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    A 38-year-old male complains of poor vision since childhood

    Patient has light pigmentation, nystagmus, iris transillumination defects: What is the diagnosis?

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    Grand Rounds Editors
    A 38-year-old Hispanic male presented to the Bascom Palmer Eye Institute clinic complaining of poor vision since childhood. The patient stated that his vision had been poor since he was a child and wanted to know if glasses could help his vision. He denied any ocular pain, redness, discharge, flashing lights, floaters, or diplopia. His medical history and surgical history were unremarkable. His family history was significant due to having four siblings who have good vision and four half-siblings (through the patient's mother) who, to the best of the patient's knowledge, also have good vision. The patient has a maternal uncle who has a male child with poor vision. The patient was born in Honduras and denied any alcohol, tobacco, or illicit drug use.

    Examination


    Figure 1 Color montage photographs of the right and left eye.
    The healthy-appearing patient had light, straw-colored hair and lightly pigmented skin. The patient's vision was 20/200 OU with a horizontal pendular nystagmus that remained horizontal on upgaze and downgaze. The pupils were reactive without afferent pupillary defect. Slit lamp examination of the anterior segment was unremarkable except for radial iris transillumination defects in both eyes. The cornea and lens were clear. Dilated fundus exam revealed a lightly pigmented fundus without a clinically apparent fovea (Figure 1).

    Differential diagnosis

    Differential diagnoses include ocular albinism, oculocutaneous albinism, autosomal dominant foveal hypoplasia,1 isolated foveal hypoplasia,2,3 and associated conditions such as aniridia, Chediak-Higashi syndrome, and Hermansky-Pudlak syndrome. In this patient, the lightly colored hair, lightly pigmented skin, transillumination of the irides, and lightly pigmented fundus make oculocutaneous albinism the most likely diagnosis.

    Clinical course


    Figure 2 HD-OCT raster scans of the right (2a) eye and left (2b) eye. (Illustrations courtesy of Fred Y. Chien, MD)
    To confirm that there was absence of the foveal pit, a Cirrus HD-OCT (Carl Zeiss Meditec Inc., Dublin, CA) was obtained. The optical coherence tomography images show lack of a foveal depression in both eyes (Figure 2). Review of the continuous cube scan (512 128 and 200 200) also revealed a complete absence of the foveal pit. The inner segment and outer segment junction of the photoreceptor layer was noted to be intact. Since the patient had horizontal nystagmus, a multi-focal electroretinogram could not be obtained.

    We discussed with the patient that his poor vision was the result of a congenital condition and that a strong reading addition may help him with his near vision.

    Discussion

    Albinism refers to a group of genetic disorders characterized by a deficiency in the melanin system. Clinically, patients can present with hypopigmentation of the hair, skin, and eyes (oculocutaneous albinism, [OCA]) or hypopigmentation that appears limited to the eyes (ocular albinism [OA]). While the skin may clinically appear normal in patients with ocular albinism, histopathologic examination of skin biopsy specimens of affected patients and female carriers are abnormal.4 Ocular albinism can be X-linked or autosomal recessive while oculocutaneous albinism is usually autosomal recessive.

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