diff --git a/src/RCPCHChart/RCPCHChart.stories.tsx b/src/RCPCHChart/RCPCHChart.stories.tsx
index 5dbdcbc..a173701 100644
--- a/src/RCPCHChart/RCPCHChart.stories.tsx
+++ b/src/RCPCHChart/RCPCHChart.stories.tsx
@@ -79,6 +79,26 @@ export const CentileChartUKWHOGirlsHeightWithMeasurementsLegend: Story = {
     },
 };
 
+export const CentileChartUKWHOBoysHeightWithMeasurementsLegend: Story = {
+    args: {
+        title: 'Patient Name - Hospital Number',
+        measurementMethod: 'height',
+        reference: 'uk-who',
+        sex: 'male',
+        logoVariant: 'legend',
+        measurements: { height: [] },
+        midParentalHeightData: {},
+        enableZoom: true,
+        chartType: 'centile',
+        enableExport: false,
+        exportChartCallback: () => {},
+        theme: 'tanner1',
+        height: 800,
+        width: 1000,
+        customThemeStyles: {},
+    },
+};
+
 export const CentileChartPrematureUKWHOGirlsHeightWithMeasurementsLegend: Story = {
     args: {
         title: 'Patient Name - Hospital Number',
diff --git a/src/functions/labelIndexInterval.ts b/src/functions/labelIndexInterval.ts
index 43bbcd8..de7f34e 100644
--- a/src/functions/labelIndexInterval.ts
+++ b/src/functions/labelIndexInterval.ts
@@ -1,7 +1,7 @@
 export function labelIndexInterval(
     chartScaleType: 'prem' | 'infant' | 'smallChild' | 'biggerChild' = 'biggerChild',
     index: number,
-    reference: 'uk-who' | 'cdc' | 'trisomy-21' | 'trisomy-21-aap' | 'turner',
+    reference: 'uk-who' | 'cdc' | 'trisomy-21' | 'trisomy-21-aap' | 'turner' | 'who',
     measurementMethod: 'height' | 'weight' | 'bmi' | 'ofc',
 ): boolean {
     // returns true if index of data point in centile data array should be rendered