De novo STXBP1 mutations are among the most frequent causes of epilepsy and encephalopathy. Most patients have severe to profound ID with little correlation among seizure onset, seizure severity, and the degree of ID. Accordingly, we hypothesize that seizure severity and ID present 2 independent dimensions of the STXBP1-E phenotype. STXBP1-E may be conceptualized as a complex neurodevelopmental disorder rather than a primary epileptic encephalopathy.
Unilateral motor seizures may be a specific clinical characteristic of SMEI caused by SCN1A mutations. Ten percent of SCN1A mutations are inherited from an asymptomatic or mildly affected parent, suggesting that SMEI is genetically heterogeneous. The increased frequency of familial epilepsy indicates that other genetic factors may contribute to this disorder.
SUMMARYFebrile seizures are the most common seizure disorder in childhood, affecting 2-5% of children. Simple febrile seizure is defined as a short (<15 min) generalized seizure, not recurring within 24 h, that occurs during a febrile illness not resulting from an acute disease of the nervous system in a child aged between 6 months and 5 years, with no neurologic deficits and no previous afebrile seizures. These recommendations address the instructions for management of the first febrile seizures, giving criteria for hospital admission, diagnosis, differential diagnosis, and treatment of a prolonged seizure. The authors stressed the benign prognosis of the majority of cases and the risk factors for recurrence of febrile seizures and appearance of epilepsy later on. Both continuous and intermittent anticonvulsant therapy are efficacious in preventing single febrile seizures, but side effects may be so important to overcome the benefits. These treatments are indicated in very selected patients.
Summary
Eyelid myoclonia with absences (EMA), or Jeavons syndrome, is a generalized epileptic condition clinically characterized by eyelid myoclonia (EM) with or without absences, eye closure‐induced electroencephalography (EEG) paroxysms, and photosensitivity; in addition, rare tonic–clonic seizures may also occur. Although first described in 1977 and widely reported by several authors within the last few years, EMA has not been yet recognized as a definite epileptic syndrome. However, when strict criteria are applied to the diagnosis, EMA appears to be a distinctive condition that could be considered a myoclonic epileptic syndrome, with myoclonia limited to the eyelids, rather than an epileptic syndrome with absences.
Summary
Heterozygous mutations of PRRT2, which encodes proline‐rich transmembrane protein 2, are associated with heterogeneous phenotypes including benign familial infantile seizures (BFIS), or familial paroxysmal kinesigenic dystonia (PKD). We report a consanguineous Italian family with BFIS/PKD phenotype that contained 14 living members with 6 affected individuals (four men, ranging in age from 6–44 years). We identified the reported c.649dupC (p.Arg217ProfsX8) mutation of PRRT2 gene that cosegregated with the disease and was not observed in 100 controls of matched ancestry. Four patients with BFIS phenotype were heterozygous for this mutation, including the consanguineous parents of the two affected brothers with more severe phenotypes of BFIS/PKD—mental retardation, episodic ataxia, and absences—who were the only individuals to carry a homozygous c.649dupC mutation. This family provides strong evidence that homozygous PRRT2 mutations give rise to more severe clinical disease of mental retardation, episodic ataxia, and absences, and, thus, enlarges the clinical spectrum related to PRRT2 mutations. Moreover, it suggests an additive effect of double dose of the genetic mutation and underscores the complexity of the phenotypic consequences of mutations in this gene.
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