An autosomal dominant bull's-eye macular dystrophy (MCDR2) that maps to the short arm of chromosome 4.
OBJECTIVE
To describe the phenotype of an autosomal dominant macular dystrophy and identify the chromosomal locus.


METHODS
Eleven members of a five-generation, nonconsanguineous British family were examined clinically and also underwent automated perimetry, electrodiagnostic testing, fundus fluorescein angiography, and fundus autofluorescence imaging. Blood samples were taken for DNA extraction and linkage analysis was performed.


RESULTS
The phenotype is characterized by bull's-eye macular dystrophy first evident in the first or second decade of life. There is mild visual impairment, central scotomata, and electrophysiological testing indicates that most affected individuals have disease confined to the central retina but older subjects have more widespread rod and cone abnormalities, demonstrated by flash ERG. Genetic linkage analysis established linkage to chromosome 4 at p15.2-16.3 with a maximum lod score of 3.03 at a recombination fraction of 0.00 for marker D4S391. The locus for this autosomal dominant macular dystrophy lies between flanking markers D4S3023 and D4S3022, and overlaps the Stargardt 4 locus.


CONCLUSIONS
A new locus was identified for a bull's-eye macular dystrophy on the short arm of chromosome 4.
Michaelides
Michel
M
Institute of Ophthalmology, University College London, London, United Kingdom.
Johnson
Samantha
S
Poulson
Arabella
A
Bradshaw
Keith
K
Bellmann
Caren
C
Hunt
David M
DM
Moore
Anthony T
AT
D000293:Adolescent; D000328:Adult; D002648:Child; D002874:Chromosome Mapping; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D004252:DNA Mutational Analysis; D004596:Electroretinography; D005260:Female; D005451:Fluorescein Angiography; D005799:Genes, Dominant; D008040:Genetic Linkage; D005819:Genetic Markers; D006801:Humans; D008268:Macular Degeneration / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D010641:Phenotype; D016133:Polymerase Chain Reaction; D058609:Visual Field Tests
D005819:Genetic Markers