diff --git a/misc/combination/combine-catvars.py b/misc/combination/combine-catvars.py
new file mode 100644
index 0000000..7bb4c1b
--- /dev/null
+++ b/misc/combination/combine-catvars.py
@@ -0,0 +1,149 @@
+"""
+This script is for combining newline-delimited JSON files from a Google Cloud Storage bucket into one file and uploading it back to the bucket.
+
+The input JSON objects are also parsed and the values from .rec.<id> are used as the final output objects written to the output file.
+
+e.g.:
+{"rec": {"12345": {"key1": "value1", "key2": "value2"}}}
+
+becomes:
+
+{"key1": "value1", "key2": "value2"}
+"""
+
+import gzip
+import json
+import os
+import re
+import time
+from dataclasses import dataclass
+
+from google.cloud import storage
+
+
+@dataclass()
+class Env:
+    bucket_name: str
+    folder_path: str
+    file_pattern: str
+    output_file_path: str
+    output_blob_path: str
+
+    def __init__(self):
+        self.bucket_name = os.getenv("bucket_name")
+        self.folder_path = os.getenv("folder_path")
+        self.file_pattern = os.getenv("file_pattern")
+        self.output_file_path = os.getenv("output_file_path")
+        self.output_blob_path = os.getenv("output_blob_path")
+
+
+# def _open(file_path, mode):
+#     if file_path.startswith("gs://"):
+#         return storage.open(file_path, mode)
+
+#     if file_path.endswith(".gz"):
+#         return gzip.open(file_path, mode)
+#     return open(file_path, mode)
+
+
+def combine_files(
+    bucket_name, folder_path, file_pattern, output_file_path, output_blob_path=None
+):
+    # Initialize Google Cloud Storage client
+    client = storage.Client()
+
+    # Get the bucket
+    bucket = client.get_bucket(bucket_name)
+
+    if bucket is None:
+        print(f"{bucket_name} bucket not found.")
+        return
+
+    # List all files in the folder matching the file pattern
+    blobs = bucket.list_blobs(prefix=folder_path)
+
+    if blobs is None:
+        print(f"No blobs found in {folder_path}.")
+        return
+
+    # log the blobs
+    blobs = list(blobs)
+    for blob in blobs:
+        print(f"Blob: {blob.name}")
+
+    files_to_combine = [
+        blob.name
+        for blob in blobs
+        if re.match(file_pattern, os.path.basename(blob.name))
+    ]
+
+    if len(files_to_combine) == 0:
+        print(f"No files found matching pattern {file_pattern} to combine.")
+        return
+
+    # Logging stuff
+    output_keys_count = 0
+    last_logged_output_count_time = time.time()
+    last_logged_output_count_value = 0
+
+    with gzip.open(output_file_path, "wt") as f_out:
+        # Iterate over each file
+        for file_name in files_to_combine:
+            print(f"Processing file: {file_name}")
+            blob = bucket.get_blob(file_name)
+            with gzip.open(blob.open("rb"), "rt") as f_in:
+                for i, line in enumerate(f_in):
+                    obj = json.loads(line)
+                    assert len(obj) == 1, (
+                        f"row {i} of file {file_name} had more than 1 key! ({len(obj)} keys) {obj}"
+                    )
+                    obj = obj["rec"]
+                    assert len(obj) == 1, (
+                        f"row {i} of file {file_name} had more than 1 key! ({len(obj)} keys) {obj}"
+                    )
+                    obj = obj[list(obj.keys())[0]]
+
+                    f_out.write(json.dumps(obj))
+                    f_out.write("\n")
+
+                    # Progress logging
+                    output_keys_count += 1
+                    now = time.time()
+                    if now - last_logged_output_count_time > 5:
+                        new_lines = output_keys_count - last_logged_output_count_value
+                        print(
+                            f"Output keys written: {output_keys_count} ({new_lines / 5:.2f} lines/s)"
+                        )
+                        last_logged_output_count_value = output_keys_count
+                        last_logged_output_count_time = now
+
+        f_out.write("\n")
+
+    print(f"Combined file {output_file_path} created successfully.")
+
+    if output_blob_path:
+        # Upload the combined file to the output_blob_uri
+        blob = bucket.blob(output_blob_path)
+        blob.upload_from_filename(output_file_path)
+
+        print(f"Combined file {output_file_path} uploaded to {output_blob_path}.")
+
+
+if __name__ == "__main__":
+    # app.run(debug=True, host="0.0.0.0")
+    env = Env()
+    print(
+        f"bucket_name: {env.bucket_name}, "
+        f"folder_path: {env.folder_path}, "
+        f"file_pattern: {env.file_pattern}, "
+        f"output_file_path: {env.output_file_path}, "
+        f"output_blob_path: {env.output_blob_path}"
+    )
+
+    combine_files(
+        bucket_name=env.bucket_name,
+        folder_path=env.folder_path,
+        file_pattern=env.file_pattern,
+        output_file_path=env.output_file_path,
+        output_blob_path=env.output_blob_path,
+    )
diff --git a/misc/combination/run-combine-catvars.bash b/misc/combination/run-combine-catvars.bash
new file mode 100644
index 0000000..55c873e
--- /dev/null
+++ b/misc/combination/run-combine-catvars.bash
@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+# get the parent directory of this script and refer to combine-catvars.py
+
+script="$(dirname "$(realpath "$0")")/combine-catvars.py"
+
+echo "$script"
+
+if [ ! -f "$script" ]; then
+    echo "Script not found: $script"
+    exit 1
+fi
+
+# input files: clinvar-gk-pilot/2025-03-23/dev/final_out/json
+# Don't use leading or trailing slashes in paths
+export bucket_name=clinvar-gk-pilot
+export folder_path=2025-03-23/dev/final_out/json
+export file_pattern=".*.json.gz"
+export output_file_path="final_out-combined.ndjson.gz"
+export output_blob_path=2025-03-23/dev/final_out-combined.ndjson.gz
+
+python ${script}