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1.
J Neurosci Rural Pract ; 10(4): 613-616, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31831980

RESUMO

Objective Pyridoxine responsive seizures (PDRs) are characterized by early-onset seizures and epileptic encephalopathy (neonates and infants) which respond to pyridoxine. Any type of seizures can be the first presentation of PDRs in these children. The aim of this 20-year retrospective study was to report the profile of 35 children with PDRs. Materials and Methods Neonatal and infantile seizures responding to pyridoxine were analyzed retrospectively from 1998 to 2018. Depending on the clinical features, laboratory results, and genetic study, they were divided into following four groups: (A) responders with α-aminoadipic semialdehyde dehydrogenase 7A1 ( ALDH7A1 ) mutation, (B) responders with pyridoxal phosphate homeostasis protein (PLPHP) mutation, (C) responders with none of these two known mutations, (D) and responders in combination with antiepileptic medications. Results Sixteen of 35 children had genetic mutation, 4 with ALDH7A1 mutation, and 12 with PLPHP mutation recently described. Nineteen of 35 children had no genetic positivity. Conclusion A large number of children with pyridoxine response do not have known genetic confirmation. Over time, new genes, responsible for pyridoxine dependency, may be identified or an unknown metabolic disorder may be seen in these children.

2.
Brain ; 142(3): 542-559, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30668673

RESUMO

Biallelic pathogenic variants in PLPBP (formerly called PROSC) have recently been shown to cause a novel form of vitamin B6-dependent epilepsy, the pathophysiological basis of which is poorly understood. When left untreated, the disease can progress to status epilepticus and death in infancy. Here we present 12 previously undescribed patients and six novel pathogenic variants in PLPBP. Suspected clinical diagnoses prior to identification of PLPBP variants included mitochondrial encephalopathy (two patients), folinic acid-responsive epilepsy (one patient) and a movement disorder compatible with AADC deficiency (one patient). The encoded protein, PLPHP is believed to be crucial for B6 homeostasis. We modelled the pathogenicity of the variants and developed a clinical severity scoring system. The most severe phenotypes were associated with variants leading to loss of function of PLPBP or significantly affecting protein stability/PLP-binding. To explore the pathophysiology of this disease further, we developed the first zebrafish model of PLPHP deficiency using CRISPR/Cas9. Our model recapitulates the disease, with plpbp-/- larvae showing behavioural, biochemical, and electrophysiological signs of seizure activity by 10 days post-fertilization and early death by 16 days post-fertilization. Treatment with pyridoxine significantly improved the epileptic phenotype and extended lifespan in plpbp-/- animals. Larvae had disruptions in amino acid metabolism as well as GABA and catecholamine biosynthesis, indicating impairment of PLP-dependent enzymatic activities. Using mass spectrometry, we observed significant B6 vitamer level changes in plpbp-/- zebrafish, patient fibroblasts and PLPHP-deficient HEK293 cells. Additional studies in human cells and yeast provide the first empirical evidence that PLPHP is localized in mitochondria and may play a role in mitochondrial metabolism. These models provide new insights into disease mechanisms and can serve as a platform for drug discovery.


Assuntos
Epilepsia/etiologia , Proteínas/genética , Proteínas/metabolismo , Animais , Modelos Animais de Doenças , Epilepsia/fisiopatologia , Feminino , Células HEK293 , Humanos , Masculino , Fenótipo , Fosfato de Piridoxal/uso terapêutico , Piridoxina/deficiência , Vitamina B 6/metabolismo , Deficiência de Vitamina B 6/genética , Deficiência de Vitamina B 6/metabolismo , Peixe-Zebra
3.
Sultan Qaboos Univ Med J ; 18(2): e223-e227, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-30210856

RESUMO

Myasthaenia gravis (MG) is an auto-immune disease involving the postsynaptic receptors in the neuromuscular junction. The condition is characterised by fatigable weakness of the skeletal muscles and is uncommon in children. Acetylcholinesterase inhibitors and immune-modifying medications are usually considered the mainstay of treatment. However, these medications have to be given on a lifelong basis so that patients remain in remission; furthermore, drug-related side-effects can have a major impact on quality of life. We report two paediatric cases who were treated for MG at the Sultan Qaboos University Hospital, Muscat, Oman, in 2007 and 2008, respectively. Rituximab was eventually administered to each patient after their condition failed to improve despite several years of standard treatment with acetylcholinesterase inhibitors and immune-modifying medications. Overall, rituximab resulted in complete remission in one case and significant clinical improvement in the other case.


Assuntos
Fatores Imunológicos/uso terapêutico , Miastenia Gravis/tratamento farmacológico , Rituximab/uso terapêutico , Criança , Pré-Escolar , Feminino , Humanos , Omã , Qualidade de Vida
4.
Sultan Qaboos Univ Med J ; 17(2): e202-e208, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28690893

RESUMO

OBJECTIVES: Most children presenting with febrile illness require a blood culture to determine the causative organism as well as its sensitivity to antibiotics. However, false-positive results lead to unnecessary hospitalisations, prescriptions and tests. This study aimed to evaluate the impact of false-positive blood cultures among a paediatric population at a tertiary hospital in Oman. METHODS: This retrospective study included all 225 children <13 years old with positive blood cultures who presented to the Sultan Qaboos University Hospital, Muscat, Oman, between July 2011 and December 2013. Blood cultures were reviewed to determine whether they were true-positive or contaminated. RESULTS: A total of 344 positive blood cultures were recorded during the study period, of which 185 (53.8%) were true-positive and 159 (46.2%) were contaminated. Most true-positive isolates (26.5%) were coagulase-negative Staphylococcus spp. (CONS) followed by Escherichia coli (9.7%), while the majority of contaminated isolates were CONS (67.9%) followed by Streptococcus spp. (6.9%). Children with contaminated cultures were significantly younger (P <0.001) while those with true-positive cultures required significantly more frequent hospital admissions, longer hospital stays and more frequent antibiotic prescriptions (P <0.001 each). Chronic illness and mortality was significantly more frequent among those with true-positive cultures (P <0.001 and 0.04, respectively). While white blood cell and absolute neutrophil counts were significantly higher in true-positive cultures (P <0.001 each), there was no significant difference in C-reactive protein (CRP) level (P = 0.791). CONCLUSION: In this population, CRP level was not an adequate marker to differentiate between true- and false-positive cultures. A dedicated well-trained phlebotomy team for paediatric patients is essential.


Assuntos
Bactérias/isolamento & purificação , Hemocultura , Febre/microbiologia , Fatores Etários , Bactérias/classificação , Criança , Pré-Escolar , Escherichia coli/isolamento & purificação , Reações Falso-Positivas , Feminino , Humanos , Lactente , Masculino , Omã , Estudos Retrospectivos , Staphylococcus/isolamento & purificação , Streptococcus/isolamento & purificação , Centros de Atenção Terciária
6.
Sultan Qaboos Univ Med J ; 13(3): 371-9, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23984021

RESUMO

OBJECTIVES: The aim of the study was to explore the spectrum of hereditary spastic paraplegia (HSP) in children in Oman. METHODS: This retrospective study was carried out between January 1994 and August 2011 on children with delayed development, gait disorders and motor handicaps, with signs of symmetrical pyramidal tract involvement. A detailed perinatal and family history, including the age of onset of symptoms, was recorded. The children were labelled as having either the pure or complicated form of HSP based on the established diagnostic criteria. In families with more than one affected child, parents and all other siblings were also examined. RESULTS: Within the study, 74 children from 31 families were diagnosed with HSP. Parental consanguinity was seen in 91% of cases, with 44 children (59.4%) experiencing onset of the disease under one year of age. Complicated HSP was the most common type, seen in 81.1%. Speech involvement, mental retardation, and epilepsy were the most common associated abnormalities. Nonspecific white matter changes and corpus callosum abnormalities were noted in 24.3% of cases on magnetic resonance imaging. CONCLUSION: The study described clinical features of 74 children with HSP. Autosomal recessive complicated HSP was seen in 81.1% of cases.

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