This is the first trio-based WGS study for nanophthalmos, revealing the potential role of DNMs in MYRF and rare inherited genetic variants in PRSS56 and MFRP.
The membrane frizzled-related protein (MFRP) gene is involved in axial length (AL) regulation and MFRP mutations cause nanophthalmos; also, the hepatocyte growth factor (HGF) gene is reported to result in morphologic changes of the anterior segment and abnormal aqueous regulation that increases the risk of primary angle-closure glaucoma (PACG), while the zinc ring finger 3 (ZNRF3) gene is associated with AL.
Hyperopia (farsightedness) is a common and significant cause of visual impairment, and extreme hyperopia (nanophthalmos) is a consequence of loss-of-function MFRP mutations.
Mutations in MFRP have been reported to cause autosomal recessive posterior microphthalmia, nanophthalmos, and an ophthalmic syndrome characterized by posterior microphthalmia, high hyperopia, retinitis pigmentosa, foveoschisis, and optic disc drusen.
Mutations in the membrane frizzled-related protein (MFRP/Mfrp) gene, specifically expressed in the retinal pigment epithelium (RPE) and ciliary body, cause nanophthalmia or posterior microphthalmia with retinitis pigmentosa in humans, and photoreceptor degeneration in mice.
Mutations in the membrane-type frizzled-related protein (MFRP) gene have been identified in patients with pathologic high hyperopia associated with nanophthalmos or microphthalmia.
To identify the disease-causing defect in these families, we first analysed MFRP gene, then some candidate genes (CHX10, OPA1, MITF, SOX2, CRYBB1-3 and CRYBA4) and loci (MCOP1, NNO1 and NNO2) previously implicated in different forms of microphthalmia.
The membrane frizzled-related protein (MFRP) has been proposed as a probable candidate gene for extreme hyperopia and nanophthalmos, which are factors for angle-closure glaucoma.