Molecular genetic of Oguchi dieae, fundu albipunctatu, and other form of tationary night blindne: LVII Edward Jackon Memorial Lecture

PURPOE: To compare the clinical finding of the variou form of tationary night blindne caued by mutation in identified gene encoding protein of photoreceptor or the retinal pigment epithelium. METHOD: Review of the viual acuitie, viual field, fundi, dark-adaptation curve, and electroretinogram from patient with tationary night blindne caued by mutation in the gene RHO, GNAT1, PDE6B, RHOK, AG, RDH5, and CACNA1F, repectively encoding rhodopin, the α ubunit of rod tranducin, the β ubunit of rod cGMP-phophodieterae, rhodopin kinae, arretin, 11-ci retinol dehydrogenae, and a retinal L-type calcium channel. REULT: In the evaluated form of tationary night blindne, the time coure of dark adaptation and the characteritic of the electroretinogram indicate that rod photoreceptor are preent and that they function, although abnormally. In night blindne reulting from defect in rhodopin, the α ubunit of rod tranducin, or the β ubunit of rod cGMP phophodieterae, rod photoreceptor repond only to light intenitie far brighter than normal, and the enitivity of rod to light i imilar to that of normal individual who are not dark adapted. In fundu albipunctatu and in Oguchi dieae, the rod photoreceptor can achieve normal enitivity to dim light but only after 2 or more hour of dark adaptation, compared with approximately 0.5 hour for normal individual. In each of thee form of tationary night blindne, the poor rod enitivity and the time coure of dark adaptation correlate with the known or preumed phyiologic abnormalitie caued by the identified gene defect. Patient with ome form of tationary night blindne, uch a fundu albipunctatu and Oguchi dieae, may develop degeneration of the retina leading to evere lo of viion in later life. CONCLUION: The identification of the mutant gene cauing form of tationary night blindne refine the claification of thee dieae and enhance our undertanding of the underlying phyiologic defect. Ophthalmologit mut be aware that although thee dieae are traditionally categorized a “tationary,” ome of them lead to reduced viual acuity or contricted viual field, epecially in older patient. Effort to develop therapie for thee dieae hould concentrate on thee more evere form.