- Disease categories are based on common usage, and the categories do not account for
diseases which overlap (for example, retinitis pigmentosa and cone-rod dystrophy).
That is, these categories are arbitrary to some extent.
- For Table A each disease-causing gene is counted
once only. This can be misleading, since different mutations in some genes can
cause more than one disease. In these cases, only the first-reported disease is counted.
The first-reported disease is usually the most common disease.
- For Table B all diseases caused by different
mutations in a single gene are included. Therefore a gene symbol may appear in
more than one category. Table B includes more disease categories (including
deafness) than Table A and the number of symbols per category is greater.
For example, different mutations in ABCA4 can cause recessive Stargardt disease,
recessive MD, recessive RP, recessive fundus flavimaculatus, and recessive cone-rod dystrophy,
and may contribute to AMD. As a result, ABCA4 is listed once in Table A but several times in
Table B and also in Table C.
- Dates for mapped and cloned genes, shown in the
summary graph, are based on the month and year of first publication in
a peer-reviewed journal (abstracts are not counted). In cases where a gene
was cloned and mapped before its role in retinal disease was known, the date
of the first publication reporting a disease association was used for both
"mapped" and "cloned" dates.
- Table C was added on May 15, 2005 to list symbols of genes associated with complex forms
of retinal disease. The Diseases table includes both 1) genes
and loci causing Mendelian diseases and 2) genes only associated with complex diseases.
Genes only associated with complex diseases are not included in Tables A and B
nor in the graph.
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Notes