Retinopathy in Danon disease.
OBJECTIVE
To evaluate visual function in 2 boys and their maternal aunt affected with Danon disease due to a mutation in the X-linked lysosome-associated membrane protein-2 (LAMP2) gene.


METHODS
Linkage analysis using microsatellite markers from the X chromosome was done in family members from the paternal side. Visual acuity testing, fundus analysis, fluorescence angiography, and full-field electroretinography were performed in all 3 patients.


RESULTS
Eye examinations confirmed the presence of retinopathy in the 2 boys and their maternal aunt, obligate carrier for the S157X mutation in LAMP2. The expression of the disease was milder in the female carrier than in the hemizygous boys, possibly due to lyonization.


CONCLUSIONS
Our report further expands the phenotype of Danon disease by describing retinopathy in 3 cases. A thorough clinical examination, including ophthalmic investigation, is needed in all cases of Danon disease.


CONCLUSIONS
LAMP2 belongs to a growing number of retinopathy genes. Genes involved in systemic diseases associated with poor survival may see their effect in other organs, not only in the eyes, becoming a major source of concern once a good and reliable therapy is available. This also represents a major issue for genetic counseling for patients undergoing gene therapy in the future.
Schorderet
Daniel F
DF
Institut de Recherche en Ophthalmologie, Avenue de Grand-Champsec 64, 1950 Sion, Switzerland. daniel.schorderet@iro.vsnet.ch
Cottet
Sandra
S
Lobrinus
Johannes Alexander
JA
Borruat
François-Xavier
FX
Balmer
Aubin
A
Munier
Francis L
FL
D000293:Adolescent; D041321:Chromosomes, Human, X / Q000235:genetics; D004596:Electroretinography; D005260:Female; D005451:Fluorescein Angiography; D008040:Genetic Linkage; D052120:Glycogen Storage Disease Type IIb / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D052119:Lysosomal-Associated Membrane Protein 2; D051907:Lysosomal Membrane Proteins / Q000235:genetics*; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D012164:Retinal Diseases / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D035781:Siblings; D014792:Visual Acuity
C497811:LAMP2 protein, human; D052119:Lysosomal-Associated Membrane Protein 2; D051907:Lysosomal Membrane Proteins