You will need the information contained in your molecular genomics laboratory report that diagnosed the chromosome 18 condition. Instructions for how to find the information you need in your report, please view this video: “How to Read a Microarray Report“
- Select either deletion or duplication.
- Select the Genomic Build Version. This should be indicated on your genomics lab report next to the coordinates of the deletion or duplication. Look for either GRCH37/hg19 or GRCH38/hg38.
- Type in the coordinates of the deletion or duplication. The region you selected will then be indicated by an orange bar to the left of chromosome picture. If you do not know the coordinates or the Genomic Build Version, you can find them on your microarray report from the clinical diagnostic lab. Instructions for interpreting that report are here: “How to Read a Microarray Report”
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- For 18p- terminal deletions, or 18p+ terminal duplications that go from the end of the chromosome to a breakpoint, the lower bound number will be 1. The upper bound number will be the breakpoint number.
- For 18q- terminal deletions or 18q+ terminal duplications that go from a breakpoint to the end of the chromosome, the upper bound number will be the breakpoint number, and the lower bound number will be 78,077,248 for hg19 or 80,373,285 for hg38.
- For 18p or 18q interstitial deletions or duplications, there should be two breakpoint numbers in the genomics laboratory diagnostic report for you to enter as lower bound and upper bound numbers.
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- Select Genes or Phenotype Regions.
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- The Genes are the known genes on chromosome 18 with data supporting an effect when deleted or duplicated.
- The Phenotype Regions are the narrowed down regions of the chromosome associated with a particular phenotype (medical or behavioral characteristic) for which the causative gene among the many in the region is not yet identified.
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If you selected Genes:
The region you selected will be indicated by a green line next to on the picture of the chromosome. The genes in the selected region which may have a clinical impact are shown in the window with 5 columns of information. The columns from left to right are:
- The gene acronym name
- The phenotype (medical condition) potentially caused by that gene.
- The probability that the gene will cause the indicated medical issue if deleted or duplicated.
- The variation in the clinical presentation of the condition
- The strength of the evidence
The genes are shown in their order on the chromosome. When you select a gene, additional data explaining the findings will expand and appear below and its position on the chromosome will be indicated by a green line on the picture of the chromosome.
If you selected Phenotype Regions:
The region you selected will be indicated by an orange bar next to the picture of the chromosome. The phenotype regions in the selected region which may have a clinical impact are shown in the window with 5 columns of information. The columns from left to right are:
- The phenotype or medical condition
- The degree of overlap of the phenotype region with the region you selected to view. This indicates if the region you selected completely encompasses the entire phenotype region or if the phenotype region extends beyond your region of interest.
- The probability that the gene will cause the indicated medical issue if deleted or duplicated.
- The variation in the clinical presentation of the condition
- The strength of the evidence
The phenotype regions are shown in their order along the chromosome. When you select a phenotype region, additional data explaining the findings will expand and appear below and its position on the chromosome will be indicated by a pink bar on the picture of the chromosome.