The spacer sequence between the palindromic motifs is constant in length, but its sequence is highly variable among viral species, presenting a relaxed consensus (TT)GGKCCCY, which is similar to the Conserved Late Element or CLE (GTGGTCCC), a putative TrAP-responsive element.
The typical MRI pattern with a diffuse CSF-like aspect of the cerebral white matter can lack particularly in the adult forms whereas an increasing number of patients with clinical and MRI criteria for CACH/VWM disease but without eIF2B mutations are found.
Vanishing white matter disease (VWM; MIM #603896), also known as childhood ataxia with central nervous system hypomyelination (CACH) syndrome, is an autosomal recessive transmitted leukoencephalopathy related to mutations in each of the 5 genes (EIF2B1, EIF2B2, EIF2B3, EIF2B4 and EIF2B5) encoding for the 5 subunits of eukaryotic translation initiation factor 2B (eIF2B), essential for protein synthesis.
We are reporting on a patient with infantile onset VWM associated with three heterozygous missense variants in EIF2B5, including a novel missense variant on exon 6 of EIF2B5 (D262N), as well as an interstitial duplication at 7q21.12.
Whole-exome sequencing identified two heterozygous mutations in the EIF2B5 gene: a known mutation, c.584G>A (R195H, which is homozygous in CLE), and a novel mutation, c.1223T>C (I408T, which resides in the "I-patch").