1. BRCA1 Around the World

Since the BRCA (BReast CAncer) gene was identified in the early 1990’s, studies from around the world have documented 1,650 BRCA1 and 1,731 BRCA2 unique mutations. In 2018, a group of researchers called the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) published a paper that analyzed these mutations by mutation type (pathogenicity),  family count, and race/ethnicity to characterize the worldwide distribution of BRCA mutations in the CIMBA dataset. Because the tabular data had over 3000 entries, I wanted to create a visual means to explore the distribution of each mutation, allowing the viewer to select a country or mutation to explore the associated references.

Using the data supplied in the paper supplement (NIHMS938537-supplement-Supp_TableS1), I separated the data for BRCA1 from BRCA2, and added a data column for the position of each mutation on the gene according to its cDNA sequence number (ie: c.34C>T begins at nucleotide 34). All other data columns were included in the visualization, excluding the columns for “Mutation function” and “Mutation class”. To make the data more accessible, I summarized the data contained in each chart in plain language. 

To allow the viewer to interact with the data, I constructed the visualization in Tableau. The first graph shows a simple geographic map of the BRCA1 distribution that allows the viewer to see the number of families and mutations in each country. In the second visualization, the viewer can see the number of families with a specific BRCA1 mutation (bubble size) and the corresponding “pathogenicity” of the mutation (color). I used a stacked bar graph in the third visualization to illustrate the racial distribution of all mutations by country. Finally, to show the overall frequency of each mutation, I created a treemap graph of all mutations that occurred in at least two countries arranged by size (# countries) and color (# families).  The viewer can filter all graph data by mutation, ethnicity, or country.