Developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep in Saudi Arabia: Electroclinical, etiologic, genetic, and outcome multicenter study

OBJECTIVES

To investigate the clinical features of developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep (D/EE-SWAS), its electrographic characteristics, and etiology and to compare the effects of different treatment strategies on the outcomes using a Saudi Arabian database.

METHODS

This multicenter study included children with D/EE-SWAS who were evaluated between 2010 and 2020 at 11 tertiary centers. Data were collected on their baseline clinical features, etiologies, and treatment modalities. Seizure reduction, spike-wave index, and cognitive state were examined as potential therapeutic outcomes.

RESULTS

Ninety-one children were diagnosed with D/EE-SWAS, with a median age of 7 years (IQR: 3-5) and an almost equal sex distribution. The average age at which epilepsy was diagnosed was 3 years (IQR: 5-2). A genetic/metabolic etiology was found in 35.1% of the patients, and a structural etiology was found in 27.4%. Children with underlying genetic/metabolic diseases exhibited an earlier seizure onset (P = 0.001) than children with other etiologies. Benzodiazepines (76.6%) were the most common treatment, followed by steroids (51.9%). Sodium valproate (75%) was the most frequently used antiseizure medication, followed by levetiracetam (64.9%). Children with a later seizure onset were more likely to have better clinical responses (P = 0.046), EEG responses (P = 0.012), and cognitive outcomes (P = 0.006) than children with an earlier onset. Moreover, better seizure response and electrographic response were seen in patients with bilateral interictal discharges on the EEG than otherwise. Children had a higher likelihood of both clinical and electrographic improvement with combination therapy of benzodiazepines (P = 0.001) and steroids (P = 0.001) than with other therapies.

SIGNIFICANCE

This study shows a higher prevalence of genetic/metabolic causes and suggests the superior efficacy of combination therapy with steroids and benzodiazepines in D/EE-SWAS. Prospective studies that strictly assess the treatment protocols and outcomes are needed.

Phenotypical spectrum of cerebellar ataxia associated with a novel mutation in the CA8 gene, encoding carbonic anhydrase (CA) VIII

We define the neurological characteristics of familial cases from multiple branches of a large consanguineous family with cerebellar ataxia, mental retardation (MR), and dysequilibrium syndrome type 3 caused by a mutation in the recently cloned CA8 gene. The linkage analysis revealed a high logarithm of the odds (LOD) score region on 8q that harbors the CA8 in which a novel homozygous c.484G>A (p.G162R) mutation was identified in all seven affected members. The patients had variable cerebellar ataxia and mild cognitive impairment without quadrupedal gait. The brain MRI showed variable cerebellar volume loss and ill-defined peritrigonal white matter abnormalities. The Fluorodeoxyglucose Positron Emission Tomography (FDG PET) revealed hypometabolic cerebellar hemispheres, temporal lobes, and mesial cortex. This report expands the neurological and radiological phenotype associated with CA8 mutations. CA8 involvement should be considered in the differential diagnosis of other genetically unresolved autosomal recessive cerebellar ataxias.