However, two subsequent studies on Caucasian POAG patients, one study involving 801 patients of variable age onset [23] and one involving 86 adult-onset patients [24], found no glaucoma-causing mutations in OPTN. In Japan, 148 patients with NTG and 165 with hypertension glaucoma had no specific glaucoma-causing mutations in OPTN [25]. Here, OPTN is linked to hypertensive disorder.