Discussion
We reviewed the ocular phenotypes reported in 74 individuals with PACS1-related NDD and the overlaps with WDR37- and PACS2-related syndromes. We found that the 3 syndromes have in common the presence of colobomata, ptosis, nystagmus, strabismus, and refractive errors, whereas microphthalmia, microcornea, and Peters anomaly are found only among individuals with PACS1-related NDD and WDR37 syndrome, being more severe in the latter. This supports the previous statement that the so-called WDR37-PACS1-PACS2 axis might have an important role in ocular development and also that the specific ocular findings could be useful in the clinical differentiation between these related syndromes.