Spectral Domain OCT Findings in Malattia Leventinese Yu

Spectral Domain Optical Coherence Tomography Findings in Malattia Leventinese
Yu Cheol Kim
Department of Ophthalmology, Keimyung University School of Medicine, Dong-san Medical Center, Dae-gu, South Korea
INTRODUCTION
Malattia leventinese (ML), also known as Doyne’s honeycomb retinal dystrophy
(DHRD) or dominant radial drusen (Mendelian Inheritance in Man [MIM] no. 126600),
is a rare autosomal dominant retinal dystrophy characterized by the appearance in
early adult life of small radial macular and parapapillary drusen with later confluent soft
drusen in the macular area. A single missense mutation (arg345trp) in the EFEMP1
(EGF-containing fibrillin-like extracellular matrix protein) gene was identified in families
with ML. Retinal atrophy and choroidal neovascularization with subsequent visual loss
can occur during the fourth and fifth decades of life.
We have characterized clinically and genetically six members of a three-generation
family affected by ML. They were prospectively analyzed by optical coherence
tomography (OCT/SLO; OTI, Toronto, Ontario, Canada).
METHOD & MATERIAL
Six family members in three generations were examined. Four patients diagnosed with
ML were included in this study. The diagnosis was confirmed with the presence of
R345W mutation and fundus findings consistent with ML. Best –corrected visual acuity,
slit lamp examination, fundus color photography and OCT were performed.
P2-2 patient without R345W mutation shows normal fundus and OCT findings.
Although P3-1 patient has the mutation, she shows no evidence of ML/DHRD.
Because she is too young to show gene expression, which starts usually at the age
of 30 to 40 years.
DISCUSSION
1. Layer thickness
RESULTS
Hyper-reflective drusen were identified between retinal pigment epitheliums (RPEs)
and Bruch membranes (BMs) with nodular or dome-shaped elevations, which
coalesce to form a solid plaque layer. RPE and BM were assumed to be dissociated,
changing the hyper-reflective space where drusen should be located into hyporeflective fluid. RPE hyperplasia and pigmentary change were followed. Confluent
drusen were presumed to obscure and destroy the adjacent outer retina. The choroid
layer was getting thinner, followed by retinal thinning. Choroidal neovascularization
(CNV) was not identified.
Confluent drusen can disrupt the outer retina layer
(outer segment layer, inner segment layer, outer
nuclear layer), although the thickness from Bruch’s
membrane to internal limiting membrane is not
affected initially. Choroidal atrophy (thinning) is
followed by sensory retinal thinning.
☞outer retinal disruption by drusen→choroidal atrophy→sensory retinal thinning
2. RPE changes
Small and discrete drusen become confluent and form
the honeycomb appearance. The RPE and the BM seem
to be dissociated ,with an accumulation of a hyporeflective fluid between the two layers (1st fig.: red arrow
& 2nd fig.: double high reflectivity). RPE hyperplasia and
pigmentary changes (3rd fig.: high reflectivity) show
posterior shadowing (4th fig.: blue arrow). The weak
posterior shadowing induced by early RPE hyperplasia is
often confused as the RPE/BM dissociation.
☞ granular drusen → confluent fluid drusen
→ RPE/BM dissociation
RPE hyperplasia & pigmentary changes
3. Choroidal atrophy and ischemic optic atrophy
Proband’s right eye shows flame-shaped retinal hemorrhage and macular edema due
to central retinal vein occlusion.
Confluent drusen may destroy the photoreceptor layer.
Subsequent choroidal atrophy can expand to peripapillary area,
inducing ischemic optic atrophy. Choroidal atrophy is assumed
to be the main cause of visual loss in ML/DHRD, rather than
CNV.
☞ granular macular drusen → confluent drusen in macular and parapapillary region
→ macular and parapapillary choroidal atrophy → optic nerve atrophy
CONCLUSION
This is the first report of describing a Korean family with variable expressivity of
ML/DHRD. SD-OCT and fluorescein angiography may be helpful in determining the
long term outcome of macular and visual function.
REFERENCES
1. Souied EH, Leveziel N, et al. Optical coherent tomography features of malattia
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2. Toto L, Parodi MB, et al. Genetic heterogeneity in malattia leventinese. Clin Genet
2002;62:339-403.
3. Gerth C, Zawadzki RJ, et al. Retinal microstructure in patients with EFEMP1
retinal dystrophy evaluated by fourier domain OCT. Eye 2008;23:480-83