Chromosome 4 Open Reading Frame 6 (C4orf6)

In a consanguineous pedigree diagnosed with EvC and borderline intelligence, A 520-kb homozygous deletion comprising EVC, EVC2, C4orf6, and STK32B, caused by recombination between long interspersed nuclear element-1 (LINE-1 or L1) elements. Patients homozygous for the deletion are deficient in EVC and EVC2 and have no increase in the severity of the EvC typical features. Similarly deletion carriers demonstrate absence of digenic inheritance in EvC. Further, the phenotype of these patients suggests that the EVC-STK32B deletion also leads to mild mental retardation and reveals that loss of the novel genes C4orf6 and STK32B causes at most mild mental deficit. These findings highlight the importance of L1 repetitive sequences in human genome architecture and disease.