As the function of the nyctalopin protein is unknown, these mutations have not been further characterized. However, many of them are predicted to lead to truncated proteins that, presumably, are non-functional. CSNB2
The incomplete form of X-linked congenital stationary night blindness (CSNB2) is caused by mutations in the CACNA1F gene, which encodes the voltage-gated calcium channel CaV1.4 expressed heavily in retina. One of the important properties of this channel is that it inactivates at an extremely low rate. This allows it to produce sustained Ca2+ entry upon depolarization. As photoreceptors  depolarize in the absence of light, CaV1.4 channels operate to provide sustained neurotransmitter release upon depolarization. This has been demonstrated in CACNA1F mutant mice that have markedly reduced photoreceptor calcium signals. There are currently 55 mutations in CACNA1F located throughout the channel, Table 2 and Figure 1. While most of these mutations result in truncated and, likely, non-functional channels, it is expected that they prevent the ability of light to hyperpolarize photoreceptors. Of the mutations with known functional consequences, 4 produce channels that are either completely non-functional, and two that result in channels which open at far more hyperpolarized potentials than wild-type. This will result in photoreceptors that continue to release neurotransmitter even after light-induced hyperpolarization. Diagnosis
Footnotes
External links

GeneReview/NCBI/NIH/UW entry on X-Linked Congenital Stationary Night Blindness
A new paper was published on these findings and MedCo filed for a new patent for the drug as a treatment for heart failure specifically in black patients.The new patent and the old patent were then licensed to a company called NitroMed, which ran a clinical called the African-American Heart Failure Trial (A-HeFT), the results of which were published in 2004 in the New England Journal of Medicine. The clinical trial was stopped early because the drug showed significant benefit; it reduced mortality by 43%, reduced hospitalizations by 39%, and improved quality of life markers in African-American patients with CHF.On the basis of A-HeFT, the FDA approved BiDil in June 2005. In 2006, the Heart Failure Society of America included the use of the fixed dose combination of isosorbide dinitrate/hydralazine as the standard of care in the treatment of heart failure in blacks. : e44

Society and culture
Controversy
The new drug application claiming treatment of a single, self-identified racial group raised a storm of controversy.