PTPA variants and impaired PP2A activity in early-onset parkinsonism with intellectual disability.

The protein phosphatase 2A complex (PP2A), the major Ser/Thr phosphatase in the brain, is involved in a number of signalling pathways and functions, including the regulation of crucial proteins for neurodegeneration, such as alpha-synuclein, tau and LRRK2. Here, we report the identification of variants in the PTPA/PPP2R4 gene, encoding a major PP2A activator, in two families with early-onset parkinsonism and intellectual disability. We carried out clinical studies and genetic analyses, including genome-wide linkage analysis, whole-exome sequencing, and Sanger sequencing of candidate variants. We next performed functional studies on the disease-associated variants in cultured cells and knock-down of ptpa in Drosophila melanogaster. We first identified a homozygous PTPA variant, c.893T>G (p.Met298Arg), in patients from a South African family with early-onset parkinsonism and intellectual disability. Screening of a large series of additional families yielded a second homozygous variant, c.512C>A (p.Ala171Asp), in a Libyan family with a similar phenotype. Both variants co-segregate with disease in the respective families. The affected subjects display juvenile-onset parkinsonism and intellectual disability. The motor symptoms were responsive to treatment with levodopa and deep brain stimulation of the subthalamic nucleus. In overexpression studies, both the PTPA p.Ala171Asp and p.Met298Arg variants were associated with decreased PTPA RNA stability and decreased PTPA protein levels; the p.Ala171Asp variant additionally displayed decreased PTPA protein stability. Crucially, expression of both variants was associated with decreased PP2A complex levels and impaired PP2A phosphatase activation. PTPA orthologue knock-down in Drosophila neurons induced a significant impairment of locomotion in the climbing test. This defect was age-dependent and fully reversed by L-DOPA treatment. We conclude that bi-allelic missense PTPA variants associated with impaired activation of the PP2A phosphatase cause autosomal recessive early-onset parkinsonism with intellectual disability. Our findings might also provide new insights for understanding the role of the PP2A complex in the pathogenesis of more common forms of neurodegeneration.

Guillain-Barré syndrome following the first dose of Pfizer-BioNTech COVID-19 vaccine: case report and review of reported cases.

BACKGROUND: Since the SARS-CoV-2 pandemic has started in December 2019, millions of people have been infected all over the world. Vaccination is the most efficient tool to end this pandemic, but vaccine surveillance is necessary to identify side effects. Some studies have shown that neurological complications after COVID-19 vaccination are rare and dominated by demyelinating disease. CASE PRESENTATION: We present a case of a 67-year-old man who presented 7 days following his first dose of Pfizer-BioNTech COVID-19 vaccine a rapidly progressive ascending muscle weakness. The diagnosis of Guillain-Barré syndrome (GBS) was confirmed according to the clinical features, the albumino-cytological dissociation in the cerebrospinal fluid, and the electroneuromyography findings. The workup for all known infections associated with immune-mediated GBS was negative. The patient received treatment with intravenous immunoglobulin. Neurological examination 1 month after discharge showed full recovery and he regained his baseline functional status. CONCLUSIONS: As far as we know, this is the first reported case in Tunisia. Although extremely rare, neurologists should remain vigilant for acute inflammatory demyelinating polyradiculoneuropathy after COVID-19 vaccination.

LRRK2 G2019S Parkinson's disease with more benign phenotype than idiopathic.

OBJECTIVES: The LRRK2-G2019S mutation is the most common cause of Parkinson's disease (PD) in North Africa. G2019S-PD has been described as similar to idiopathic with minor clinical differences. The aim of this study was to determine the G2019S-related phenotype and to investigate gender and gene dosage effects on clinical features of G2019S carriers. PATIENTS AND METHODS: The G2019S mutation was screened in 250 Tunisian patients with PD. Twenty-four patients carrying mutations in other PD genes were excluded. Logistic regression models were used to compare clinical features between the studied groups. RESULTS: G2019S carriers (107 cases) and non-carriers (119 cases) were similar in disease duration, levodopa doses, and gender and phenotype distributions. However, carriers had a younger age at examination, higher level of education, and were more likely to report family history of PD and to develop PD at earlier age (P = 0.017). Adjusted for age, sex, disease duration, levodopa-equivalent dose and educational level, MMSE scores remained significantly higher (adjust P = 0.019) and UPDRS-III scores were lower (adjust P = 0.012) in the G2019S carriers than non-carriers. Demographic characteristics of men and women with G2019S mutation were similar, but men had higher level of education, better cognition (adjust P-value for educational level = 0.042) and less tendency towards depression than females (adjust P = 0.046). Furthermore, PD phenotype did not differ between the homozygous and heterozygous G2019S carriers. CONCLUSION: In this study, G2019S carriers had a more benign phenotype than non-carriers. Cognitive impairment and depression were less common in G2019S male carriers compared with females. In addition, we found that LRRK2 gene dosage does not influence the severity of PD.

Using KASP technique to screen LRRK2 G2019S mutation in a large Tunisian cohort.

BACKGROUND: In North African populations, G2019S mutation in LRRK2 gene, encoding for the leucine-rich repeat kinase 2, is the most prevalent mutation linked to familial and sporadic Parkinson's disease (PD). Early detection of G2019S by fast genetic testing is very important to guide PD's diagnosis and support patients and their family caregivers for better management of their life according to disease's evolution. METHODS: In our study, a genetic PD's diagnosis tool was developed for large scale genotyping using Kompetitive Allele Specific PCR (KASP) technology. We investigated G2019S's frequency in 250 Tunisian PD patients and 218 controls. RESULTS: We found that 33.6% of patients and 1.3% of controls were carriers. Demographic characteristics of patients with G2019S had no differences compared with non-carrier patients. Thereby, we could emphasize the implication of G2019S in PD without any distinctive demographic factors in the studied cohort. Sixty patients out of 250 were genotyped using Taqman assay and Sanger sequencing. The genotyping results were found to be concordant with KASP assay. CONCLUSIONS: The G2019S mutation frequency in our cohort was similar to that reported in previous studies. Comparing to Taqman assay and Sanger sequencing, KASP was shown to be a reliable, time and cost effective genotyping assay for routine G2019S screening in genetic testing laboratories.

Acute-onset chronic inflammatory demyelinating polyneuropathy following AstraZeneca COVID-19 vaccine: a case report.

COVID-19 vaccination side effects have been increasingly reported, including new-onset autoimmune diseases such as chronic arthritis, thrombocytopenia, Guillain-Barré syndrome (GBS), and more recently chronic inflammatory demyelinating polyneuropathies (CIDP). Molecular mimicry and vaccine adjuvants appear to be important contributors to immune-mediated neuropathies. However, whether the link between the COVID-19 vaccine and these autoimmune disorders is coincidental or causal remains uncertain. We describe the ever-reported case of acute-onset CIDP following the Oxford/AstraZeneca vaccine in Tunisia. The patient is a 41-year-old man who presented with acute, worsening weakness of the four limbs. The symptoms appeared 15 days after his first dose of the AstraZeneca vaccine. The diagnosis of GBS was initially confirmed according to the clinical features, the albumino-cytological dissociation in the cerebrospinal fluid (CSF), and the electroneuromyography (ENMG) findings. Serum workup for all known infections associated with immune-mediated neuropathy was negative. The patient was treated with plasma exchange without initial improvement followed by aggravation of the symptomatology after an interval of four and a half months. Control ENMG showed signs of CIDP meeting the European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) criteria of 2021. The patient was treated with maintenance intravenous immunoglobulin and oral corticosteroids. Neurological examination 3 months after discharge showed partial improvement. Worldwide, cases of demyelinating polyneuropathies post-COVID-19 vaccination are increasingly reported. The acute onset of CIDP might lead to a misdiagnosis of GBS. Awareness of this complication and distinction from GBS enables early relay with maintenance treatment to prevent relapses and severe complications. Post-COVID neuropathies are found to be more frequently linked to the AstraZeneca vaccine, however, temporal association does not confirm causal association.

Effects of a nighttime melatonin ingestion on dynamic postural balance and muscle strength the following morning in people living with multiple sclerosis: A preliminary study.

BACKGROUND: Decreased endogenous melatonin concentrations in people with multiple sclerosis (PwMS) are associated with fatigue and pain that impair postural balance and muscle strength. Melatonin ingestion had analgesic and anti-fatigue effects. However, the acute effect of exogenous melatonin on dynamic postural stability and muscle strength has not been studied yet in PwMS. This study aimed to investigate the safety and the efficacy of a nighttime melatonin intake on dynamic postural balance and lower-extremity muscle strength the following morning in PwMS. METHODS: Fourteen PwMS (28.36 ± 6.81 years) were assessed (8 a.m.) pre- and post-acute intake of melatonin or placebo (6mg, 30 minutes before nocturnal bedtime). Evaluated parameters included dynamic postural balance (force platform), lower-extremity muscle strength [Five-Repetition Sit-To-Stand Test (5-STST)], hand dexterity (Nine-Hole Peg Test), nociceptive pain [Visual Analogue Scale (VAS)], neuropathic pain [Neuropathic Pain 4 Questions (DN4)], sleep quality and fatigue perception [Hooper Index (HI)]. RESULTS: In the frontal plane, melatonin reduced the center of pressure (CoP) path length (CoPL), CoPL in the anteroposterior axis (CoPLY) and CoP sway area (CoPAr) compared with placebo by 7.56% (p=0.02, Cohens'd (d)=1.24), 19.27% (p<0.001, d=2.60) and 13.82% (p<0.001, d=2.02), respectively. Melatonin induced a higher decrease in these posturographic parameters compared with placebo in the sagittal plane [CoPL: 9.10% (p=0.005, d=1.02), CoPLY: 4.29% (p=0.025, d=1.07) and CoPAr: 7.45% (p=0.038, d=0.74)]. Melatonin decreased 5-STST duration as well as VAS, DN4, HI-fatigue and HI-sleep scores compared with placebo by 8.19% (p=0.008, d=1.19), 5.74% (p=0.04, d=0.82), 27.30% (p=0.023, d=0.98), 40.15% (p=0.044, d=0.85) and 30.16% (p=0.012, d=1.10), respectively. CONCLUSION: This preliminary study, among PwMS, showed that acute melatonin ingestion was safe and efficient for improving dynamic postural stability and lower-extremity muscle strength probably through its analgesic and anti-fatigue effects.

Ischemic Stroke in Young Tunisian Adults.

INTRODUCTION: Ischemic Stroke in young adults is a real public health problem; it's a major cause of disability, alters quality of life and has a great socio-economic impact. AIM: determine risk factors and specify the etiology of arterial ischemic stroke in young Tunisian adults. METHODS: In this 5 years retrospective study (2015-2020), we included all young adults (18-50 years) admitted for arterial ischemic stroke (AIS). Risk factors were registered and analyzed. All patients were investigated using a standard protocol: biological tests, brain imaging, carotid ultrasound and cardiac assessment. Additional investigations were carried out at the discretion of the treating physician. The cause of ischemic stroke was classified according to the TOAST criteria. RESULTS: We collected 200 patients with AIS. The mean age was 41.37 years ± 6.99. Traditional vascular risk factors were observed in more than 1/4 patients. A definite cause of stroke was identified in 120 patients. Cardio-embolic causes were the most common among our patients (19%) followed by atherosclerosis of the large arteries (11.5%). Other determined etiologies were found in 27.5% of patients. The etiology remained unclear in 40% of cases: undetermined despite complete investigation in 17.5%, undetermined and incompletely investigated 14.5 % and more than one potential pathomechanisms in 8%. CONCLUSION: Through this study, we demonstrated the diversity of etiology of stroke in young Tunisian adults. Changes of lifestyle are responsible for the occurrence of the traditional risk factors at an early age. Rheumatic heart diseases remain a frequent cause of AIS in our area.

12-week melatonin supplementation improved dynamic postural stability and walking performance in persons living with multiple sclerosis: A randomized controlled trial.

BACKGROUND: Persons with multiple sclerosis (PwMS) suffer from sleep disturbances, fatigue and pain, which can be due, at least in part, to decreased levels of endogenous melatonin. These alterations could exacerbate postural instability, gait disorders and fall risk. Acute effects of exogenous melatonin on physical disorders have been studied in PwMS but its long-term effects on these parameters have not been explored yet in this population. This study aimed to determine the impact of chronic melatonin intake on dynamic postural stability, walking performance and fall risk in PwMS. METHODS: This randomized placebo-controlled study included 27 PwMS who were assigned to either melatonin group (MG, n=15) or placebo group (PG, n=12) (3 mg/night for 12 weeks). Dynamic postural balance (force platform), walking performance (locometer) and fall risk (Four Square Step Test) were evaluated pre (T0)- and post (T1)-intervention. Sleep quality (Pittsburgh Sleep Quality Index (PSQI)), fatigue perception (Fatigue Severity Scale (FSS)), neuropathic pain (Neuropathic Pain Questionnaire 4 (DN4)) and quality of life (International Multiple Sclerosis (MS) Quality of Life Questionnaire) were also assessed at T0 and T1. RESULTS: The center of pressure mean velocity decreased in MG compared with PG in the frontal plane (22.98 %, p=0.028). Stride length and walking speed increased in MG comparatively with PG (18.09 %, p=0.036; 9.65 %, p=0.025, respectively). The PSQI (55.89 %, p<0.001), FSS (32.38 %, p=0.003) and DN4 (32.41 %, p=0.035) scores decreased in MG compared with PG. CONCLUSION: 12-week melatonin supplementation can be recommended for managing MS-related gait disorders and dynamic postural imbalance. This therapy may also be prescribed for PwMS due to its anti-fatigue and analgesic effects as well as its benefits on sleep quality. CLINICAL REGISTRATION: This study was prospectively recorded in the Pan African Clinical Trial Registry database (PACTR202007465309582) (https://pactr.samrc.ac.za/.).

Analysis of Fuel Alternative Products Obtained by the Pyrolysis of Diverse Types of Plastic Materials Isolated from a Dumpsite Origin in Pakistan.

The current energy crisis and waste management problems have compelled people to find alternatives to conventional non-renewable fuels and utilize waste to recover energy. Pyrolysis of plastics, which make up a considerable portion of municipal and industrial waste, has emerged as a feasible resolution to both satisfy our energy needs and mitigate the issue of plastic waste. This study was therefore conducted to find a solution for plastic waste management problems, as well as to find an alternative to mitigate the current energy crisis. Pyrolysis of five of the most commonly used plastics, polyethylene terephthalate (PET), high- and low-density polyethylene (HDPE, LDPE), polypropylene (PP), and polystyrene (PS), was executed in a pyrolytic reactor designed utilizing a cylindrical shaped stainless steel container with pressure and temperature gauges and a condenser to cool down the hydrocarbons produced. The liquid products collected were highly flammable and their chemical properties revealed them as fuel alternatives. Among them, the highest yield of fuel conversion (82%) was observed for HDPE followed by PP, PS, LDPE, PS, and PET (61.8%, 58.0%, 50.0%, and 11.0%, respectively). The calorific values of the products, 46.2, 46.2, 45.9, 42.8 and 42.4 MJ/kg for LPDE, PP, HPDE, PS, and PET, respectively, were comparable to those of diesel and gasoline. Spectroscopic and chromatographic analysis proved the presence of alkanes and alkenes with carbon number ranges of C9-C15, C9-C24, C10-C21, C10-C28, and C9-C17 for PP, PET, HDPE, LDPE, and PS, respectively. If implemented, the study will prove to be beneficial and contribute to mitigating the major energy and environmental issues of developing countries, as well as enhance entrepreneurship opportunities by replicating the process at small-scale and industrial levels.