Butterfly-Shaped Pattern Dystrophy: Clinical Features, Genetics, and Findings

Case Study

A 46-year-old woman presented for routine ophthalmic evaluation with mild complaints of intermittent blurred central vision in both eyes.

Get the All-fit Adapter

She reported no history of night blindness or significant visual loss. Her medical history was unremarkable. Best-corrected visual acuity was 20/25 in both eyes.

Anterior segment examination was normal. Fundus examination revealed bilateral, symmetric pigmentary changes in the macular region with a distinctive butterfly-shaped pattern radiating from the fovea.

The lesions consisted of irregular, yellow-brown pigment deposition at the level of the retinal pigment epithelium (RPE).

Optical coherence tomography (OCT) demonstrated subtle irregularities and hyperreflective deposits at the RPE level without significant disruption of the outer retinal layers.

Fundus autofluorescence (FAF) showed a characteristic pattern of mixed hyperautofluorescent and hypoautofluorescent areas corresponding to the pigmentary changes.

Full-field electroretinography (ERG) was normal. Based on the clinical findings and characteristic macular appearance, a diagnosis of butterfly-shaped pattern dystrophy was established.

Disease Entity

Butterfly-shaped pattern dystrophy is a form of pattern dystrophy of the retinal pigment epithelium characterized by pigmentary deposits in the macula arranged in a butterfly-like configuration.

It belongs to a group of inherited macular disorders collectively referred to as pattern dystrophies.

Pattern dystrophies are typically associated with mutations in the peripherin/RDS (PRPH2) gene, which encodes a photoreceptor membrane glycoprotein essential for maintaining the structural integrity of photoreceptor outer segments.

Butterfly-shaped pattern dystrophy is characterized by the accumulation of lipofuscin-like material within the RPE, producing distinctive pigmentary patterns visible on fundus examination.

The disease usually manifests in mid-adulthood and generally follows a relatively benign course compared with other macular dystrophies.

Pathophysiology

The pathogenesis of butterfly-shaped pattern dystrophy involves dysfunction of the retinal pigment epithelium and abnormal metabolism of photoreceptor outer segments.

Mutations in the PRPH2 gene disrupt the normal structure and function of photoreceptor outer segment discs.

This leads to impaired processing of photoreceptor debris by the RPE and subsequent accumulation of lipofuscin and other metabolic byproducts.

Lipofuscin accumulation within RPE cells alters their normal metabolic function and produces characteristic pigmentary changes visible clinically.

The distribution of these deposits in a butterfly-shaped pattern forms radiating patterns resembling butterfly wings centered on the macula.

Despite these structural abnormalities, photoreceptor function often remains relatively preserved for many years, which explains the mild symptoms and slow disease progression.

Over time, however, progressive RPE dysfunction may lead to complications such as geographic atrophy or choroidal neovascularization.

Epidemiology

Butterfly-shaped pattern dystrophy is a rare inherited retinal disease. It most commonly presents in individuals between the third and fifth decades of life.

The disorder typically follows an autosomal dominant inheritance pattern, although sporadic cases may occur.

Both sexes are affected equally, and there is no known racial predilection.

Because symptoms are often mild, the condition may remain undiagnosed until middle age when routine ophthalmic examinations reveal characteristic fundus changes.

Clinical Features

Many patients with butterfly-shaped pattern dystrophy are asymptomatic at early stages.

When symptoms occur, they may include:

Mild central visual blur
Metamorphopsia
Slight reduction in visual acuity
Difficulty reading in dim illumination

Visual acuity is often preserved in early stages, frequently remaining better than 20/40.

The hallmark clinical feature is a bilateral, symmetric pigmentary pattern in the macula resembling butterfly wings.

These pigment deposits appear as:

Yellow-brown or grayish lesions
Radiating from the foveal center
Located at the level of the RPE

The lesions may become more prominent over time.

Examination Findings

Anterior segment examination is usually normal.

Fundus examination reveals:

Characteristic butterfly-shaped pigment deposition
Macular involvement centered around the fovea
Symmetric bilateral lesions
Minimal surrounding retinal changes in early stages

Optical Coherence Tomography (OCT)

OCT findings may include:

Hyperreflective deposits at the level of the RPE
Mild irregularity of the RPE band
Preserved ellipsoid zone in early disease

Fundus Autofluorescence (FAF)

FAF typically demonstrates:

Areas of hyperautofluorescence corresponding to lipofuscin accumulation
Patchy hypoautofluorescence in regions of RPE degeneration

Fluorescein Angiography (FA)

FA may show:

Window defects due to RPE changes
Minimal leakage in most cases

Electrophysiologic Testing

Full-field ERG is usually normal. Multifocal ERG may show localized macular dysfunction in advanced stages.

Differential Diagnosis

Butterfly-shaped pattern dystrophy should be distinguished from other macular disorders with pigmentary changes.

Important differential diagnoses include:

Adult-onset foveomacular vitelliform dystrophy
Stargardt disease
Age-related macular degeneration (AMD)
Best vitelliform macular dystrophy
Other pattern dystrophies of the RPE

Stargardt disease typically presents earlier in life and is associated with widespread flecks and progressive visual loss.

Age-related macular degeneration generally occurs later in life and is associated with drusen and geographic atrophy.

Best disease shows characteristic vitelliform lesions and abnormal electro-oculography.

Careful clinical evaluation and imaging help distinguish these conditions.

Diagnosis

Diagnosis is based on characteristic clinical findings and supportive imaging studies.

Diagnostic features include:

Butterfly-shaped pigment pattern in the macula
Bilateral symmetric lesions
Onset in mid-adulthood
Normal or near-normal ERG

Genetic testing may confirm PRPH2 mutations, although it is not always required.

Multimodal imaging, including OCT and FAF, plays an important role in confirming the diagnosis and monitoring disease progression.

Management

There is currently no specific treatment for butterfly-shaped pattern dystrophy.

Management focuses on monitoring for potential complications, particularly:

Choroidal neovascularization
Progressive macular atrophy

Recommended management strategies include:

Regular ophthalmic examinations
Periodic OCT imaging
Patient education regarding symptoms of neovascular complications

If choroidal neovascularization develops, treatment with intravitreal anti–vascular endothelial growth factor (anti-VEGF) agents may be indicated.

Low-vision aids may be useful in advanced cases with significant central vision impairment.

Prognosis

The prognosis for butterfly-shaped pattern dystrophy is generally favorable.

Most patients maintain relatively good visual acuity for many years, and disease progression is usually slow.

However, some individuals may develop complications such as:

Choroidal neovascularization
Geographic atrophy of the RPE
Progressive central vision loss

Regular monitoring is therefore recommended.

Would you have interest in taking retinal images with your smartphone?

Fundus photography is superior to fundus analysis as it enables intraocular pathologies to be photo-captured and encrypted information to be shared with colleagues and patients.

Recent technologies allow smartphone-based attachments and integrated lens adaptors to transform the smartphone into a portable fundus camera and Retinal imaging by smartphone.

RETINAL IMAGING BY YOUR SMARTPHONE

References

American Academy of Ophthalmology. Basic and Clinical Science Course (BCSC): Retina and Vitreous. San Francisco, CA: AAO; latest edition.
Yanoff M, Duker JS. Ophthalmology. 5th ed. Elsevier; 2019.
Traboulsi EI. Genetic Diseases of the Eye. 2nd ed. Oxford University Press, 2012.
Marmor MF, Byers B. Pattern dystrophy of the retinal pigment epithelium. Arch Ophthalmol. 1977;95(4):646–652.
Boon CJ, van Schooneveld MJ, den Hollander AI, et al. The spectrum of retinal dystrophies caused by mutations in the peripherin/RDS gene. Prog Retin Eye Res. 2008;27(2):213–235.
Querques G, Massamba N, Srour M, et al. Pattern dystrophies of the retinal pigment epithelium: a review. Surv Ophthalmol. 2011;56(1):1–27.