1. Finally, we also analysed the function of the NPD type A cells following the extracellular milieu.ConclusionsOur study is the first to elucidate the effects of SMPD1 mutation on cell types and at the tissue level, which provides new insights into the genotype-phenotype association and can help in the precise diagnosis of NPD.

The HFE p.H63D (p.His63Asp) Polymorphism Is a Modifier of ALS Outcome in Italian and French Patients with SOD1 Mutations

Background: Data from published studies about the effect of HFE polymorphisms on ALS risk, phenotype, and survival are still inconclusive. We aimed at evaluating whether the p.H63D polymorphism is a modifier of phenotype and survival in SOD1-mutated patients. Methods: We included 183 SOD1-mutated ALS patients. Mutations were classified as severe or mild according to the median survival of the study population. Patients were screened for the HFE p.H63D polymorphism. Survival was calculated using the Kaplan-Meier modeling, and differences were measured by the log-rank test. Multivariable analysis was performed with the Cox proportional hazards model (stepwise backward). Results: SOD1 severe mutation carriers show more frequent familial history for ALS and shorter survival compared to mild mutation carriers. Carriers and non-carriers of the p.H63D polymorphism did not differ in terms of sex ratio, frequency of positive familial history, age at onset, and bulbar/spinal ratio. In univariate and in Cox multivariable analysis using sex, age at onset, site of onset, family history, country of origin, and mutation severity as covariates, p.H63D carriers had a longer survival (p = 0.034 and p = 0.004). Conclusions: We found that SOD1-mutated ALS patients carrying the p.H63D HFE polymorphism have a longer survival compared to non-carriers, independently of sex, age and site of onset, family history, nation of origin, and severity of mutations, suggesting a possible role as disease progression modifier for the p.H63D HFE polymorphism in SOD1-ALS.

Stochastic phenotypes in RAS-dependent developmental diseases

Germline mutations upregulating RAS signaling are associated with multiple developmental disorders. A hallmark of these conditions is that the same mutation may present vastly different phenotypes in different individuals, even in monozygotic twins. Here, we demonstrate how the origins of such largely unexplained phenotypic variations may be dissected using highly controlled studies in Drosophila that have been gene edited to carry activating variants of MEK, a core enzyme in the RAS pathway. This allowed us to measure the small but consistent increase in signaling output of such alleles invivo. The fraction of mutation carriers reaching adulthood was strongly reduced, but most surviving animals had normal RAS-dependent structures. We rationalize these results using a stochastic signaling model and support it by quantifying cell fate specification errors in bilaterally symmetric larval trachea, a RAS-dependent structure that allows us to isolate the effects of mutations from potential contributions of genetic modifiers and environmental differences. We propose that the small increase in signaling output shifts the distribution of phenotypes into a regime, where stochastic variation causes defects in some individuals, but not in others. Our findings shed light on phenotypic heterogeneity of developmental disorders caused by deregulated RAS signaling and offer a framework for investigating causal effects of other pathogenic alleles and mild mutations in general.

Genotype-phenotype relationships of truncating mutations, p.E297G and p.D482G in bile salt export pump deficiency

Bile salt export pump (BSEP) deficiency frequently necessitates liver transplantation in childhood. In contrast to two predicted protein truncating mutations (PPTMs), homozygous p.D482G or p.E297G mutations are associated with relatively mild phenotypes, responsive to surgical interruption of the enterohepatic circulation (siEHC). The phenotype of patients with a compound heterozygous genotype of one p.D482G or p.E297G mutation and one PPTM has remained unclear. We aimed to assess their genotype-phenotype relationship. From the NAPPED database, we selected patients with homozygous p.D482G or p.E297G mutations (BSEP1/1; n= 31), with one p.D482G or p.E297G, and one PPTM (BSEP1/3; n= 30), and with two PPTMs (BSEP3/3; n= 77). We compared clinical presentation, native liver survival (NLS), and the effect of siEHC on NLS. The groups had a similar median age at presentation (0.7-1.3 years). Overall NLS at age 10 years was 21% in BSEP1/3 vs. 75% in BSEP1/1 and 23% in BSEP3/3 (p <0.001). Without siEHC, NLS in the BSEP1/3 group was similar to that in BSEP3/3, but considerably lower than in BSEP1/1 (at age 10 years: 38%, 30%, and 71%, respectively; p= 0.003). After siEHC, BSEP1/3 and BSEP3/3 were associated with similarly low NLS, while NLS was much higher in BSEP1/1 (10 years after siEHC, 27%, 14%, and 92%, respectively; p <0.001). Individuals with BSEP deficiency with one p.E297G or p.D482G mutation and one PPTM have a similarly severe disease course and low responsiveness to siEHC as those with two PPTMs. This identifies a considerable subgroup of patients who are unlikely to benefit from interruption of the enterohepatic circulation by either surgical or ileal bile acid transporter inhibitor treatment. This manuscript defines the clinical features and prognosis of individuals with BSEP deficiency involving the combination of one relatively mild and one very severe BSEP deficiency mutation. Until now, it had always been assumed that the mild mutation would be enough to ensure a relatively good prognosis. However, our manuscript shows that the prognosis of these patients is just as poor as that of patients with two severe mutations. They do not respond to biliary diversion surgery and will likely not respond to the new IBAT (ileal bile acid transporter) inhibitors, which have recently been approved for use in BSEP deficiency.

Treating early postnatal circuit defect delays Huntington's disease onset and pathology in mice.

Recent evidence has shown that even mild mutations in the Huntingtin gene that are associated with late-onset Huntington's disease (HD) disrupt various aspects of human neurodevelopment. To determine whether these seemingly subtle early defects affect adult neural function, we investigated neural circuit physiology in newborn HD mice. During the first postnatal week, HD mice have less cortical layer 2/3 excitatory synaptic activity than wild-type mice, express fewer glutamatergic receptors, and show sensorimotor deficits. The circuit self-normalizes in the second postnatal week but the mice nonetheless develop HD. Pharmacologically enhancing glutamatergic transmission during the neonatal period, however, rescues these deficits and preserves sensorimotor function, cognition, and spine and synapse density as well as brain region volume in HD adult mice.

Markov State Models and Molecular Dynamics Simulations Reveal the Conformational Transition of the Intrinsically Disordered Hypervariable Region of K-Ras4B to the Ordered Conformation.

K-Ras4B, the most frequently mutated Ras isoform in human tumors, plays a vital part in cell growth, differentiation, and survival. Its tail, the C-terminal hypervariable region (HVR), is involved in anchoring K-Ras4B at the cellular plasma membrane and in isoform-specific protein-protein interactions and signaling. In the inactive guanosine diphosphate-bound state, the intrinsically disordered HVR interacts with the catalytic domain at the effector-binding region, rendering K-Ras4B in its autoinhibited state. Activation releases the HVR from the catalytic domain, with its ensemble favoring an ordered α-helical structure. The large-scale conformational transition of the HVR from the intrinsically disordered to the ordered conformation remains poorly understood. Here, we deploy a computational scheme that integrates a transition path-generation algorithm, extensive molecular dynamics simulation, and Markov state model analysis to investigate the conformational landscape of the HVR transition pathway. Our findings reveal a stepwise pathway for the HVR transition and uncover several key conformational substates along the transition pathway. Importantly, key interactions between the HVR and the catalytic domain are unraveled, highlighting the pathogenesis of K-Ras4B mild mutations in several congenital developmental anomaly syndromes. Together, these findings provide a deeper understanding of the HVR transition mechanism and the regulation of K-Ras4B activity at an atomic level.

Mutational Spectrum of the CFTR Gene in the Kazakhstan Population

To study the frequency and spectrum of CFTR gene variants in different ethnic groups of Kazakhstan. We reviewed the records of 58 patients with cystic fibrosis. All the patients underwent molecular genetic analysis to reveal genotype-phenotype correlations. The median (IQR) age of the patients was 5.4 year (7 months, 18 year); 40% were diagnosed at the age of 5-10 year. The study identified 28 specific variants: p.Phe508del, the variant most common in the European population, was detected in 30 patients (51.7%). Variants other than p.Phe508del were revealed in 31% (21 patients). We found a number of specific variants characteristic of the Kazakhstani population. A pronounced regression of disease symptoms was detected in patients with mild mutations; whereas in patients with severe mutations, therapy produced very little effect.

Bartter Syndrome in a Child With Solitary Functioning Kidney

Bartter Syndrome (BS) is a hereditary condition characterized by polyuria, renal salt wasting, and hypokalemic metabolic alkalosis with high serum renin and aldosterone levels. Patients with BS usually have symptoms in the first two years of life, but they might also be diagnosed at school age or later. Associations between congenital renal and urinary system anomalies and BS are extremely rare. Here we present a case of a 4-year-old girl having a solitary functioning kidney (SFK) due to right renal agenesis, who eventually diagnosed as BS in the light of clinical and laboratory findings. The patient applied to the pediatric nephrology department with the complaint of polyuria. Laboratory evaluation revealed hyponatremia, hypochloremia, hypokalemia with metabolic alkalosis, and high renin and aldosterone levels. Urine sodium, chloride, potassium excretions were increased. Sweat test was normal. CLCNKB mutation with the diagnosis of classic BS was negative. We assume that our patient might have another type of BS with a milder mutation. Urinary anomalies accompanying BS are very rarely reported and up to our knowledge the togetherness of renal agenesis and BS has not been defined in the literature yet.

Dissection and Direct Imaging of Axonal Transport in Drosophila Segmental Nerves.

For neurons, especially those with long axons, the forceful transport of mitochondria, vesicles, and other cytoplasmic components by cytoskeletal motors is vital. Defects in cytoplasmic transport machinery cause a degradation of signaling capacity that is most severe for neurons with the longest axons. In humans, with motor axons up to a meter long, even a mild mutation in one copy of the gene that codes for kinesin-1, the primary anterograde axonal transport motor, can cause spastic paraplegia and other distal neuropathies.To address questions about the molecular mechanisms of organelle movement, we turned to Drosophila as a model system, because it offered rigorous genetic and molecular approaches to the identification and inhibition of specific elements of transport machinery. However, methods for direct observation of organelle transport were largely lacking. We describe here an approach that we developed for imaging the transport behaviors of specific organelles in the long motor axons of larvae. It is straightforward, the equipment is commonly available, and it provides a powerful tool for studying the contributions of specific proteins to organelle transport mechanisms.

A Paradigm shift in genotype-phenotype relationships in β-thalassaemia.

A Paradigm shift in genotype-phenotype relationships in β-thalassaemia.

Clinical and instrumental characterization of GBA-related Parkinson's disease: Focus on cardiovascular and sudomotor autonomic dysfunction and other non-motor features. Does the type of mutation matter?

Some non-motor features (e.g. dementia) present more frequently in glucocerebrosidase-associated Parkinson's Disease (GBA-PD). What is the autonomic profile in GBA-PD compared to PD non-carriers (iPD)? Is there any difference between carriers of severe (GBA-SM) vs. mild (GBA-MM) mutations?

Acute Pancreatitis in a Previously Exocrine Pancreatic Insufficient Cystic Fibrosis Patient Who Had Improved Pancreatic Function After Being Treated With Lumacaftor/Ivacaftor

Exocrine pancreatic insufficiency (EPI) is a common complication of cystic fibrosis (CF). While previously considered to be irreversible, recent reported cases document improved pancreatic function in CF patients with mild mutations after ivacaftor treatment alone. We report a 12-year-old female with homozygous F508del CF and EPI who developed acute pancreatitis after 3 years on lumacaftor/ivacaftor and subsequently had improved pancreatic function. As CF therapies advance, some EPI CF patients with more severe CF transmembrane conductance regulator mutations may see improved pancreatic function and subsequently develop pancreatitis.