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Chromosome 19q cone-rod retinal dystrophy. Ocular phenotype
K Evans1, J Duvall-Young, F W Fitzke
1Department of Clinical Ophthalmology, Institute of Ophthalmology, London.
Archives of Ophthalmology (Chicago, Ill. : 1960)
|February 1, 1995
Summary
This study details a family with dominant cone-rod dystrophy, revealing early vision loss and a unique phenotype. Further research is needed to link genetic mutations to clinical presentations in this retinal dystrophy.
Area of Science:
- Ophthalmology
- Genetics
- Medical Research
Background:
- Cone-rod dystrophy (CRD) is a group of inherited retinal diseases.
- Autosomal dominant CRD linked to chromosome 19q presents a challenge in classification.
Purpose of the Study:
- To characterize the clinical phenotype of a family with dominantly inherited CRD.
- To correlate the observed phenotype with existing CRD classifications.
- To investigate the genetic basis of CRD in this family.
Main Methods:
- Clinical examination and Goldmann perimetry were performed on 34 affected and 22 unaffected family members across four generations.
- Detailed psychophysical and electrophysiologic testing (electroretinography, perimetry, dark adaptometry) were conducted on younger affected individuals.
- Genetic linkage analysis identified a locus on chromosome 19q.
Main Results:
- Visual acuity loss began in the first decade, with night blindness after age 20, and severe vision loss by age 50.
- Fundus changes progressed from central to peripheral, accompanied by central scotomas and visual field defects.
- Early testing (before age 26) indicated a greater loss of cone function than rod function.
Conclusions:
- The described CRD phenotype does not align with established subtypes.
- Further investigation is required to establish genotype-phenotype correlations for CRD.
- Understanding genetic mutations is crucial for classifying and potentially treating CRD.