diff --git a/docs/src/examples/ExampleAnalysis.md b/docs/src/examples/ExampleAnalysis.md
index edaace5..8cbd723 100644
--- a/docs/src/examples/ExampleAnalysis.md
+++ b/docs/src/examples/ExampleAnalysis.md
@@ -39,7 +39,7 @@ counts = readstereoseq(stereoseq_file)
 ````
 
 ````
-GridCounts{InlineStrings.String15, Int16} (10500, 13950) with 26177 genes
+GridCounts{String,Int16} (10500, 13950) with 26177 genes
 ````
 
 We also load pre-defined cell-type signatures
diff --git a/src/IO.jl b/src/IO.jl
index 498c3e5..d9d2a8a 100644
--- a/src/IO.jl
+++ b/src/IO.jl
@@ -42,6 +42,7 @@ Read StereoSeq `file` as [`GridCounts`](@ref).
 """
 function readstereoseq(file)
     df = readGEMfile(file)
+    transform!(df, :geneID => (x -> map(y -> convert(String, y), x; pure=true)) => :geneID)
     return GridCounts(df)
 end