Publications by authors named "Roser Pons"

Background: Patients with mutations in the monocarboxylate transporter 8 (MCT8, SLC16A2) suffer from X-linked recessive Allan-Herndon-Dudley syndrome (AHDS), which is characterized by developmental delay and a severe movement disorder. Current trials using thyroid hormone derivatives to overcome the transporter defect have failed to achieve patient-oriented therapeutic goals.

Objectives: Our aim was to define the type of movement disorder in AHDS in an observational cohort study and to investigate the causative role of the dopaminergic system.

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Background: Developmental and epileptic encephalopathy (DEE) includes diseases where there is developmental impairment related to both the underlying etiology independent of epileptiform activity and the epileptic encephalopathy. Patients often present with movement disorders (MD). This study aims to delineate the motor phenotype in a cohort of patients with DEE.

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, the gene encoding for the Nav1.1 channel, exhibits dominant interneuron-specific expression, whereby variants disrupting the channel's function affect the initiation and propagation of action potentials and neuronal excitability causing various types of epilepsy. Dravet syndrome (DS), the first described clinical presentation of SCN1A channelopathy, is characterized by severe myoclonic epilepsy in infancy (SMEI).

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Introduction/aims: Myotonia congenita (MC) is the most common hereditary channelopathy in humans. Characterized by muscle stiffness, MC may be transmitted as either an autosomal dominant (Thomsen) or a recessive (Becker) disorder. MC is caused by variants in the voltage-gated chloride channel 1 (CLCN1) gene, important for the normal repolarization of the muscle action potential.

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The objective of the study is to evaluate the evolving phenotype and genetic spectrum of patients with succinic semialdehyde dehydrogenase deficiency (SSADHD) in long-term follow-up. Longitudinal clinical and biochemical data of 22 pediatric and 9 adult individuals with SSADHD from the patient registry of the International Working Group on Neurotransmitter related Disorders (iNTD) were studied with in silico analyses, pathogenicity scores and molecular modeling of ALDH5A1 variants. Leading initial symptoms, with onset in infancy, were developmental delay and hypotonia.

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Background: Participation in family, recreational activities and self-care is an integral part of health. It is also a main outcome of rehabilitation services for children and adolescents with disabilities. However, there are currently no available tools in Greek to assess participation in young children.

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17p13 is a chromosomal region characterized by genomic instability due to high gene density leading to multiple deletion and duplication events. 17p13.3 microduplication syndrome is a rare condition, reported only in 40 cases worldwide, which is found in the Miller-Dieker chromosomal region, presenting a wide range of phenotypic manifestations.

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Elevated serum prolactin concentrations occur in inherited disorders of biogenic amine metabolism because dopamine deficiency leads to insufficient inhibition of prolactin secretion. This work from the International Working Group on Neurotransmitter Related Disorders (iNTD) presents the results of the first standardized study on levodopa-refractory hyperprolactinemia (LRHP; >1000 mU/L) and pituitary magnetic resonance imaging (MRI) abnormalities in patients with inherited disorders of biogenic amine metabolism. Twenty-six individuals had LRHP or abnormal pituitary findings on MRI.

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The autosomal recessive defect of aromatic L-amino acid decarboxylase (AADC) leads to a severe neurological disorder with manifestation in infancy due to a pronounced, combined deficiency of dopamine, serotonin and catecholamines. The success of conventional drug treatment is very limited, especially in patients with a severe phenotype. The development of an intracerebral AAV2-based gene delivery targeting the putamen or substantia nigra started more than 10 years ago.

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Article Synopsis
  • AADC deficiency is a rare genetic disorder that impacts the production of neurotransmitters like dopamine, norepinephrine, epinephrine, and serotonin, diagnosed via CSF/plasma analysis, AADC activity measurement, and genetic testing for the DDC gene.
  • In a study involving 348 patients, researchers identified 26 new DDC variants and analyzed their prevalence, finding that a specific splice variant, c.714+4A>T, was the most common, particularly prevalent in Taiwan and China.
  • The majority of identified genotypes were classified as pathogenic or likely pathogenic, with only one benign variant reported, and most AADC protein variants impacted protein function significantly based on their structural characteristics.*
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Cafe-au-lait macules are the most distinctive clinical finding in neurofibromatosis type I. The aim of this prospective study of Greek children diagnosed with neurofibromatosis type I was to describe the dermatological phenotype and to analyse the characteristics of cafe-au-lait macules and their association with genotype. Pigment intensity and melatonin content of cafe-au-lait macules were measured with a narrowband spectrophotometer.

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Background And Objective: GLUT1 deficiency syndrome (Glut1DS) is a treatable neurometabolic disease that causes a wide range of neurologic symptoms in children and adults. However, its diagnosis relies on an invasive test, that is, a lumbar puncture (LP) to measure glycorrhachia, and sometimes complex molecular analyses of the gene. This procedure limits the number of patients able to receive the standard of care.

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Objectives: Genetics of epilepsy are highly heterogeneous and complex. Lesions detected involve genes encoding various types of channels, transcription factors, and other proteins implicated in numerous cellular processes, such as synaptogenesis. Consequently, a wide spectrum of clinical presentations and overlapping phenotypes hinders differential diagnosis and highlights the need for molecular investigations toward delineation of underlying mechanisms and final diagnosis.

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Objective: To analyse the motor phenotype with a focus on bradykinesia in children with Cerebral Palsy (CP) in the setting of periventricular leukomalacia (PVL).

Methodology: Analysis of a cohort of 25 children with CP and PVL. The Gross Motor Function Classification System (GMFCS) and the Manual Ability Classification System (MACS) were used to classify the severity of motor function.

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Background: Biogenic amines and pterins analysis in cerebrospinal fluid (CSF) are reliable biomarkers for the diagnosis of inherited disorders of monoamine neurotransmitters.

Objective: The objectives of this study were the establishment of reference values of CSF biogenic amine metabolites in a cohort of Greek children, the detection of primary defects of biogenic amine metabolism, and the assessment of biogenic amine metabolites in children with different neurological disorders.

Methods: CSF biogenic amine metabolites and pterins (biopterin and neopterin) were analyzed using high-performance liquid chromatography with electrochemical and fluorescence detection.

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Our clinical series comprises 124 patients with movement disorders (MDs) and/or ataxia with cerebellar atrophy (CA), many of them showing signs of neurodegeneration with brain iron accumulation (NBIA). Ten NBIA genes are accepted, although isolated cases compatible with abnormal brain iron deposits are known. The patients were evaluated using standardised clinical assessments of ataxia and MDs.

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Article Synopsis
  • The study investigates the genetic landscape and key clinical characteristics of complex, early-onset, monogenic hyperkinetic movement disorders in patients recruited from 14 international centers.
  • Researchers found pathogenic variants in 17 different genes across 140 patients, with the majority exhibiting generalized hyperkinetic movements and various associated motor symptoms.
  • The findings suggest that those with generalized hyperkinetic movements tend to have an earlier disease onset, and highlight the need for disease-specific treatments tailored to individual genetic conditions.
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Heart failure (HF) patients frequently develop brain deficits that lead to cognitive dysfunction (CD), which may ultimately also affect survival. There is an important interaction between brain and heart that becomes crucial for survival in patients with HF. Our aim was to review the brain/heart interactions in HF and discuss the emerging role of combined brain/heart magnetic resonance imaging (MRI) evaluation.

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Transcriptional coregulators modulate the efficiency of transcription factors. Bi-allelic variants in TRIP4 and ASCC1, two genes that encode members of the tetrameric coregulator ASC-1, have recently been associated with congenital bone fractures, hypotonia, and muscular dystrophy in a total of 22 unrelated families. Upon exome sequencing and data repository mining, we identified six new patients with pathogenic homozygous variants in either TRIP4 (n = 4, two novel variants) or ASCC1 (n = 2, one novel variant).

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Pediatric-onset multiple sclerosis (MS, POMS) accounts for 3-5% of all MS cases and is characterized by a highly inflammatory profile, often warranting treatment with high-efficacy agents. Our aim is to present real-world data of a series of 18 Hellenic POMS patients treated with natalizumab (NTZ) either as adolescents or as adults, after high disease activity has efficiently subsided. Clinical and imaging/laboratory data from 18 POMS patients who have received at least one NTZ infusion were selected in this single-center retrospective observational study.

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Purpose: Pathogenic variants in GABRB3 have been associated with a spectrum of phenotypes from severe developmental disorders and epileptic encephalopathies to milder epilepsy syndromes and mild intellectual disability (ID). In this study, we analyzed a large cohort of individuals with GABRB3 variants to deepen the phenotypic understanding and investigate genotype-phenotype correlations.

Methods: Through an international collaboration, we analyzed electro-clinical data of unpublished individuals with variants in GABRB3, and we reviewed previously published cases.

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