diff --git a/chew/common.py b/chew/common.py
index 01d052a..07dd9fb 100644
--- a/chew/common.py
+++ b/chew/common.py
@@ -125,9 +125,11 @@ class Site:
     alt: str
 
 
-def load_sites(genome_release: str) -> typing.List[Site]:
+def load_sites(genome_release: str, sites_suffix: str) -> typing.List[Site]:
     logger.info("Loading sites .bed.gz for %s", genome_release)
-    path_gz = os.path.join(os.path.dirname(__file__), "data", f"{genome_release}_sites.bed.gz")
+    path_gz = os.path.join(
+        os.path.dirname(__file__), "data", f"{genome_release}_{sites_suffix}.bed.gz"
+    )
     result = []
     with gzip.open(path_gz, "rt") as inputf:
         for line in inputf:
diff --git a/chew/data/GRCh37_sitesX.bed.gz b/chew/data/GRCh37_sitesX.bed.gz
index 5320024..325c543 100644
Binary files a/chew/data/GRCh37_sitesX.bed.gz and b/chew/data/GRCh37_sitesX.bed.gz differ
diff --git a/chew/data/GRCh38_sitesX.bed.gz b/chew/data/GRCh38_sitesX.bed.gz
index 555372b..d4a5d44 100644
Binary files a/chew/data/GRCh38_sitesX.bed.gz and b/chew/data/GRCh38_sitesX.bed.gz differ
diff --git a/chew/fingerprint.py b/chew/fingerprint.py
index 53aca73..10644d6 100644
--- a/chew/fingerprint.py
+++ b/chew/fingerprint.py
@@ -178,7 +178,7 @@ def snps_step_call(
     logger.info("Reading sites BED (%s)...", bed_file)
     sites = {
         "%s%s:%s" % (chr_prefix, site.chrom, site.pos): (0, 0, float("nan"))
-        for site in load_sites(genome_release)
+        for site in load_sites(genome_release, sites_suffix)
     }
     logger.info("Converting VCF to fingerprint...")
     with vcfpy.Reader.from_path(path_calls) as vcf_reader:
@@ -346,7 +346,7 @@ def run(config: Config):
     else:
         samtools_idxstats_out = None
 
-    if config.step_bcftools_roh:
+    if config.step_bcftools_roh and autosomal_fingerprint is not None:
         roh_txt_contents = bcftools_roh_step(
             sample=sample, release=genome_release, autosomal_fingerprint=autosomal_fingerprint
         )
diff --git a/chew/roh.py b/chew/roh.py
index b253fad..c77ff4e 100644
--- a/chew/roh.py
+++ b/chew/roh.py
@@ -53,7 +53,7 @@ def create_vcf_header(sample: str, release: str) -> vcfpy.Header:
 def write_vcf(tmpdir: str, sample: str, release: str, autosomal_fingerprint) -> str:
     logger.info("Constructing VCF header...")
     vcf_header = create_vcf_header(sample, release)
-    sites = load_sites(release)
+    sites = load_sites(release, "sites")
     autosomal_mask = autosomal_fingerprint[0]
     autosomal_is_alt = autosomal_fingerprint[1]
     autosomal_hom_alt = autosomal_fingerprint[2]
diff --git a/chew/stats.py b/chew/stats.py
index b7eff8b..07c5208 100644
--- a/chew/stats.py
+++ b/chew/stats.py
@@ -109,9 +109,14 @@ def compute_sample_stats(container) -> SampleStats:
     header = extract_header(container)
 
     autosomal_fingerprint = container["autosomal_fingerprint"]
-    autosomal_mask = autosomal_fingerprint[0]
-    autosomal_is_alt = autosomal_fingerprint[1]
-    autosomal_hom_alt = autosomal_fingerprint[2]
+    if autosomal_fingerprint:
+        autosomal_mask = autosomal_fingerprint[0]
+        autosomal_is_alt = autosomal_fingerprint[1]
+        autosomal_hom_alt = autosomal_fingerprint[2]
+    else:
+        autosomal_mask = np.zeros(0, dtype=bool)
+        autosomal_is_alt = np.zeros(0, dtype=bool)
+        autosomal_hom_alt = np.zeros(0, dtype=bool)
 
     if "autosomal_aafs" in header.fields:
         var_het = compute_autosomal_aafs(container)
diff --git a/requirements/base.txt b/requirements/base.txt
index cc5e100..5de11ed 100644
--- a/requirements/base.txt
+++ b/requirements/base.txt
@@ -1,11 +1,12 @@
+attrs
+cattrs
+click
 logzero
-tqdm
 numpy
-vcfpy
-pysam
 pandas
 plotly
+pyarrow
+pysam
 scipy
-click
-attrs
-cattrs
+tqdm
+vcfpy
diff --git a/tests/test_run_fingerprint.py b/tests/test_run_fingerprint.py
index b51a0e2..9e8695b 100644
--- a/tests/test_run_fingerprint.py
+++ b/tests/test_run_fingerprint.py
@@ -25,7 +25,7 @@ def test_smoke_test_run_fingerprint(cli_runner, path_tests, tmpdir):
             "--input-bam",
             str(path_tests / "data" / "igsr.HG00102.TP73.bam"),
             "--output-fingerprint",
-            str(tmpdir / "out"),
+            str(tmpdir / "out.npz"),
         ],
     )
 
@@ -59,7 +59,7 @@ def test_smoke_test_run_fingerprint(cli_runner, path_tests, tmpdir):
 def test_fingerprint_bam_grch37(
     cli_runner: CliRunner, tmpdir: LocalPath, path_tests: Path, path_ref: str, path_bam: str
 ):
-    cli_runner.invoke(
+    result = cli_runner.invoke(
         cli,
         [
             "fingerprint",
@@ -68,9 +68,10 @@ def test_fingerprint_bam_grch37(
             "--input-bam",
             path_bam,
             "--output-fingerprint",
-            str(tmpdir / "out"),
+            str(tmpdir / "out.npz"),
         ],
     )
+    assert result.exit_code == 0, result
 
     # Check that output path exists and is similar to all finger prints.
     output = tmpdir / "out.npz"