Similarities and differences between infantile and early childhood onset vanishing white matter disease

EIF2B2 gene mutation causing early onset vanishing white matter disease: a case report

Background

Leukoencephalopathy with vanishing white matter (VWM) is an autosomal recessive neurological disease. The physiopathology of disease is still little understood, but it seems to involve impairment in maturation of astrocytes; as a consequence white matter is more prone to cellular stress. Disease is caused by mutations in five genes encoding subunits of the translation initiation factor eIF2B. We know five different types of VWM syndrome classified based different ages of onset (prenatal, infantile, childhood, juvenile and adult onset).

Case presentation

We report the case of a 4-month-old boy with early seizure onset, recurrent hypoglycemia and post mortem diagnosis of vanishing white matter disease (VMD). At the admission he presented suspected critical episodes, resolved after intravenous administration of benzodiazepines. The brain MRI showed total absence of myelination that suggested hypomyelination leukoencephalopathy. The whole exome sequencing (WES) revealed a variant of EIF2B2 gene (p. Val308Met) present in homozygosity. In this case report we also describe the clinical evolution of seizures, in fact the epileptic seizures had a polymorphic aspect, from several complex partial seizures secondarily generalized to status epilepticus.

Conclusion

Infantile and early childhood onset forms are associated with chronic progressive neurological signs, with episodes of rapid neurological worsening, and poor prognosis, with death in few months or years. Clinical presentation of epilepsy is poorly documented and do not include detailed information about the type, time of onset and severity of seizures. No therapeutic strategies for VWM disease have been reported.

In vivo targeting of a variant causing vanishing white matter using CRISPR/Cas9

Vanishing white matter (VWM) is a leukodystrophy caused by recessive variants in subunits of eIF2B. At present, no curative treatment is available and patients often die at young age. Due to its monogenic nature, VWM is a promising candidate for the development of CRISPR/Cas9-mediated gene therapy. Here we tested a dual-AAV approach in VWM mice encoding CRISPR/Cas9 and a DNA donor template to correct a pathogenic variant in Eif2b5. We performed sequencing analysis to assess gene correction rates and examined effects on the VWM phenotype, including motor behavior. Sequence analysis demonstrated that over 90% of CRISPR/Cas9-induced edits at the targeted locus are insertion or deletion (indel) mutations, rather than precise corrections from the DNA donor template by homology-directed repair. Around half of the CRISPR/Cas9-treated animals died prematurely. VWM mice showed no improvement in motor skills, weight, or neurological scores at 7 months of age, and CRISPR/Cas9-treated controls displayed an induced VWM phenotype. In conclusion, CRISPR/Cas9-induced DNA double-strand breaks (DSBs) at the Eif2b5 locus did not lead to sufficient correction of the VWM variant. Moreover, indel formation in Eif2b5 induced an exacerbated VWM phenotype. Therefore, DSB-independent strategies like base- or prime editing might better suited for VWM correction.

Profile of Indian Children with Childhood Ataxia and Central Nervous System Hypomyelination/Vanishing White Matter Disease: A Single Center Experience from Southern India

Background  Childhood ataxia with central nervous system hypomyelination (CACH) is a recently described childhood inherited white matter disease, caused by mutations in any of the five genes encoding eukaryotic translation initiation factor ( eIF2B ). Methods  Retrospective review of the charts of children with CACH was performed from January 2014 to March 2020 at tertiary care center from Southern India. Diagnosis was based on magnetic resonance imaging (MRI) criteria or genetic testing. Results  Total number of children with CACH enrolled were 18. Male/female ratio was 10:8. Mean age of presentation was 37.11 months (range =  6-144 months). Affected siblings were seen in five (28%) cases. All children had spasticity, ataxia, and diffuse white matter changes with similar signal as cerebrospinal fluid on all pulse sequences on MRI brain. Of the 18 children, only nine are alive. Duration of illness among deceased children was 9.6667 months (range = 2-16 months). Waxing and waning of symptoms were seen in seven cases. Genetic analysis of EIF2B gene was performed in five cases, among which three mutations were novel. Conclusion  A diagnosis of childhood ataxia with central nervous system hypomyelination should be considered in patients presenting with acute onset neuroregression following infection or trauma with associated neuroimaging showing classical white matter findings.

CT and MRI findings in infantile vanishing white matter

Infantile vanishing white matter disease is an uncommon cause of developmental delay and seizures in children. Presented here is a case of vanishing white matter disease diagnosed at 6 months of age. Imaging findings demonstrated widespread white matter abnormalities throughout the supratentorial and infratentorial brain. The diagnosis of infantile vanishing white matter disease was confirmed via molecular analysis which revealed a rare mutation in the gene responsible for this disorder.

Vanishing white matter disease with different faces

PURPOSE

The goal of this study was to better understand vanishing white matter (VWM) disease, which is one of the most common hereditary white matter disorders, and its relationship to radiologic features, genetic analyses, and clinical findings.

METHODS

We performed a study on 11 patients to describe the clinical and neuroimaging features of VWM. Patients were grouped into "infantile," "early childhood," and "juvenile" based on their onset age. EIF2B1-5 genes encoding five subunits of eukaryotic translation initiation factor 2B (eIF2B) were analyzed in all patients with clinically suspected VWM disease.

RESULTS

In brain magnetic resonance imaging (MRI), all patients showed white matter abnormalities with various degrees. The initial clinical presentation in five of patients was ataxia, with severe refractory epilepsy in three patients. In children with infantile-onset VWM, a rapid deterioration of motor function was detected, and the frequency of epilepsy was higher. Two patients showed manifestations of end-stage VWM disease, and one of them had chronic subdural hematoma. One of our patients and his father were diagnosed with Brugada syndrome. Sequencing of the exons and exon-intron boundaries of the EIF2B1-5 genes revealed mutations in the genes EIF2B5 (5 cases), EIF2B3 (3 cases), and EIF2B4 (2 cases). We also found a novel mutation in one patient: c.323_325delGAA in the EIF2B1 gene.

CONCLUSIONS

In this study, in addition to classical clinical and radiological findings, we wanted to emphasize that we may be confronted with refractory epilepsy (early infancy), cardiac problems, and intracranial complications that may occur in advanced stages.