Congenital stationary night blindness 1C

It belongs to a group of clinically heterogeneous retinal disorders in which genes involved in the response to light of the cells that make up the retina are involved.

Congenital congenital stationary night blindness (CSNB) refers to a group of rare, clinically heterogeneous, nonprogressive retinal disorders that appear during childhood. The genes involved in the different forms of CSNB encode proteins involved in the phototransduction cascade that are important in retinal signaling from photoreceptors (cones and rods) to adjacent nerve cells.

Congenital stationary night blindness may be caused by defects in up to 17 genes, including TRPM1, which is affected in CSNB type 1C.

Symptoms

Patients with congenital stationary night blindness show a characteristic electroretinogram (ERG). This type of ERG (called Schubert-Bornschein) allows discrimination of two subtypes of CSNB: incomplete and complete. The incomplete type is characterized by a substantially reduced rod and cone photoreceptor response due to dysfunction of ON and OFF bipolar cells.The complete type, as in the case of TRPM1-associated CSNB, results in drastically reduced rod photoreceptor response, but with a largely normal cone response due to ON bipolar cell dysfunction.

It has been observed that TRPM1 gene-associated CSNB may be related to high levels of myopia in preschool children.

Disease management

No treatment is currently available.

Genes analyzed

TRPM1

Bibliography

Almutairi F, Almeshari N, Ahmad K, et al . Congenital stationary stationary night blindness: an update and review of the disease spectrum in Saudi Arabia. Acta Ophthalmol. 2021 Sep;99(6):581-591.

Audo I, Kohl S, Leroy BP, et al . TRPM1 is mutated in patients with autosomal-recessive complete congenital stationary stationary night blindness. Am J Hum Genet. 2009 Nov;85(5):720-9.

Carss KJ, Arno G, Erwood M, et al . Comprehensive Rare Variant Analysis via Whole-Genome Sequencing to Determine the Molecular Pathology of Inherited Retinal Disease. Am J Hum Genet. 2017 Jan 5;100(1):75-90.

van Genderen MM, Bijveld MM, Claassen YB, et al . Mutations in TRPM1 are a common cause of complete congenital stationary stationary night blindness. Am J Hum Genet. 2009 Nov;85(5):730-6.