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Case Study 38 Oculocutaneous Albinism OCA1 type 1A tyrosinase negative Alex Manguikian PhD GWMED 2009 Charles Macri MD Learning Objectives Describe the genetics and biochemistry of OCA1 Describe the typical clinical presentation of OCA1 Review the screening and diagnostic options for OCA1 in the prenatal setting Create a plan for genetic counseling of family members for patients with OCA1 Understand the importance of thorough ophthalmic management of patients with OCA1 and the negative outcomes associated with a lack of appropriate medical management in this patient population Pretest Questions 1 What is the genetic defect that leads to the development of type 1 Oculocutaneous Albinism OCA1 and absence of melanin pigment a b c d e Mutation in tyrosinase related protein gene Mutation in the tyrosinase gene and loss of enzymatic activity Mutation in the membrane associated transporter gene Mutation in phenylalanine hydroxylase Mutation in dopamine decarboxylase 2 Which of the following clinical features is always present in OCA1 and are they present at birth a Coloboma and glaucoma present at birth b Cataract and glaucoma present at birth c Cataract and glaucoma develops during adolescence d Iris transillumination and nystagmus present at birth e Iris transillumination and nystagmus develops after 1 year f Glaucoma develops at around age 10 3 What is the mode of inheritance of OCA1 a b c d Autosomal dominant Autosomal recessive X linked recessive Mitochondrial 4 What characteristic finding is found upon fundoscopic examination of the retina a b c d e Loss of foveal reflex as result of foveal hypoplasia Retinal detachment due to instability of the retinal pigment epithelium Macular hole with vitreomacular traction Central serous chorioretinopathy Epiretinal membrane and macular pseudohole Answers 1 b 2 d 3 b 4 a Case Study The following case study was adapted from a case report published by Akeo et al Archives of Ophthalmology 1996 REF 8 A couple recently sought

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