Novel homozygous nonsynonymous variant of CNNM4 gene in a Chinese family with Jalili syndrome.

Background: Jalili syndrome (JS) is a rare autosomal-recessive inherited disorder characterized by cone-rod dystrophy and amelogenesis imperfecta. It is often misdiagnosed in clinical practice due to its heterogeneity and rarity.

Methods: Two JS patients from a consanguineous family were included in this study. Detailed ophthalmic examinations were performed. Oral photography was taken. The DNA sample of the proband was sequenced using the customized capture panel, which includes 338 retinal disease genes. Sanger sequencing was performed for validation and segregation.

Results: The patients had poor vision, photophobia, and nystagmus from childhood. Fundus examination revealed diffused chorioretinal atrophy with a prominent macular coloboma. OCT showed a deep staphyloma, severely reduced retinal thickness, retinoschisis, loss of photoreceptor layer, and retinal pigment epithelium in the macular region. Amelogenesis imperfecta, dental decay, staining, irregular shapes, and loss of teeth were present. Next-generation sequencing combined with Sanger validation identified a novel homozygous nonsynonymous variant c.598T>C (p.S200P) in CNNM4 gene (NM_020184.3).

Conclusions: We described the clinical features of a Chinese family with JS and identified a novel disease-causing mutation. Our findings broadened the phenotypes and mutation spectrums of JS in Chinese population, as well as are helpful in the diagnosis of this rare disease.