Eukaryotic initiation factor 2B (eIF2B)-related disorders are heritable white matter disorders with a variable clinical phenotype (including vanishing white matter disease and ovarioleukodystrophy) and an equally heterogeneous genotype. We report 9 novel mutations in the EIF2B genes in our subject population, increasing the number of known mutations to more than 120. Using homology modeling, we have analyzed the impact of novel mutations on the 5 subunits of the eIF2B protein. Although recurrent mutations have been found at CpG dinucleotides in the EIF2B genes, the high incidence of private or low frequency mutations increases the challenge of providing rapid genetic confirmation of this disorder, and limits the application of EIF2B screening in cases of undiagnosed leukodystrophy.
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"It was described by Van der Knaap and colleagues in 1996 after the finding of cystic degeneration of the cerebral white matter in the necropsy of nine patients. Some case reports in the 1960s and 1970s might correspond to this disease.1,7,21,22 "
[Show abstract][Hide abstract] ABSTRACT: Vanishing white matter (VWM) leukoencephalopathy is one of the most prevalent hereditary white matter diseases. It has been associated with mutations in genes encoding eukaryotic translation initiation factor (eIF2B). We have compiled a list of all the patients diagnosed with VWM in Spain; we found 21 children. The first clinical manifestation in all of them was spasticity, with severe ataxia in six patients, hemiparesis in one child, and dystonic movements in another. They suffered from progressive cognitive deterioration and nine of them had epilepsy too. In four children, we observed optic atrophy and three also had progressive macrocephaly, which is not common in VWM disease. The first two cases were diagnosed before the 1980s. Therefore, they were diagnosed by necropsy studies. The last 16 patients were diagnosed according to genetics: we found mutations in the genes eIF2B5 (13 cases), eIF2B3 (2 cases), and eIF2B4 (1 case). In our report, the second mutation in frequency was c.318A>T; patients with this mutation all followed a slow chronic course, both in homozygous and heterozygous states. Previously, there were no other reports to confirm this fact. We also found some mutations not described in previous reports: c.1090C>T in eIF2B4, c.314A>G in eIF2B5, and c.877C>T in eIF2B5.
Full-text · Article · Jul 2014 · Journal of Central Nervous System Disease
[Show abstract][Hide abstract] ABSTRACT: We compared epilepsy phenotypes with genotypes of Angelman syndrome (AS), including chromosome 15q11-13 deletions (class I), uniparental disomy (class II), methylation imprinting abnormalities (class III), and mutation in the UBE3A gene (class IV). Twenty patients were prospectively selected based on clinical cytogenetic and molecular diagnosis of AS. All patients had 6 to 72 hours of closed-circuit television videotaping and digitized electroencephalogrpahic (EEG) telemetry. Patients from all genotypic classes had characteristic EEGs with diffuse bifrontally dominant high-amplitude 1- to 3-Hz notched or triphasic or polyphasic slow waves, or slow and sharp waves. Class I patients had severe intractable epilepsy, most frequently with atypical absences and myoclonias and less frequently with generalized extensor tonic seizures or flexor spasms. Epileptic spasms were recorded in AS patients as old as 41 years. Aged-matched class II, III, and IV patients had either no epilepsy or drug-responsive mild epilepsy with relatively infrequent atypical absences, myoclonias, or atonic seizures. In conclusion, maternally inherited chromosome 15q11-13 deletions produce severe epilepsy. Loss-of-function UBE3A mutations, uniparental disomy, or methylation imprint abnormalities in AS are associated with relatively mild epilepsy. Involvement of other genes in the chromosome 15q11-13 deletion, such as GABRB3, may explain severe epilepsy in AS.
Full-text · Article · Apr 1998 · Annals of Neurology
[Show abstract][Hide abstract] ABSTRACT: Vanishing white matter (VWM) disease, inherited in an autosomal recessive manner, is one of the most prevalent inherited leukoencephalopathies in childhood. It is a hereditary human disease resulting from the direct defects during protein synthesis, with the gene defects in EIF2B1-5 (identified in 2001-2002) encoding the five subunits of eukaryotic translation initiation factor (eIF2B alpha, beta, gamma, delta and epsilon), respectively. Most of the published studies were carried out in the white population. The analysis of clinical features and EIF2B mutation screening were performed in 11 Chinese patients for the first time. Mutations were identified exclusively in EIF2B5 and EIF2B3 in these patients, with six novel mutations, including five missense mutations (EIF2B5: c.185A>T, p.D62V; c.1004G>C, p.C335S; c.1126A>G, p.N376D; EIF2B3: c.140G>A, p.G47E; c.1037T>C, p.I346T) and one deletion leading to amino-acid deletion (EIF2B5: c.1827-1838del, p.S610-D613del). EIF2B3 mutation, accounting for 20% of the total number of mutations found in this study, is more prevalent than expected according to an earlier report (7%). A hot spot mutation in EIF2B3 was identified in this study. A unique EIF2B mutation spectrum in Chinese VWM patients was shown. A systemic study to assess mutation spectrum in different populations needs to be carried out.
No preview · Article · Jan 2009 · Journal of Human Genetics