GeneDx :: Tests :: Stargardt Disease, Fundus Flavimaculatus, Macular Dystrophies, Stargardt-Like Macular Dystrophy, and Cone-Rod Dystrophy

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Stargardt Disease, Fundus Flavimaculatus, Macular Dystrophies, Stargardt-Like Macular Dystrophy, and Cone-Rod Dystrophy

ABCA4 (ATP-binding cassette, sub-family A (ABC1), member 4)
ELOVL4 (elongation of very long chain fatty acids-like 4)
PRPH2/RDS (peripherin 2)

Stargardt disease (STGD) / Fundus Flavimaculatus (FFM) ) is the most common autosomal recessive macular dystrophy with an estimated prevalence of 1 in 10,000 individuals. STGD manifests in the first or second decade of life with decreased central vision, and the appearance of orange-yellow flecks distributed in the posterior pole, sometimes extending beyond the vascular arcade. A milder form of the same disorder, fundus flavimaculatus, has a later age at onset, slower progression, and more-widespread distribution of the flecks.

Macular Dystrophies The pattern dystrophies constitute a group of disorders characterized by deposits of yellow orange or grey pigment, predominantly in the macular area that can resemble the flecks seen in Stargardt disease. Five main categories of pattern dystrophies are discriminated on the basis of the pattern of pigment distribution: adult-onset foveomacular vitelliform dystrophy, butterfly-shaped pigment dystrophy, reticular dystrophy of the pigment epithelium, multifocal pattern dystrophy simulating fundus flavimaculatus.

Stargardt-like macular dystrophy, autosomal dominant is clinically very similar to Stargardt disease. It is a highly penetrant retinal disorder, with typical onset in childhood characterized by progressive loss of central vision followed by a rapid progression to legal blindness. This disorder is characterized by an atrophic macular lesions with sharp borders associated with or without yellow fundus flecks. The lesion becomes more advanced over the course of a few years with increased atrophy of the retinal pigment epithelium that resembles the lesions seen in patients with autosomal recessive Stargardt disease. Age of onset does vary greatly within and between families.

Using genomic DNA obtained from a venous blood sample (2-5 mL in EDTA), all coding exons of the ABCA4, ELOVL4 and RDS (PRPH2) genes and their splice junctions are sequenced using a novel solid-state sequencing-by-synthesis process that allows sequencing a large number of amplicons in parallel. For analysis, DNA sequence is assembled and compared to the published genomic reference sequences. The presence of any potentially disease-associated sequence variant(s) is confirmed by conventional dideoxy DNA sequence analysis. Targeted array CGH analysis with exon-level resolution (ExonArrayDx) is available to evaluate for a deletion or duplication of one or more exons of the ABCA4, ELOVL4, and RDS (PRPH2) genes. Mutations found in the first person of a family to be tested are confirmed by repeat analysis using sequencing, restriction fragment analysis, or another appropriate method.

Information Sheet, including prices and CPT codes
Consent Document
Genetic Test Sample Submission Form (Test Requisition Form) including Payment Options

ABCA4, ABCR, Stargardt disease, cone-rod dystrophy, retinitis pigmentosa, fundus flavimaculatus, macular dystrophy, cone dystrophy, yellow flecks, nyctalopia, night blindness, retina.