Natalie Ainscough1,2, Christopher Barnett1,3, Deepa Taranath1,2
Purpose: Analyse the correlation between the phenotype of Albinism cases attending the Ocular Genetics Clinic and the genotypes identified in those patients following comprehensive genetic testing for known Albinism genes.
Method: This retrospective audit involved 90 families who attended between March 2013 – March 2016. Probands or family members with suspected or confirmed Albinism were identified from their clinical records and included in this audit.
Results: Twenty-one probands and 71 family members were assessed with Albinism or suspected Albinism, and their clinical records and genetic test results retrospectively reviewed for the purpose of this audit.
Six probands, plus 5 family members, were confirmed to have genetic mutations associated with Albinism. Nine had pathogenic mutations which either confirmed the clinical diagnosis or changed the diagnosis, 2 were identified as carriers and 1 had genetic changes of unknown significance. Genetic test results are currently awaited in 7 cases, as of June 2016.
Ocular and non-ocular features in gene positive patients were analysed in relation to the genetic changes confirmed by the Clinical Geneticist. Genetic analysis results and the correlation to the patient’s phenotypic appearance, particularly ocular features (nystagmus, iris transillumination, foveal hypoplasia, crossed asymmetry on VEP) in this cohort are discussed.
Conclusion: Oculocutaneous Albinism is a complex condition with complex genotypes and phenotypes. Modern day gene testing methods are now helping us understand the inheritance patterns and its heterogeneity. Clinical diagnosis in itself is not always confirmatory of the inheritance pattern in the family.