GABRA1-Related Disorders: From Genetic to Functional Pathways.

OBJECTIVE: Variants in GABRA1 have been associated with a broad epilepsy spectrum, ranging from genetic generalized epilepsies to developmental and epileptic encephalopathies. However, our understanding of what determines the phenotype severity and best treatment options remains inadequate. We therefore aimed to analyze the electroclinical features and the functional effects of GABRA1 variants to establish genotype-phenotype correlations. METHODS: Genetic and electroclinical data of 27 individuals (22 unrelated and 2 families) harboring 20 different GABRA1 variants were collected and accompanied by functional analysis of 19 variants. RESULTS: Individuals in this cohort could be assigned into different clinical subgroups based on the functional effect of their variant and its structural position within the GABRA1 subunit. A homogenous phenotype with mild cognitive impairment and infantile onset epilepsy (focal seizures, fever sensitivity, and electroencephalographic posterior epileptiform discharges) was described for variants in the extracellular domain and the small transmembrane loops. These variants displayed loss-of-function (LoF) effects, and the patients generally had a favorable outcome. A more severe phenotype was associated with variants in the pore-forming transmembrane helices. These variants displayed either gain-of-function (GoF) or LoF effects. GoF variants were associated with severe early onset neurodevelopmental disorders, including early infantile developmental and epileptic encephalopathy. INTERPRETATION: Our data expand the genetic and phenotypic spectrum of GABRA1 epilepsies and permit delineation of specific subphenotypes for LoF and GoF variants, through the heterogeneity of phenotypes and variants. Generally, variants in the transmembrane helices cause more severe phenotypes, in particular GoF variants. These findings establish the basis for a better understanding of the pathomechanism and a precision medicine approach in GABRA1-related disorders. Further studies in larger populations are needed to provide a conclusive genotype-phenotype correlation. ANN NEUROL 2023.

Defining the electroclinical phenotype and outcome of PCDH19-related epilepsy: A multicenter study.

OBJECTIVE: PCDH19-related epilepsy is an epileptic syndrome with infantile onset, characterized by clustered and fever-induced seizures, often associated with intellectual disability (ID) and autistic features. The aim of this study was to analyze a large cohort of patients with PCDH19-related epilepsy and better define the epileptic phenotype, genotype-phenotype correlations, and related outcome-predicting factors. METHODS: We retrospectively collected genetic, clinical, and electroencephalogram (EEG) data of 61 patients with PCDH19-related epilepsy followed at 15 epilepsy centers. All consecutively performed EEGs were analyzed, totaling 551. We considered as outcome measures the development of ID, autistic spectrum disorder (ASD), and seizure persistence. The analyzed variables were the following: gender, age at onset, age at study, genetic variant, fever sensitivity, seizure type, cluster occurrence, status epilepticus, EEG abnormalities, and cognitive and behavioral disorders. Receiver operating characteristic curve analysis was performed to evaluate the age at which seizures might decrease in frequency. RESULTS: At last follow-up (median = 12 years, range = 1.9-42.1 years), 48 patients (78.7%) had annual seizures/clusters, 13 patients (21.3%) had monthly to weekly seizures, and 12 patients (19.7%) were seizure-free for ≥2 years. Receiver operating characteristic analysis showed a significant decrease of seizure frequency after the age of 10.5 years (sensitivity = 81.0%, specificity = 70.0%). Thirty-six patients (59.0%) had ID and behavioral disturbances. ASD was present in 31 patients. An earlier age at epilepsy onset emerged as the only predictive factor for ID (P = 0.047) and ASD (P = 0.014). Conversely, age at onset was not a predictive factor for seizure outcome (P = 0.124). SIGNIFICANCE: We found that earlier age at epilepsy onset is related to a significant risk for ID and ASD. Furthermore, long-term follow-up showed that after the age of 10 years, seizures decrease in frequency and cognitive and behavioral disturbances remain the primary clinical problems.

Snyder-Robinson syndrome: a novel nonsense mutation in spermine synthase and expansion of the phenotype.

Snyder-Robinson syndrome is a rare form of X-linked intellectual disability caused by mutations in the spermine synthase (SMS) gene, and characterized by intellectual disability, thin habitus with diminished muscle mass, osteoporosis, kyphoscoliosis, facial dysmorphism (asymmetry, full lower lip), long great toes, and nasal or dysarthric speech. Physical signs seem to evolve from childhood to adulthood. We describe the first Italian patient with Snyder-Robinson syndrome and a novel nonsense mutation in SMS (c.200G>A; p.G67X). Apart from the typical features of the syndrome, the index patient presented with an ectopic right kidney and epilepsy from the first year of age that was characterized by focal motor seizures and negative myoclonus. The clinical and molecular evaluation of this family and the review of the literature expand the phenotype of Snyder-Robinson syndrome to include myoclonic or myoclonic-like seizures (starting even in the first years of life) and renal abnormalities in affected males.

Emotion recognition and theory of mind weakness at school age in children born preterm.

BACKGROUND: Social immaturity and impaired social functioning are topical issues in recent research in the field of prematurity. Social-cognitive skills and emotional processing, the neuropsychological correlates underlying social behavior, are key aspects of these issues. METHODS: We examined 48 Italian primary school children who had been born preterm with a very low birthweight (26 males; mean age 9 years; SD 1.2). All had shown a normal neonatal cerebral ultrasound at term age, and showed a normal neurological examination and average IQ at the time of the study. Social skills and executive functions (EFs) and their correlations with a set of neonatal, sociodemographic, cognitive and adaptive parameters were investigated using standardized scales and questionnaires. RESULTS: Emotion recognition (ER) was impaired in 48% and Theory of Mind (ToM) in 8% of the children. These deficits showed no relationship with EFs or IQ, or with gestational age, birthweight, age or gender. Correlations between ER and socioeconomic status and between ToM and adaptive functioning were documented. CONCLUSIONS: We suggest that adaptive and behavioral problems in preterm children may be linked to neurocognitive dysfunction characterized by deficits in social skills, which may be driven by socioeconomic, family and environmental factors, socioeconomic status in particular. Possible neural circuitry impairments underlying these deficits are discussed.

Connections Between Febrile Infection-Related Epilepsy Syndrome and Autoimmune Encephalitis. A Case Report of a Child With New Anti-neuronal Antibodies.

Acute encephalitis and febrile infection-related epilepsy syndrome (FIRES) are debilitating neurological disorders. It is increasingly accepted that FIRES should be considered an autoinflammation-mediated epileptic encephalopathy, but the debate about its etiopathogenesis is still very much open. Despite showing a considerable overlap with encephalitis, it continues to be regarded as a distinct entity. We describe the case of a previously healthy 5-year-old child who, following a fever, developed acute encephalopathy, status epilepticus, neurological, neuropsychological, and psychiatric manifestations, and claustrum involvement on MRI. At symptom onset, his clinical and instrumental data met the diagnostic criteria for both FIRES and acute encephalitis. He received benzodiazepines, levetiracetam, phenytoin, phenobarbital, thiopental, and first-line immunotherapy for acute inflammatory encephalopathy (intravenous methylprednisolone and immunoglobulins), without substantial improvement. Following the detection of anti-neuronal antibodies through immunohistochemistry performed on rat brain slices, he received therapeutic plasma exchange (TPE). His neurological and behavioral conditions improved drastically and his antibody titer fell sharply from the first to the last course of PE. Claustrum abnormalities on MRI disappeared. The patient's long-term outcome is favorable. At 13 months after discharge, he experienced a focal seizure and carbamazepine was started, achieving seizure control. At 10 years of age, he is still on carbamazepine, with well-controlled seizures, focal EEG abnormalities, and an otherwise normal neurological and cognitive profile and normal MRI. This case strengthens the view that FIRES might constitute the initial clinical presentation of a CNS inflammatory disease that could have, among multiple distinct etiologies, an autoimmune cause. Immunological and specific second- or third-level investigations including immunohistochemistry should be included in the diagnostic work up of patients with FIRES-like phenotypes. PE could be effective in this subset of patients, protecting them from long-term neurological sequelae.

Multidisciplinary Management of Children with Occult Spinal Dysraphism: A Comprehensive Journey from Birth to Adulthood.

Occult spinal dysraphism (OSD) comprises different forms of failure in embryogenic development that can lead to genitourinary, spinal, or lower limb alterations, thus determining progressive neurological deterioration. The correct management of children harboring OSD represents a significant issue during their life up to adulthood. However, patients often have to entertain individual consultations with each specialist. We settled on a multidisciplinary team comprising pediatric neurosurgeons, urologists, neurologists, orthopedists, and other supporting physicians. We present the results of such actions by analyzing a series of 141 children with OSD subjected to neurosurgical procedures, evaluating the impact of multidisciplinary management on outcomes. We also evaluated the specific actions according to the different ages of OSD patients from birth to adulthood to provide a schematic plan that could represent a basis for establishing and disseminating the need for a multidisciplinary approach in OSD management. The multidisciplinary team allows all consultants to see the patient together, covering specific aspects of history and examination pertinent to their management. Offering a one-stop service prevents coordination issues between the different medical teams, avoids delays or cancellations of the various appointments, optimizes cost-effectiveness, and improves efficiency and parents' satisfaction.

The development of visual object recognition in school-age children.

This study documents the age-dependent development of visual object recognition abilities in 115 children aged 6 to 11 years, using a battery of neuropsychological tests based on Marrs model (Efron test, Warringtons Figure-Ground Test, Street Completion Test, Poppelreuter-Ghent Test, a selection of stimuli from the Birmingham Object Recognition Battery, a series of color photographs of objects presented from unusual perspectives or illuminated in unusual ways). The results suggest a maturation of complex visual perceptual abilities, possibly related to the development of the cerebral processes involved in object recognition, and could be the starting point for future investigations of these skills in impaired populations.