In addition to uncovering likely disease-causing variants, we identified 5 families with single deleterious variants in recessive genes PRSS56 and MFRP. In families with biallelic MFRP pathogenic variants, heterozygous carriers have a normal axial length and refraction both in our study (F1 for example) and previously15, suggesting that these patients with single deleterious alleles in MFRP either have an additional regulatory or deep intronic mutation or another genetic cause for their nanophthalmos. This evidence concerns the gene MFRP and microphthalmia.