The purpose of the study is to identify the molecular defects of CORD, to evaluate the clinical course as a function of the molecular defect, and to assess the modifying role of environmental factors.
ID
Source
Brief title
Condition
- Eye disorders congenital
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Primary study parameters
These are genetic mutations and haplotypes.
Primary outcome of the study
CORD.
Secondary outcome
Secundary study parameters
Age, sexe, tabacco intake, UV-exposition, intake of anti-oxidants and
omega-3-lipids (DHA en EPA), vascular co-morbidity
Secundary outcome
Visual acuity, age of onset, quantification of color vision defects, photopic
ERG responses, bull's eye maculopathy
Background summary
Cone (rod) dystrophy: identification of the molecular defects and clinical
consequences
Cone (rod) dystrophy(CORD) is a juvenile hereditary macular disorder
characterized by loss of cone photoreceptor cells. The estimated prevalence is
1/10.000. The first symptoms of CORD are decreased visual acuity and color
visions defects. This generally leads to functional blindness. Currently, no
therapeutical options are available to prevent, stabilize or cure this disease.
CORD is heterogeneous and autosomal dominant, autosomal recessive and X-linked
inheritance has been described. Ten genes have been identified: RPGR
(X-linked), CNGB3, ABCA4, GUCA1A, GNAT2, CNGA3, RDH5, RIMS1, RCD1, GUCY2D, and
15 additional loci. The attributable risk of these genes to the disease
occurrence, however, is low and the cause of the majority of CORD is still
unknown.
This lack of knowledge hampers genetic counseling of patients. Patients are not
adequately informed about their visual prognosis, can not be treated, and do
not know how to improve their lifestyle to alter the course of the disease.
Study objective
The purpose of the study is to identify the molecular defects of CORD, to
evaluate the clinical course as a function of the molecular defect, and to
assess the modifying role of environmental factors.
Study design
1. 150 CORD probands will be recruited from eye clinics and low vision
institutes. The entire clinical chart of each patient will be studied for age
of onset, all clinical parameters to diagnose CORD, and visual acuity per 5
years.
2. 200 unrelated controls will be recruited from the same clinics.
3. Analysis of all known genetic mutations with standard procedures.
4. Analysis of unknown mutations with linkage analysis, genome wide SNP arrays,
and specific retinal gene arrays.
5. Risk analysis of disease mutations and haplotypes, genotype-fenotype
associations, and analysis of gene-environment interactions.
Study burden and risks
The assessment of clinical parameters to diagnose CORD are part of the regular
ophthalmologic exam performed by ophthalmologists. Parameters are collected
retrospectively by medical charts. If parameters are incomplete, patients will
be invited for further diagnostic work-up.
The questionnaire is additional for the patient and will take a maximum of an
hour.
Dr. Molewaterplein 40
3015 GD Rotterdam
NL
Dr. Molewaterplein 40
3015 GD Rotterdam
NL
Listed location countries
Age
Inclusion criteria
<50 years
decreased visual acuity in all three axes
color vision defects
decreased or absent photopic ERG
central scotoma on visual field
Exclusion criteria
> 50 years
normal visual acuity
normal color vision
normal ERG responses
no central scotoma
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL18730.078.07 |