Susannah went by her middle name Catherine, and more commonly Catie or Katie (as is on her husband's tombstone). She is interred at Liberty Hill Primitive Baptist Church Cemetery, Liberty Hill, Lamar County, Georgia
At one point, William Pringle and Mary McCoy were listed as Catherine's parents, but without any supporting documentation (the origin of this was a GedCom upload). FamilySearch.com and other modern genealogy sources list a different set of parents, John Pringle and Rebecca Simpson, also without any supporting documentation.
However, the location of the families tends to support William and Mary as being correct, as they appear to have both spent their entire lives in South Carolina, where Catie was born. John and Rebecca appear to have both spent their entire lives in the Shelby, Kentucky region, and all of their other children listed on FamilySearch were born in Kentucky. Even though this circumstantial evidence favors William and Mary, I have left Catherine's profile unconnected for now, until more reliable sources can be found.
"United States Census, 1850," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MZYH-41K : 12 April 2016), Catherine Gardner in household of John Gardner, Monroe county, Monroe, Georgia, United States; citing family 940, NARA microfilm publication M432 (Washington, D.C.: National Archives and Records Administration, n.d.).
It may be possible to confirm family relationships with Catherine by comparing test results with other carriers of her mitochondrial DNA.
However, there are no known mtDNA test-takers in her direct maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Catherine: