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Childhood absence epilepsy (CAE) accounts for 10% to 12% of epilepsy in children under 16 years of age. We screened for mutations in the GABA(A) receptor (GABAR) beta 3 subunit gene (GABRB3) in 48 probands and families with remitting CAE. We found that four out of 48 families (8%) had mutations in GABRB3. One heterozygous missense mutation (P11S) in exon 1a segregated with four CAE-affected persons in one multiplex, two-generation Mexican family. P11S was also found in a singleton from Mexico. Another heterozygous missense mutation (S15F) was present in a singleton from Honduras. An exon 2 heterozygous missense mutation (G32R) was present in two CAE-affected persons and two persons affected with EEG-recorded spike and/or sharp wave in a two-generation Honduran family. All mutations were absent in 630 controls. We studied functions and possible pathogenicity by expressing mutations in HeLa cells with the use of Western blots and an in vitro translation and translocation system. Expression levels did not differ from those of controls, but all mutations showed hyperglycosylation in the in vitro translation and translocation system with canine microsomes. Functional analysis of human GABA(A) receptors (alpha 1 beta 3-v2 gamma 2S, alpha 1 beta 3-v2[P11S]gamma 2S, alpha 1 beta 3-v2[S15F]gamma 2S, and alpha 1 beta 3-v2[G32R]gamma 2S) transiently expressed in HEK293T cells with the use of rapid agonist application showed that each amino acid transversion in the beta 3-v2 subunit (P11S, S15F, and G32R) reduced GABA-evoked current density from whole cells. Mutated beta 3 subunit protein could thus cause absence seizures through a gain in glycosylation of mutated exon 1a and exon 2, affecting maturation and trafficking of GABAR from endoplasmic reticulum to cell surface and resulting in reduced GABA-evoked currents.

Purpose: To review the clinical and neuroimaging features of a large series of patients with Sturge-Weber syndrome (SWS) seen over a 40-year period. Methods: Fifty-five patients with SWS (30 males and 25 females), were studied between 1965 and 2004. Results of neurological and ophthalmological examinations, electroencephalographic, and neuroimaging studies were reviewed. All patients were seen by one of the authors (I. P-C). Results: Epilepsy, hemiparesis, mental retardation and ocular problems were the most frequent and severe features of patients with Sturge-Weber syndrome in this series. The facial nevus flammeus was unilateral in 35 (63.5%) patients, bilateral in 17 (31%) and absent in 3 (5.5%) of the patients with leptomeningeal angiomas. Seven (41%) of the 17 patients with bilateral nevus flammeus had unilateral leptomeningeal angiomas. Seizures occurred in 47 patients (85.5%). Complete seizure control was obtained in 20 patients (42.5%), but in 2 of these 20 patients seizures were controlled only after lobectomy. All patients with unilateral or bilateral upper eyelid nevus flammeus had ipsilateral, unilateral or bilateral choroid-retinal angiomas. Only 20 (36%) of the 55 patients had low-normal or borderline intelligence (IQs<70). No relationship was observed between the size of the facial nevus flammeus and the severity of the brain lesion. Conclusions: Epilepsy, hemiparesis, mental retardation and ocular problems were the most frequent and severe features of patients with Sturge-Weber syndrome in this series. Cerebral lesions followed a progressive course during early childhood, but not later. Early surgical treatment controlled the seizures but other neurological problems such as hemiparesis and intellectual deficits showed a less satisfactory response. Early onset of seizures and poor response to medical treatment, bilateral cerebral involvement and unilateral severe lesions were indicative of a poor prognosis. Limited intelligence and social skills, poor aesthetic appearance and seizures complicated the integration of SWS patients. These features must be addressed in order for the patients improve social interactions, obtain gainful employment and achieve a better quality of life. Tous les patients ont été examinés par un des auteurs (I.P -C). Résultats : Les manifestations les plus fréquentes et les plus sévères chez les patients atteints du SSW dans cette série de cas étaient l'épilepsie, l'hémiparésie, le retard mental et les problèmes oculaires. Le naevus flammeus facial était unilatéral chez 35 patients (63,5%) atteints d'angiomes des leptoméninges, bilatéral chez 17 patients (31%) et absent chez 3 patients (5,5%). Sept patients (41%) parmi les 17 patients atteints de naevus flammeus bilatéral avaient des angiomes leptoméningés unilatéraux. Quarante-sept patients (85,5%) présentaient des crises convulsives. Un contrôle absolu des crises a été obtenu chez 20 patients (42,5%). Cependant, chez 2 de ces patients les crises ont été contrôlées seulement après une lobectomie. Tous les patient...

L-2-Hydroxyglutaric aciduria (L2HGA) is a rare, neurometabolic disorder with an autosomal recessive mode of inheritance. Affected individuals only have neurological manifestations, including psychomotor retardation, cerebellar ataxia, and more variably macrocephaly, or epilepsy. The diagnosis of L2HGA can be made based on magnetic resonance imaging (MRI), biochemical analysis, and mutational analysis of L2HGDH. About 200 patients with elevated concentrations of 2-hydroxyglutarate (2HG) in the urine were referred for chiral determination of 2HG and L2HGDH mutational analysis. All patients with increased L2HG (n 5 106; 83 families) were included. Clinical information on 61 patients was obtained via questionnaires. In 82 families the mutations were detected by direct sequence analysis and/or multiplex ligation dependent probe amplification (MLPA), including one case where MLPA was essential to detect the second allele. In another case RT-PCR followed by deep intronic sequencing was needed to detect the mutation. Thirty-five novel mutations as well as 35 reported mutations and 14 nondiseaserelated variants are reviewed and included in a novel Leiden Open source Variation Database (LOVD) for L2HGDH variants (http://www.LOVD.nl/L2HGDH). Every user can access the database and submit variants/ patients. Furthermore, we report on the phenotype, including neurological manifestations and urinary levels of L2HG, and we evaluate the phenotype-genotype relationship.

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Joubert Syndrome Related Disorders (JSRDs) are autosomal recessive pleiotropic conditions sharing a peculiar cerebellar and brainstem malformation known as the "molar tooth sign" (MTS). Recently, mutations in a novel ciliary gene, RPGRIP1L, have been shown to cause both JSRDs and MeckelGruber syndrome. We searched for RPGRIP1L mutations in 120 patients with proven MTS and phenotypes representative of all JSRD clinical subgroups. Two homozygous mutations, the previously reported p.T615P in exon 15 and the novel c.2268_2269delA in exon 16, were detected in two out of 16 families with cerebello-renal presentation (~12%). Conversely, no pathogenic changes were found in patients with other JSRD phenotypes, suggesting that RPGRIP1L mutations are largely confined to the cerebello-renal subgroup, while they overall represent a rare cause of JSRD (<2%).

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