diff --git a/src/renderers/dom/fiber/ReactDOMFiberComponent.js b/src/renderers/dom/fiber/ReactDOMFiberComponent.js
index 346e4091d20..241e194377b 100644
--- a/src/renderers/dom/fiber/ReactDOMFiberComponent.js
+++ b/src/renderers/dom/fiber/ReactDOMFiberComponent.js
@@ -928,8 +928,10 @@ var ReactDOMFiberComponent = {
       var extraAttributeNames: Set<string> = new Set();
       var attributes = domElement.attributes;
       for (var i = 0; i < attributes.length; i++) {
-        // TODO: Do we need to lower case this to get case insensitive matches?
-        var name = attributes[i].name;
+        // Downcase to work around IE Edge, which reports some SVG attributes
+        // in all-caps. See:
+        // https://github.com/facebook/react/pull/10394#issuecomment-320523369
+        var name = attributes[i].name.toLowerCase();
         switch (name) {
           // Built-in attributes are whitelisted
           // TODO: Once these are gone from the server renderer, we don't need
@@ -1024,7 +1026,7 @@ var ReactDOMFiberComponent = {
           DOMProperty.isCustomAttribute(propKey)
         ) {
           // $FlowFixMe - Should be inferred as not undefined.
-          extraAttributeNames.delete(propKey);
+          extraAttributeNames.delete(propKey.toLowerCase());
           serverValue = DOMPropertyOperations.getValueForAttribute(
             domElement,
             propKey,
diff --git a/src/renderers/dom/shared/__tests__/ReactDOMServerIntegration-test.js b/src/renderers/dom/shared/__tests__/ReactDOMServerIntegration-test.js
index 2f7c137cbb1..03f49ebc35d 100644
--- a/src/renderers/dom/shared/__tests__/ReactDOMServerIntegration-test.js
+++ b/src/renderers/dom/shared/__tests__/ReactDOMServerIntegration-test.js
@@ -624,6 +624,12 @@ describe('ReactDOMServerIntegration', () => {
         const e = await render(<div className={null} />);
         expect(e.hasAttribute('className')).toBe(false);
       });
+
+      itRenders('no lower case classname', async render => {
+        const e = await render(<div classname="test" />, 1);
+        expect(e.hasAttribute('className')).toBe(false);
+        expect(e.hasAttribute('class')).toBe(false);
+      });
     });
 
     describe('htmlFor property', function() {
@@ -789,6 +795,11 @@ describe('ReactDOMServerIntegration', () => {
         expect(e.getAttribute('data-foo')).toBe('bar');
       });
 
+      itRenders('unknown data- attributes with casing', async render => {
+        const e = await render(<div data-myAttribute="test" />, 0);
+        expect(e.getAttribute('data-myAttribute')).toBe('test');
+      });
+
       itRenders('no unknown data- attributes with null value', async render => {
         const e = await render(<div data-foo={null} />);
         expect(e.hasAttribute('data-foo')).toBe(false);