Eye Movement Abnormalities in Hermansky-Pudlak Syndrome

Clinical and Oculomotor Characteristics of Albinism Compared toFRMD7Associated Infantile Nystagmus

“…Abadi and Dickinson 10 found strabismus in 90.5% of albinos compared with 37.1% in subjects with infantile nystagmus due to various other causes including IIN. Gradstein et al 28 found strabismus in 74% of subjects with HermanskyPudlack syndrome, a form of oculocutaneous albinism. The prevalence of strabismus found in patients with FRMD7 mutation was 7.8% 6 and 44%.…”

Visual rehabilitation of patients with oculocutaneous albinism Type I (OCA1): Results in 85 patents

“…About 9% to 33% of patients with INS will have an inherent, rhythmic, periodic or aperiodically changing nystagmus intensity and/or direction over time. Most clinicians are familiar with this oscillation as acquired periodic alternating nystagmus (PAN) [11][12][13][14][15][16]44]. Acquired PAN has a specific pattern identified by the presence of spontaneous nystagmus in the primary position, which beats horizontally in one direction for 1 or 2 minutes, followed by a quiet period, and then reappearance of the nystagmus in the opposite direction for a similar length of time.…”

“…Acquired PAN has a specific pattern identified by the presence of spontaneous nystagmus in the primary position, which beats horizontally in one direction for 1 or 2 minutes, followed by a quiet period, and then reappearance of the nystagmus in the opposite direction for a similar length of time. Acquired PAN can also occur in association with midbrain or cerebellar disease and as an adverse effect of medication such as lithium and anticonvulsants or from loss of vision, e.g., cataracts, vitreous hemorrhage, and optic atrophy [11][12][13][14][15][16]44]. Although the mechanism of periodic alternating nystagmus is not clearly understood, lesions of the uvula and nodules as well as structures located in the posterior vermis of the cerebellum, have been shown to be temporally related to its occurrence [45].…”

“…Infantile (a)periodic alternating nystagmus (IAPAN) has all the electrophysiological and clinical characteristics of INS except like acquired PAN the null zone shifts position in a regular (periodic) or irregular (aperiodic) pattern [11][12][13][14][15][16]44]. This results in changes in the intensity and/or direction of the nystagmus and dynamic changes in visual function and anomalous head positioning from seconds to minutes.…”

“…The major clinical characteristics of INS with variable association include: increased intensity with fixation, decreased intensity with sleep, variable intensity due to eye position in orbit or gaze (eccentric null position), changing direction in different positions of gaze (neutral positions), decreased intensity with convergence (damping), changing direction and/or intensity with monocular occlusion ("latent component"), anomalous head posturing, strabismus and dissociated horizontal and vertical deviations [8][9][10]. In addition to the above characteristics, up to 33% of patients with OCA1 and INS will have an inherent, rhythmic, periodic or (a)periodically changing nystagmus intensity and/or direction over time [11][12][13][14]. Most clinicians are familiar with this oscillation as acquired periodic alternating nystagmus (PAN).…”