1/13. Visual evoked potential evidence of albino-like chiasmal misrouting in a patient with angelman syndrome with no ocular features of albinism.An 8-month-old boy with global developmental delay, including visual and hearing inattention, was examined in the ophthalmic clinic. Monocular flash visual evoked potentials demonstrated a crossed asymmetry in scalp distribution, a feature considered to be pathognomic of albinism. Remarkably a foveal reflex was noted in each eye and this patient did not have nystagmus, iris transillumination, nor conspicuously pale fundi. The optic discs appeared normal. He was noted to have very fair skin and hair, with a small head and flat occiput. Cytogenetic studies demonstrated a microdeletion of the maternal chromosome 15q11-q13, and he was diagnosed with angelman syndrome.- - - - - - - - - - ranking = 1keywords = nystagmus (Clic here for more details about this article) |
2/13. Oculocutaneous albinism: variable expressivity of nystagmus in a sibship.Traditionally, the diagnosis of ocular or oculocutaneous albinism (OCA) is based on a constellation of features including the presence of nystagmus associated with iris transillumination defects, hypopigmentation of the fundus, and hypoplasia of the fovea and optic nerve head. Nystagmus is the most frequent ocular sign for the ascertainment of albinism particularly in individuals who have lightly-pigmented parents. We report two siblings, a male and female, with minimal, if any, pigmentation of skin and hair, iris transillumination defects, blond fundi, and hypoplasia of the foveae and optic nerve heads who were discordant for nystagmus; the diagnosis of OCA was based on the clinical findings. These siblings presumably have the same genetic hypopigmentation defect and demonstrate that nystagmus is not a consistent finding in OCA and may not be an absolute criterion for diagnosis.- - - - - - - - - - ranking = 7keywords = nystagmus (Clic here for more details about this article) |
3/13. Periodic alternating nystagmus associated with albinism.We examined a 73-year-old woman with the rare association of albinism and (presumably) congenital periodic alternating nystagmus. The mechanism of the nystagmus in this case is uncertain. Anomalous retinogeniculate pathways have been documented in albino animals. Periodic alternating nystagmus might occur in some patients with albinism if there are also anomalies in the pathways conveying visual information to the cerebellum and brainstem.- - - - - - - - - - ranking = 7keywords = nystagmus (Clic here for more details about this article) |
4/13. Visual improvement in an albinotic patient with an alteration of congenital nystagmus.Biofeedback techniques were used to alter congenital nystagmus (CN) in an albino. In response to auditory cues, the patient was able to reduce the amplitude of the nystagmus by 50% or more. In response to a combination of auditory and visual cues, the patient was able to alter the waveform of the nystagmus in such a manner that progressively larger portions of each cycle of the nystagmus were spent with the eye relatively stationary. Presumably as a consequence of this alteration in waveform, the patient's visual acuity (VA) improved from 6/35 to 6/25. The results indicate that, although VA in albinos is limited ultimately by the presence of foveal hypoplasia, other components of the typical albinotic syndrome (such as the accompanying nystagmus) can add to the acuity reduction and should, therefore, be treated.- - - - - - - - - - ranking = 9keywords = nystagmus (Clic here for more details about this article) |
5/13. Brown oculocutaneous albinism. Clinical, ophthalmological, and biochemical characterization.The clinical, ophthalmological, and biochemical characteristics of a 28-year-old black woman with brown oculocutaneous albinism were determined. hair color was medium brown and skin color was light brown, and a faint tan developed with sun exposure. The irides were light brown in the central one-third, blue-gray in the peripheral two-thirds, and showed punctate and radial translucency. visual acuity was 20/60 in the right eye and 20/100 in the left eye. There was a moderate pendular nystagmus, and previous surgeries had corrected an exotropia. The foveal reflex was muted, and the retinal pigment was reduced. Hairbulb tyrosinase activity was 1.75 pmoles/120 min/hairbulb, hairbulb glutathione content 0.83 nmoles/hairbulb, and urine excretion of 5-S-cysteinyldopa 174.9 ng/mg creatinine. Electron microscopy of hairbulb and skin melanocytes showed arrested melanosomal development. These findings suggest that there is a partial block in the distal eumelanin pathway in this form of albinism. The ophthalmological characteristics of six additional cases of this form of albinism are also presented.- - - - - - - - - - ranking = 1keywords = nystagmus (Clic here for more details about this article) |
6/13. Aland eye disease: no albino misrouting.Electrophysiological studies showed that a patient with Aland eye disease had no misrouting of the optic pathways which is always found in all forms of albinism as a consequence of the retino-geniculate anomaly. Also the spontaneous and optokinetic nystagmus did not resemble that of the large majority of human albinos. The marked asymmetry found in this patient seems to be typical for humans with a defective development of foveal binocular vision. These findings are in agreement with clinical, nystagmographic and EM findings that Aland eye disease is distinct from the Nettleship-Falls type of X-linked ocular albinism. Furthermore, Aland eye disease is different from X-chromosomal congenital stationary night blindness with myopia by the fact that the scotopic functions are only moderately affected and there is no restriction of the peripheral photopic visual fields. In addition, there is latent nystagmus of extraocular type that appears also in female carriers. There is no ophthalmoplegia, there is a progression of the myopia and the dyschromatopsia is of secondary type.- - - - - - - - - - ranking = 2keywords = nystagmus (Clic here for more details about this article) |
7/13. Oculocutaneous albinism associated with Apert's syndrome.Five of nine patients with Apert's syndrome (acrocephalosyndactyly) showed an associated hypopigmentation of hair, skin, and eyes. The hair color of these five patients ranged from light brown to blond, the skin was pale, and the irides hazel or blue. iris transillumination and hypopigmentation of the fundus were present and associated with absent or diffuse foveal reflexes. Unlike most forms of classic oculocutaneous albinism, however, there was good visual acuity and no pendular nystagmus. The evidence indicated that the lack of pigmentation associated with the characteristic skeletal anomalies of Apert's syndrome resulted from a disturbance of independent, genetically related, processes occurring at a common point in gestation.- - - - - - - - - - ranking = 1keywords = nystagmus (Clic here for more details about this article) |
8/13. Vestibulo-ocular and optokinetic deficits in albinos with congenital nystagmus.Vestibular and optokinetic responses were recorded in three albino subjects with congenital nystagmus. Although an ice-water caloric stimulus did not elicit nystagmus, all patients showed a response to rotational stimuli containing high frequency components. Vestibular responses to a constant velocity rotation decremented with abnormally short time constants of 1-2 sec (normal 15-20 sec). For sinusoidal oscillation, in one subject, the cut-off frequency (where the amplitude of the response was 70% of maximum) was increased to 0.8 Hz (normal about 0.01 Hz). Full-field optokinetic stimulation generated no nystagmus response. These abnormalities may be due to defects in networks that act as mathematical integrators : either the final common neural gaze-holding network that converts velocity into position information for the ocular motor neurons or the "velocity-storage" mechanism that normally combines sensory inputs from both the labyrinths and visual system to generate appropriate (per-rotatory) nystagmus during rotation and to suppress inappropriate (post-rotatory) nystagmus after rotation.- - - - - - - - - - ranking = 9keywords = nystagmus (Clic here for more details about this article) |
9/13. Atypical sensory nystagmus and its surgical management.Two patients with oculocutaneous albinism who had presumed sensory-defect nystagmus also showed the features of congenital motor-defect nystagmus. Both patients used an abnormal head posture to block the nystagmus, and each had coexisting strabismus. Modern surgical techniques simultaneously shifted the null point of the nystagmus to the primary position and corrected the strabismus.- - - - - - - - - - ranking = 8keywords = nystagmus (Clic here for more details about this article) |
10/13. Genetic studies of ocular albinism in a large virginia kindred.Nettleship-Falls ocular albinism is an X-linked disorder characterized by variable degrees of impaired visual acuity, nystagmus, and macular hypoplasia in affected males and variable fundus pigmentation but normal acuities in females. Because of extreme variability in clinical manifestation, examination of family members may be necessary to confirm the diagnosis and is essential for genetic counseling purposes. This study reports the pedigree analysis and clinical findings in a large kindred from rural virginia with 31 males reported to be affected among the 287 individuals in the pedigree. Clinical findings were quite variable, even within sibships, and some cases had been previously misdiagnosed, even in the presence of this remarkable family history. Linkage analysis in this family did not show the expected linkage with the Xg blood group. Examination of skin biopsies clearly indicated the cutaneous abnormality of giant pigment melanosomes (GPM) in both affected males and carrier females. Our use of light microscopy for detection of characteristic GPM may be easily employed as a carrier detection test, and therefore, provide the basis for accurate genetic counseling in families with ocular albinism.- - - - - - - - - - ranking = 1keywords = nystagmus (Clic here for more details about this article) |
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