Autosomal dominant cone-rod retinal dystrophy (CORD6) from heterozygous mutation of GUCY2D, which encodes retinal guanylate cyclase.
OBJECTIVE
To describe the clinical features of autosomal dominant cone-rod retinal dystrophy (CRD) in a British family mapping to chromosome 17p12-p13 (CORD6), with a heterozygous mutation (Glu837Asp/ Arg838Ser) of GUCY2D.


METHODS
A prospective, clinical family survey.


METHODS
Ten affected members of a family with autosomal dominant CRD.


METHODS
Full clinical examinations were undertaken. Selected affected family members underwent electrophysiologic evaluation, scotopic static perimetry, dark adaptometry, and color vision assessment.


METHODS
Clinical appearance and electroretinographic responses.


RESULTS
Typical clinical and electroretinographic features of childhood-onset CRD were recorded. In addition, moderate myopia and pendular nystagmus were seen in affected individuals. Color vision assessment in the youngest affected individual showed no color discrimination on a tritan axis, but retention of significant red-green discrimination. Electronegative electroretinogram responses were seen on electrophysiology in the only young family member examined.


CONCLUSIONS
The phenotype associated with GUCY2D CRD is clinically distinct from that associated with other dominant CRD loci. Unusual electroretinographic responses may indicate that this mutation of GUCY2D is associated with early defects in photoreceptor synaptic transmission to second-order neurons.
Gregory-Evans
K
K
Department of Clinical Ophthalmology, Moorfields Eye Hospital, London, England.
Kelsell
R E
RE
Gregory-Evans
C Y
CY
Downes
S M
SM
Fitzke
F W
FW
Holder
G E
GE
Simunovic
M
M
Mollon
J D
JD
Taylor
R
R
Hunt
D M
DM
Bird
A C
AC
Moore
A T
AT
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002874:Chromosome Mapping; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics*; D003117:Color Vision Defects / Q000175:diagnosis; D004596:Electroretinography; D005260:Female; D005799:Genes, Dominant / Q000235:genetics*; D008040:Genetic Linkage; D006162:Guanylate Cyclase / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000175:diagnosis; D009759:Nystagmus, Pathologic / Q000175:diagnosis; D010375:Pedigree; D020419:Photoreceptor Cells, Vertebrate / Q000201:enzymology* / Q000473:pathology; D017354:Point Mutation; D011446:Prospective Studies; D012162:Retinal Degeneration / Q000175:diagnosis / Q000201:enzymology / Q000235:genetics*; D014785:Vision, Ocular / Q000235:genetics; D014792:Visual Acuity
D006162:Guanylate Cyclase