Unravelling the molecular complexity behind ocular maldevelopment (360G-Wellcome-205174_Z_16_Z)

Aim: Investigating the relationship between genotype, gene expression and phenotype of microphthalmia, anophthalmia and ocular coloboma (MAC), which collectively causes one-third of life-long blindness and severe visual impairment in children worldwide. Research questions: What are the pathogenic variants underlying MAC? How do molecular subtypes correlate with phenotype and stratify clinical risk? What molecular pathways are involved in human eye development? What is the relationship between genotype and gene expression in microphthalmia? Key goals and methodology: Whole genome sequencing of 30 parent-offspring trios with isolated MAC and longitudinal phenotyping. Establish an international reference network to stratify a well-defined cohort to improve care pathways and future research. Temporal comparative analysis of DNA methylome (bisulfite conversion and Illumina Infinium EPIC BeadChips) and transcriptome (65 million reads per sample using Illumina HiSeq-2500) in the developing human eye between 4-9 weeks gestation. Model 3D human microphthalmic optic cups using iPSC technology with isogenic controls using CRISPR/Cas9 gene-editing. DNA methylome and transcriptome analysis to assess disruption of molecular pathways. Outcomes: Establish a molecular framework for ocular maldevelopment. Identify drug targets and develop therapeutics. Improve genetic diagnosis, counselling and management. Elucidate shared molecular mechanisms between embryonic tissue fusion defects and late-onset visual sensory disorders.