Nonarteritic Anterior Ischemic Optic Neuropathy, Susceptibility To

A number sign (#) is used with this entry because a polymorphism of the gene encoding glycoprotein Ib-alpha (GP1BA; 606672) confers susceptibility to nonarteritic anterior ischemic optic neuropathy.

Clinical Features

Deutsch et al. (1990) described a family in which identical twin sisters in their forties had bilateral nonarteritic anterior ischemic optic neuropathy (NAION) and a younger sister had unilateral papillophlebitis. Berggren et al. (1974) had reported 3 of 7 sibs with anterior ischemic optic neuropathy; in 2, the involvement was bilateral and in 1 unilateral.

Mojon et al. (2002) found a high prevalence of sleep apnea syndrome (107650) in patients with NAION, which supported previous case reports suggesting that such an association existed. This association might explain why approximately 75% of all patients with NAION discovered visual loss upon first awakening or when they first used vision critically after sleeping. The authors stated that sleep apnea syndrome may play an important role in the pathogenesis of NAION.

Deramo et al. (2003) investigated the relationship between NAION and serum lipid levels in 37 consecutive patients diagnosed with NAION at or below age 50 years and 74 age- and gender-matched controls. They found that hypercholesterolemia (143890) was a risk factor in these patients and suggested that NAION might be the first manifestation of a previously unrecognized lipid disorder. The patients had experienced a focal, microvascular central nervous system ischemic event at a relatively young age. Deramo et al. (2003) suggested that aggressive treatment of lipid abnormalities might be warranted in these patients.

Purvin et al. (2004) reviewed medical records of 20 patients who experienced an episode of NAION in an eye with optic disc drusen (ODD). The authors found that their patients were strikingly similar to those with NAION unassociated with drusen with regard to prevalence of vascular risk factors, pattern of visual field loss, and occurrence of a subsequent similar event in the other eye. In contrast, however, patients with ODD and NAION were younger than those with NAION, were more likely to report preceding episodes of transient visual obscuration, and had a more favorable visual outcome.

Molecular Genetics

Salomon et al. (2004) reported that the presence of the VNTR B allele of the GP1BA gene (606672.0002) confers a significant risk for NAION and predisposed affected patients to second eye involvement.