PGAP1 and Cerebral visual impairment: In a retrospective study, 7% of a well-characterised CVI cohort had at least one clinically significant chromosomal abnormality.12 Building on this finding of a high genomic diagnostic yield, trio exome sequencing was carried out for 25 cases of idiopathic CVI, which identified a definite or potential genetic aetiology in 16 individuals.13 Variants were found in four genes previously associated with CVI (AHDC1, NGLY1, NR2F1 and PGAP1) and 19 further candidate genes.