Phenotype Track

These maps synthesize and present existing data linking a specific phenotype to a region of chromosome 18. The data here are from various datasets, including linkage studies and GWAS data as well as studies presenting molecularly defined critical regions for specific gene dosage phenotypes. The Phenotype Track regions are color coded using the same scheme as used for the Gene Dosage Map although not all categories apply. Also, the hemizygous and suprazygous classifications are combined here primarily because there are so little data regarding the effects of suprazygosity.

Once the specific gene is identified for a phenotype, the data will be removed from this map. If the molecular mechanism of the disease is either haploinsufficiency or suprasufficiency, the information will be linked to the appropriate gene on the “Gene Dosage” tracks. The Phenotype track will be regularly curated as new data become available. As chromosome 18 is relatively gene-poor, we expect to be able to regularly update the map with the latest information. This is in contrast to the OMIM phenotype data on the UCSC Genome Browser, which will identify a region and a phenotype based on the first report and then only update their map when the causative gene is identified. Thus, we hope to provide a unique resource for the research community.

Hemizygosity phenotype classes

1. Mechanism of disease not related to gene dosage (genes indicated in blue)
   • Recessive inheritance
   • Dominant negative disease mechanism
2. Low penetrance disease occurring in fewer than 50% of people with hemizygosity. (genes indicated in orange)
3. Causal of disease if hemizygous with a penetrance of at least 50% (genes indicated in pink)
   • Based on our study data
   • Based on data from the heterozygous knockout mouse
   • Based on human disease literature
4. Haplolethal (genes indicated in red)
   • In a critical region never found in hemizygosity in people
5. Unknown – no data are available regarding this phenotype and hemizygosity or heterozygous loss of function. (genes indicated in gray)

Suprazygosity phenotype classes

1. Mechanism of disease not related to gene dosage (genes indicated in blue)
   • Recessive inheritance
   • Dominant negative disease mechanism
2. Low penetrance disease occurring in fewer than 50% of people with suprazygosity. (genes indicated in orange)
3. Causal of disease if suprazygous with a penetrance of at least 50% (genes indicated in pink)
   • Based on our study data
   • Based on data from animal models
   • Based on human disease literature
4. Unknown – no data are available regarding this phenotype and suprazygosity (genes indicated in gray)