CCDC66 mutations are associated with high myopia through affected cell mitosis

Area of Science:

• Genetics
• Ophthalmology
• Molecular Biology

Background:

• High myopia (HM) is a refractive error exceeding -5.00 D, increasing blindness risk.
• The genetic basis and mechanisms of HM are not fully understood.
• Identifying novel causative genes is crucial for understanding HM pathogenesis.

Purpose of the Study:

• To identify the causal gene in a family with high myopia.
• To investigate the role of the identified gene in HM development.
• To explore the functional impact of gene mutations on retinal cells.

Main Methods:

• Exome and Sanger sequencing to identify and confirm gene mutations.
• Single-cell RNA sequencing to analyze gene expression in developing retinas.
• CRISPR/Cas9 gene editing and cell-based assays (immunofluorescence, immunoblot) to study gene function.

Main Results:

• A nonsense mutation (c.C172T, p.Q58X) in the CCDC66 gene co-segregated with HM in a family.
• Six additional rare CCDC66 variants were found in sporadic HM cases.
• CCDC66 deficiency impaired cell proliferation and microtubule polymerization, and mutated CCDC66 disrupted mitosis.

Conclusions:

• The CCDC66 variant c.C172T is associated with high myopia.
• CCDC66 deficiency may disrupt retinal cell proliferation and mitosis, contributing to HM.
• CCDC66 is a potential novel gene involved in the pathogenesis of high myopia.