Posterior staphyloma with congenital stationary night blindness

Posterior staphyloma, typically found in highly myopic eyes, may rarely be present in the absence of high myopia, in the context of various inherited degenerative diseases such as rod-cone dystrophy, Leber’s congenital amaurosis or retinitis pigmentosa. However, to our knowledge, the association between posterior staphyloma without high myopia and congenital stationary night blindness (CSNB) has never been described in the literature. CSNB is a genetically and clinically heterogenous retinal disorder, and it can be inherited in an autosomal dominant (AD), recessive (AR) or X-linked (XL) mode. Over 360 variants involving 17 genes, which affects signal processing within photoreceptors, retinoid recycling in the retinal pigment epithelium (RPE) and signal transmission via retinal bipolar cells have been associated with CSNB. CSNB is characterized by a nonprogressive nyctalopia, not always described (notably in children), a variable decrease in visual acuity (especially in the autosomal recessive and X-linked modes), and myopia. In addition, in autosomal recessive and X-linked forms, CSNB is also often associated with strabismus and nystagmus. Furthermore, CSNB is classified as being complete or incomplete, depending on the extent to which an electronegative electroretinogram is observed. This electro-physiologic presentation, as well as the mode of inheritance, are associated with specific mutated genes. For instance, the TRPM1 gene, which is mutated in this case, is affected in the autosomal recessive complete CSNB. This case aims at describing the clinical presentation of the homozygous variant c.1730A > T in the TRPM1 gene. To the best of our knowledge, this is the first description in the literature of this variant.