Visual electrophysiology can play an important role in the detection of visual pathway misrouting, helping to determine the diagnosis, particularly if the phenotype is mild or “sub-clinical”. 2 Ocular signs such as foveal hypoplasia and nystagmus are common in both OCA and OA but there is wide phenotypic variation and overlap. Ocular albinism is distinguished by predominant involvement of the ocular tissues and X-linked inheritance, with the ocular hypopigmentation occurring to a lesser degree than in OCA. 1 OCA can also occur in several syndromic disorders with systemic complications posing significant morbidity, highlighting the importance of early diagnosis. The hallmark clinical features of OCA include congenital hypopigmentation of the skin, hair and eyes, with an autosomal recessive inheritance mode. In the eye cup, this results in a cascade of ocular abnormalities and intracranial visual pathway misrouting, common to both oculocutaneous albinism (OCA) and ocular albinism (OA). Differential diagnosis is considered in the context of suspected retinal and other disorders, including rare syndromes that may masquerade as albinism.Īlbinism describes a heterogeneous group of genetically determined disorders characterized by disrupted synthesis of melanin pigmentation or melanosome maturation during development. The role of visual electrophysiology in the detection of chiasmal dysfunction and visual pathway misrouting is emphasized, highlighting how age-associated changes in visual evoked potential (VEP) test results must be considered to enable accurate diagnosis, and illustrated further by the inclusion of novel VEP data in genetically confirmed cases. This study reviews the prevalence, genetics and ocular manifestations of OCA and OA, including abnormal development of the optic chiasm. The main ocular features common to both oculocutaneous albinism (OCA), and ocular albinism (OA) include reduced visual acuity, refractive errors, foveal hypoplasia, congenital nystagmus, iris and fundus hypopigmentation and visual pathway misrouting, but clinical signs vary and there is phenotypic overlap with other pathologies. Albinism describes a heterogeneous group of genetically determined disorders characterized by disrupted synthesis of melanin and a range of developmental ocular abnormalities.
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