Stargardt Syndrome

At a glance

The most common form of inherited juvenile macular degeneration. Characterized by a reduction of central vision with a preservation of peripheral vision. Onset before the age of 20 years; macula presents yellow-white spots of irregular shapes.

Synonyms

Stargardt Disease; Stargardt Macular Degeneration; Familial Juvenile Macular Degeneration; Juvenile Hereditary Disciform Macular Degeneration; Fundus Flavimaculatus; Central Retinitis Pigmentosa.

Incidence

1/10,000. Stargardt Syndrome is the most common cause of juvenile-onset macular degeneration.

Genetic inheritance

Autosomal recessive and autosomal dominant.

Pathophysiology

Three genes have been identified. ABCA4 mutation with gene map locus 1p22.1 is the most common cause of Stargardt Syndrome. This gene encodes a rim protein in the outer segment of the photoreceptors. Malfunction results in accumulation of lipofuscin (termed “flecks” around the macular area) with retinal pigment epithelium dysfunction and photoreceptor death. Less frequent genetic causes are mutations of PROM125 on 4p15.32 (autosomal recessive) and ELOV4 on 6q14 (autosomal dominant).

Clinical aspects

In general, the age at manifestation of the disease is between 6 and 20 years with decreased central vision being the first symptom, although some patients do not suffer from any symptoms (loss of color vision, loss of peripheral vision, photophobia, paracentral scotoma, night blindness) until the age of 40 years. Fundus flavimaculatus is the descriptive term for this macular degeneration surrounded by white-yellowish flecks and spots distributed all over the fundus, although some researchers consider fundus flavimaculatus to be an allelic variant of Stargardt disease with differences in age at onset (between 17 and 60 years), severity, and clinical course (more progressive). The rapidly progressive disease occurs usually bilaterally and symmetrically and results in legal blindness in 50% of patients by the age of 50 years. No definite treatment is available; however, novel pharmacologic treatment, gene therapy, and stem cell transplantation are being developed.

Anesthetic considerations

Especially in younger patients undergoing ophthalmic examination under general anesthesia, oculocardiac reflex with profound bradycardia should be expected. No other specific anesthetic considerations are expected to arise from this disease.

Other conditions to be considered

• X-Linked Retinoschisis: Leading cause of inherited macular degeneration in boys, with an estimated prevalence of 1 in 5,000 to 25,000 and accounts for approximately 5% of all childhood-onset, inherited retinal dystrophies. Worsening vision over time, typically between the first and the second decade.

• Best Vitelliform Macular Dystrophy: Autosomal dominant early-onset maculopathy with a characteristic deposit of a yellowish (egg yolk-like) material in the macula. Three disease stages—vitelliform, pseudohypopyon, and vitelliruptive stage. Typically, slow progress with decrease in visual acuity.

References