Congenital stationary night blindness 1C
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.
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.
No treatment is currently available.