The uncommon occurrence of two common inherited disorders in a single patient: a mini case series

Inherited eye disorders are genetically determined conditions that are present from birth and usually manifest early, although some may develop later in life. Despite their low incidence, they are a common etiology of pediatric blindness. The occurrence of more than one such disease in a patient is very rare.

Case series of two unrelated patients with simultaneous Stargardt disease (STGD1) as well as Stickler's Syndrome (SS), both genetically confirmed.

Patient 1: 13-year-old girl was referred for unexplained bilateral decreased vision for 6 months. She had a clinical diagnosis of SS, same as her mother. Her visual acuity was 20/200 with high myopia in both eyes. Her fundus showed foveal/perifoveal atrophy, retinal pigment epithelium (RPE) changes and beaded vitreous. Goldman visual fields (GVF) revealed enlarged blind spots with central depression. A macular dystrophy was suspected. Genetic testing revealed SS, COL11A1 gene mutation; and STGD1, ABCA4 gene mutation. Patient 2: 67-year-old female with a history of hearing loss, cleft palate, strabismus and myopia, same as her daughter and granddaughters. Her visual acuity was 20/400 and 20/250 with high myopia in both eyes. Her fundus showed macular pigment clumping and RPE atrophy with no vitreous abnormality. GVF revealed a relative central scotoma with generalized constriction. Genetic testing revealed SS, COL11A2 gene mutation; and STGD1, ABCA4 gene mutation.

If a patient's signs/symptoms cannot be explained by the working/known diagnosis, additional work up should be pursued for concomitant diseases. SS and STGD1 are commonly diagnosed inherited eye disorders and can coexist in one patient on rare occasions.