Exploring the Spectrum of RHOBTB2 Variants Associated with Developmental Encephalopathy 64: A Case Series and Literature Review.

Background: Rho-related BTB domain-containing protein 2 (RHOBTB2) is a protein that interacts with cullin-3, a crucial E3 ubiquitin ligase for mitotic cell division. RHOBTB2 has been linked to early infantile epileptic encephalopathy, autosomal dominant type 64 (OMIM618004), in 34 reported patients. Methods: We present a case series of seven patients with RHOBTB2-related disorders (RHOBTB2-RD), including a description of a novel heterozygous variant. We also reviewed previously published cases of RHOBTB2-RD. Results: The seven patients had ages ranging from 2 years and 8 months to 26 years, and all had experienced seizures before the age of one (onset, 4-12 months, median, 4 months), including various types of seizures. All patients in this cohort also had a movement disorder (onset, 0.3-14 years, median, 1.5 years). Six of seven had a baseline movement disorder, and one of seven only had paroxysmal dystonia. Stereotypies were noted in four of six, choreodystonia in three of six, and ataxia in one case with multiple movement phenotypes at baseline. Paroxysmal movement disorders were observed in six of seven patients for whom carbamazepine or oxcarbazepine treatment was effective in controlling acute or paroxysmal movement disorders. Four patients had acute encephalopathic episodes at ages 4 (one patient) and 6 (three patients), which improved following treatment with methylprednisolone. Magnetic resonance imaging scans revealed transient fluid-attenuated inversion recovery abnormalities during these episodes, as well as myelination delay, thin corpus callosum, and brain atrophy. One patient had a novel RHOBTB2 variant (c.359G>A/p.Gly120Glu). Conclusion: RHOBTB2-RD is characterized by developmental delay or intellectual disability, early-onset seizures, baseline movement disorders, acute or paroxysmal motor phenomena, acquired microcephaly, and episodes of acute encephalopathy. Early onsets of focal dystonia, acute encephalopathic episodes, episodes of tongue protrusion, or peripheral vasomotor disturbances are important diagnostic clues. Treatment with carbamazepine or oxcarbazepine was found to be effective in controlling acute or paroxysmal movement disorders. Our study highlights the clinical features and treatment response of RHOBTB2-RD.

Expanding the phenotypic spectrum of TRAPPC11-related muscular dystrophy: 25 Roma individuals carrying a founder variant.

BACKGROUND: Limb-girdle muscular dystrophies (LGMD) are a heterogeneous group of genetically determined muscle disorders. TRAPPC11-related LGMD is an autosomal-recessive condition characterised by muscle weakness and intellectual disability. METHODS: A clinical and histopathological characterisation of 25 Roma individuals with LGMD R18 caused by the homozygous TRAPPC11 c.1287+5G>A variant is reported. Functional effects of the variant on mitochondrial function were investigated. RESULTS: The c.1287+5G>A variant leads to a phenotype characterised by early onset muscle weakness, movement disorder, intellectual disability and elevated serum creatine kinase, which is similar to other series. As novel clinical findings, we found that microcephaly is almost universal and that infections in the first years of life seem to act as triggers for a psychomotor regression and onset of seizures in several individuals with TRAPPC11 variants, who showed pseudometabolic crises triggered by infections. Our functional studies expanded the role of TRAPPC11 deficiency in mitochondrial function, as a decreased mitochondrial ATP production capacity and alterations in the mitochondrial network architecture were detected. CONCLUSION: We provide a comprehensive phenotypic characterisation of the pathogenic variant TRAPPC11 c.1287+5G>A, which is founder in the Roma population. Our observations indicate that some typical features of golgipathies, such as microcephaly and clinical decompensation associated with infections, are prevalent in individuals with LGMD R18.

Outbreak of Enterovirus Infection with Neurological Presentations in a Pediatric Population in Northern Spain: A Clinical Observational Study.

OBJECTIVE: The study aimed to describe the cases of neurological disease related to the outbreak of enterovirus (EV) in three regions in Northern Spain during 2016. MATERIALS AND METHODS: Multicenter retrospective observational study. Clinical, radiological, and microbiological data were analyzed from patients younger than 15 years with confirmed EV-associated neurological disease admitted to 10 hospitals of Asturias, Cantabria, and Castile and Leon between January 1 and December 31, 2016. RESULTS: Fifty-five patients were included. Median age was 24 months (interquartile range = 18.5 months). Fifteen patients were classified as aseptic meningitis (27.3%). In total, 37 cases presented brainstem encephalitis (67.3%), 25 of them due to EV-A71 with excellent prognosis (84.6% asymptomatic 2 months following the onset). Three cases of acute flaccid myelitis (5.5%) by EV-D68 were reported and presented persistent paresis 2 months following the onset. Microbiological diagnosis by reverse transcriptase polymerase chain reaction was performed in all cases, finding EV in cerebrospinal fluid in meningitis, but not in brainstem encephalitis and acute flaccid myelitis, where EV was found in respiratory or rectal samples. Step therapy was administrated with intravenous immunoglobulin (IVIG; 32.7%), methylprednisolone (10%), and plasmapheresis (3.6%). Four patients received fluoxetine (7.3%). Twenty patients needed to be admitted to pediatric intensive care unit (36.4%). CONCLUSION: Clinical, microbiological, and radiological diagnosis is essential in outbreaks of EV neurological disease, taking into account that it can be difficult to identify EV-A71 and EV-D68 in CSF, requiring throat or rectal samples. There is not specific treatment to these conditions and the efficacy and understanding of the mechanism of action of immune-modulatory treatment (IVIG, corticosteroids, and plasmapheresis) is limited.

Efficacy of the Ketogenic Diet for the Treatment of Refractory Childhood Epilepsy: Cerebrospinal Fluid Neurotransmitters and Amino Acid Levels.

OBJECTIVE: The mechanisms of the ketogenic diet remain unclear, but several predictors of response have been proposed. We aimed is to study the relationship between the etiology of epilepsy, cerebrospinal fluid neurotransmitters, pterins, and amino acids, and response to a ketogenic diet. METHODS: We studied 60 patients who began classic ketogenic diet treatment for refractory epilepsy. In 24 of 60 individuals, we analyzed cerebrospinal fluid neurotransmitters, pterins, and amino acids in baseline conditions. Mean age at epilepsy onset was 24 months, 83.3% were focal epilepsies, and in 51.7% the etiology of the epilepsy was unknown. RESULTS: Six months after initiating the ketogenic diet, it was effective (greater than a 50% reduction in seizure frequency) in 31.6% of patients. We did not find a link between rate of efficacy for the ketogenic diet and etiologies of epilepsy, nor did we find a link between the rate of efficacy for the ketogenic diet and cerebrospinal fluid pterins and biogenic amines concentrations. However, we found statistically significant differences for lysine and arginine values in the cerebrospinal fluid between ketogenic diet responders and nonresponders, but not for the other amino acids analyzed. SIGNIFICANCE: The values of some amino acids were significantly different in relationship with the ketogenic diet efficacy; however, the epilepsy etiology and the cerebrospinal fluid biogenic amine and pterin values were not.