Publications by authors named "Charlotte A Haaxma"

Thrombotic microangiopathy (TMA) in association with RNA exosome encoding mutations has only recently been recognized. Here, we present an infant (female) with an mutation (c.230_232del p.

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NANS-CDG is a congenital disorder of glycosylation (CDG) caused by biallelic variants in NANS, encoding an essential enzyme in de novo sialic acid synthesis. It presents with intellectual developmental disorder (IDD), skeletal dysplasia, neurologic impairment, and gastrointestinal dysfunction. Some patients suffer progressive intellectual neurologic deterioration (PIND), emphasizing the need for a therapy.

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Purpose: For patients with inherited metabolic disorders (IMDs), any diagnostic delay should be avoided because early initiation of personalized treatment could prevent irreversible health damage. To improve diagnostic interpretation of genetic data, gene function tests can be valuable assets. For IMDs, variant-transcending functional tests are readily available through (un)targeted metabolomics assays.

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Transportin-2 (TNPO2) mediates multiple pathways including non-classical nucleocytoplasmic shuttling of >60 cargoes, such as developmental and neuronal proteins. We identified 15 individuals carrying de novo coding variants in TNPO2 who presented with global developmental delay (GDD), dysmorphic features, ophthalmologic abnormalities, and neurological features. To assess the nature of these variants, functional studies were performed in Drosophila.

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Article Synopsis
  • NANS-CDG is a newly identified genetic disorder caused by mutations in a gene critical for sialic acid synthesis, leading to various developmental issues.
  • An observational study on nine patients revealed consistent symptoms such as intellectual disabilities, facial dysmorphisms, and skeletal abnormalities, along with newly observed issues like ophthalmological problems and gastrointestinal dysfunction.
  • Biochemical analysis showed elevated levels of -acetylmannosamine (ManNAc) correlate with clinical severity, and genetic screening identified novel mutations, with potential treatment showing improved development in one patient.
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  • The study investigated the clinical characteristics and genetic variations associated with the DHX30-related neurodevelopmental disorder, especially focusing on new missense variants in the gene.
  • Researchers collected clinical and genetic data from affected individuals via social media, collaboration networks, and analyzed the effects of these variants on cellular functions and development using various experimental models, including zebrafish.
  • Findings revealed that individuals with missense variants presented with severe developmental issues, while those with variants leading to milder haploinsufficiency showed less severe symptoms, suggesting the presence of two distinct clinical subtypes based on the type and location of the genetic variants.
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Guanidinoacetate methyltransferase (GAMT) deficiency is a creatine deficiency disorder and an inborn error of metabolism presenting with progressive intellectual and neurological deterioration. As most cases are identified and treated in early childhood, adult phenotypes that can help in understanding the natural history of the disorder are rare. We describe two adult cases of GAMT deficiency from a consanguineous family in Pakistan that presented with a history of global developmental delay, cognitive impairments, excessive drooling, behavioral abnormalities, contractures and apparent bone deformities initially presumed to be the reason for abnormal gait.

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The RNA exosome is an essential ribonuclease complex required for processing and/or degradation of both coding and non-coding RNAs. We identified five patients with biallelic variants in EXOSC5, which encodes a structural subunit of the RNA exosome. The clinical features of these patients include failure to thrive, short stature, feeding difficulties, developmental delays that affect motor skills, hypotonia and esotropia.

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NGLY1 encodes the enzyme N-glycanase that is involved in the degradation of glycoproteins as part of the endoplasmatic reticulum-associated degradation pathway. Variants in this gene have been described to cause a multisystem disease characterized by neuromotor impairment, neuropathy, intellectual disability, and dysmorphic features. Here, we describe four patients with pathogenic variants in NGLY1.

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  • Biallelic pathogenic variants in the PLPBP gene cause a unique form of vitamin B6-dependent epilepsy, which can lead to severe consequences such as status epilepticus and death during infancy if untreated.
  • Researchers identified 12 new patients and six novel variants linked to this condition, with the most severe cases associated with variants that cause loss of function or destabilize the PLPBP protein.
  • A zebrafish model created using CRISPR/Cas9 mimics the disease's symptoms and shows that treatment with pyridoxine can alleviate seizures and prolong life, while also revealing important metabolic disruptions linked to the disease.
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Background: ATP8A2 mutations have recently been described in several patients with severe, early-onset hypotonia and cognitive impairment. The aim of our study was to characterize the clinical phenotype of patients with ATP8A2 mutations.

Methods: An observational study was conducted at multiple diagnostic centres.

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encodes Nav1.6, one of the main voltage-gated sodium channel subunits in the brain, and mutations lead to epileptic encephalopathy. Particular mutations render the mutant channel more susceptible to inhibition by phenytoin.

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Ataxia-telangiectasia is a rare, neurodegenerative, and multisystem disease, characterized by cerebellar ataxia, oculocutaneous telangiectasia, immunodeficiency, progressive respiratory failure, and an increased risk of malignancies. It demands specialized care tailored to the individual patient's needs. Besides the classic ataxia-telangiectasia phenotype, a variant phenotype exists with partly overlapping but some distinctive disease characteristics.

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Ataxia-telangiectasia (AT) is a neurodegenerative disorder characterized by ataxia, telangiectasia, and immunodeficiency. An increased risk of malignancies and respiratory diseases dramatically reduce life expectancy. To better counsel families, develop individual follow-up programs, and select patients for therapeutic trials, more knowledge is needed on factors influencing survival.

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Microtubules are dynamic cytoskeletal elements coordinating and supporting a variety of neuronal processes, including cell division, migration, polarity, intracellular trafficking, and signal transduction. Mutations in genes encoding tubulins and microtubule-associated proteins are known to cause neurodevelopmental and neurodegenerative disorders. Growing evidence suggests that altered microtubule dynamics may also underlie or contribute to neurodevelopmental disorders and neurodegeneration.

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Objective: The early infantile epileptic encephalopathy type 13 (EIEE13, OMIM #614558) results from de novo missense mutations of SCN8A encoding the voltage-gated sodium channel Nav1.6. More than 20% of patients have recurrent mutations in residues Arg1617 or Arg1872.

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Background: Response fluctuations and dyskinesias develop during the use of both levodopa (LD) and dopamine agonists (DA), but may not be equally disabling.

Objective: To compare the risk and time of onset of disabling response fluctuations and dyskinesias (DRFD) among patients with Parkinson's disease (PD) who were initially treated with either LD or DA.

Methods: Open cohort study of all consecutive de-novo PD patients in routine clinical practice, included over a period of 15 years (median follow-up: 8.

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Parkinson's disease (PD) is preceded by a premotor phase of unknown duration. Dopaminergic degeneration during this phase may lead to subtle cognitive and behavioural changes, such as decreased novelty seeking. Consequently, premotor subjects might be most comfortable in jobs that do not require optimal dopamine levels, leading to an overrepresentation in structured and predictable occupations, or an underrepresentation in artistic occupations.

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A neonate was born with a sacrococcygeal mass. Initially, spina bifida was suspected. However, neurological examination was unremarkable.

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Introduction: Freezing of gait (FOG) is both common and debilitating in patients with Parkinson's disease (PD). Future pathophysiology studies will depend critically upon adequate classification of patients as being either 'freezers' or 'non-freezers'. This classification should be based ideally upon objective confirmation by an experienced observer during clinical assessment.

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Aicardi-Goutières syndrome is a rare, genetically determined encephalopathy often resembling congenital infection. Mutations in the TREX1 gene are found in approximately 25% of patients. Aicardi-Goutières syndrome is usually inherited as an autosomal recessive trait, although a single case of a heterozygous TREX1 mutation associated with the syndrome has been reported.

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Early diagnosis of Parkinson's disease (PD) is important for putative neuroprotective therapies to be initiated in the earliest stage of the disease. We investigated whether a previously validated timed motor test (TMT) battery could detect subtle motor dysfunction in early PD patients and even in clinically unaffected limbs of strictly hemiparkinsonian patients. We assessed 107 PD patients (symptom duration View Article and Find Full Text PDF

The most widely used scale currently available for the clinical evaluation of motor dysfunction in Parkinson's disease (PD)-the Unified Parkinson's Disease Rating Scale-III (UPDRS-III) -is time-consuming, subjective, and has suboptimal sensitivity. A brief timed motor test (TMT) battery could possibly overcome these drawbacks. Two hundred eighty-eight PD patients (disease duration 3.

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Objective: To investigate gender differences in basic disease characteristics, motor deterioration and nigrostriatal degeneration in Parkinson's disease (PD).

Methods: We studied 253 consecutive PD patients who were not receiving levodopa or dopamine agonists (disease duration < or = 10 years). We investigated the influence of gender and oestrogen status on: (1) age at onset, (2) presenting symptom, (3) severity and progression of motor symptoms (Unified Parkinson's Disease Rating Scale III (UPDRS-III) scores) and (4) amount and progression of nigrostriatal degeneration ([123I]FP-CIT single photon emission computed tomography measurements).

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