Ocular Albinism – May, 2024
History:
A 30-year-old male presented for retinal exam after general ophthalmologist could not refract him to 20/20. He reported poor vision since childhood. He had also been to an optometrist recently and reportedly was told his right eye was “lazy”. He denied history of patching as a child or surgery. There was no significant family history of poor vision. His glasses prescription was minimal with a spherical equivalent of -0.50 in both eyes (OU).
Exam:
Visual acuity was 20/60 OD and 20/30 OS with best correction. Intraocular pressures were normal at 22 and 18. Anterior exam was normal with no corneal or lenticular changes. Dilated exam showed an absent foveal reflex OU. No other retinal pathology was appreciated. It was noticed during the exam that the patient has a very fair complexation, light blue eyes, and light blonde hair. Therefore, it was decided to proceed with genetic testing for oculocutaneous albinism (OCA).
OCT macula showed lack of foveal pit. No intraretinal or subretinal fluid.
Differential Diagnosis:
When considering ocular albinism, there are multiple systemic syndromes that are distinct from OCA. OCA is defined by a defect in melanin production.
The syndromic forms of albinism include:
• Hermansky-Pudlack Syndrome
• Albinoidism
• Waardenburg Syndrome
• Chediak-Higashi Syndrome
Discussion:
Ocular Albinism
Our patient’s genetic testing returned with two mutations within the TYR gene, one was identified as pathogenic, and one was a risk factor. Oculocutaneous albinism is a group of autosomal recessive conditions within melanin production. There are seven OCA types, not including the syndromic conditions above. Ocular albinism, without cutaneous findings, is a X-linked recessive condition and thus only found in males. OCA Type 1 are tyrosinase related conditions and are related to the TYR gene. There are currently over 200 genes identified to date. Tyrosinase-negative OCA lacks all pigmentation. These patients require lifetime regular ocular and dermatologic follow up.
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References:
- Seward SL Jr, Gahl WA. Hermansky-Pudlak syndrome: health care throughout life. Pediatrics. 2013 Jul;132(1):153-60.
Nayak CS, Isaacson G. Worldwide distribution of Waardenburg syndrome. Ann Otol Rhinol Laryngol. 2003;112(9 Pt 1):817. - Kaplan J, De Domenico I, Ward DM. Chediak-Higashi syndrome. Curr Opin Hematol. 2008 Jan;15(1):22-9.