diff --git a/ts/core/MmlTree/MmlVisitor.ts b/ts/core/MmlTree/MmlVisitor.ts
index e970240c5..119017ed5 100644
--- a/ts/core/MmlTree/MmlVisitor.ts
+++ b/ts/core/MmlTree/MmlVisitor.ts
@@ -138,8 +138,12 @@ export class MmlVisitor extends AbstractVisitor<MmlNode> {
       node.attributes.getAllAttributes()
     ) as PropertyList;
     const variants = CLASS.variants;
-    if (attributes.hasOwnProperty('mathvariant') && variants.hasOwnProperty(attributes.mathvariant as string)) {
-      attributes.mathvariant = variants[attributes.mathvariant as string];
+    if (attributes.hasOwnProperty('mathvariant')) {
+      if (variants.hasOwnProperty(attributes.mathvariant as string)) {
+        attributes.mathvariant = variants[attributes.mathvariant as string];
+      } else if (node.getProperty('ignore-variant')) {
+        delete attributes.mathvariant;
+      }
     }
     return attributes;
   }
@@ -154,7 +158,8 @@ export class MmlVisitor extends AbstractVisitor<MmlNode> {
     const data = {} as PropertyList;
     const variant = node.attributes.getExplicit('mathvariant') as string;
     const variants = (this.constructor as typeof MmlVisitor).variants;
-    variant && variants.hasOwnProperty(variant) && this.setDataAttribute(data, 'variant', variant);
+    variant && (node.getProperty('ignore-variant') || variants.hasOwnProperty(variant)) &&
+      this.setDataAttribute(data, 'variant', variant);
     node.getProperty('variantForm') && this.setDataAttribute(data, 'alternate', '1');
     node.getProperty('pseudoscript') && this.setDataAttribute(data, 'pseudoscript', 'true');
     node.getProperty('autoOP') === false && this.setDataAttribute(data, 'auto-op', 'false');
diff --git a/ts/input/tex/TexParser.ts b/ts/input/tex/TexParser.ts
index f5d518ead..518b9926e 100644
--- a/ts/input/tex/TexParser.ts
+++ b/ts/input/tex/TexParser.ts
@@ -525,7 +525,13 @@ export default class TexParser {
    * @return {MmlNode} The newly created node.
    */
   public create(kind: string, ...rest: any[]): MmlNode {
-    return this.configuration.nodeFactory.create(kind, ...rest);
+    const node = this.configuration.nodeFactory.create(kind, ...rest);
+    if (node.isToken && node.attributes.hasExplicit('mathvariant')) {
+      if ((node.attributes.get('mathvariant') as string).charAt(0) === '-') {
+        node.setProperty('ignore-variant', true);
+      }
+    }
+    return node;
   }
 
   /**
diff --git a/ts/output/common/FontData.ts b/ts/output/common/FontData.ts
index 14f5614eb..6e7aa8cb9 100644
--- a/ts/output/common/FontData.ts
+++ b/ts/output/common/FontData.ts
@@ -332,8 +332,8 @@ export interface FontExtensionData<C extends CharOptions, D extends DelimiterDat
 /**
  * Merge options into an object or array.
  */
-export function mergeOptions(dst: OptionList, src: OptionList) {
-  return (src ? defaultOptions([dst], [src])[0] : dst);
+export function mergeOptions(obj: OptionList, dst: string, src: OptionList) {
+  return (src ? defaultOptions(obj, {[dst]: src})[dst] : obj[dst]);
 }
 
 /****************************************************************************/
@@ -806,7 +806,7 @@ export class FontData<C extends CharOptions, V extends VariantData<C>, D extends
       ['sizeVariants', 'defaultSizeVariants'],
       ['stretchVariants', 'defaultStretchVariants']
     ] as [keyof FontExtensionData<CharOptions, DelimiterData>, keyof typeof FontData][]) {
-      mergeOptions(this[dst] as OptionList, data[src] as OptionList);
+      mergeOptions(this, dst, data[src] as OptionList);
     }
     if (data.delimiters) {
       Object.assign(this.defaultDelimiters, data.delimiters);
@@ -843,7 +843,7 @@ export class FontData<C extends CharOptions, V extends VariantData<C>, D extends
    * @param {OptionList} options   The options to merge into the font options
    */
   public setOptions(options: OptionList) {
-    mergeOptions(this.options, options);
+    defaultOptions(this.options, options);
   }
 
   /**
@@ -864,12 +864,12 @@ export class FontData<C extends CharOptions, V extends VariantData<C>, D extends
 
     defaultOptions(this.options, data.options || {});
     defaultOptions(this.params, data.parameters || {});
-    this.sizeVariants = mergeOptions(this.sizeVariants, data.sizeVariants);
-    this.stretchVariants = mergeOptions(this.stretchVariants, data.stretchVariants);
-    this.defineCssFonts(mergeOptions([], data.cssFonts));
-    this.createVariants(mergeOptions([], data.variants));
+    mergeOptions(this, 'sizeVariants', data.sizeVariants);
+    mergeOptions(this, 'stretchVariants', data.stretchVariants);
+    this.defineCssFonts(mergeOptions({cssFonts: {}}, 'cssFonts', data.cssFonts));
+    this.createVariants(mergeOptions({variants: []}, 'variants', data.variants));
     if (data.delimiters) {
-      this.defineDelimiters(mergeOptions([], data.delimiters));
+      this.defineDelimiters(mergeOptions({delimiters: {}}, 'delimiters', data.delimiters));
       this.CLASS.adjustDelimiters(this.delimiters, Object.keys(data.delimiters),
                                   dynamicFont.sizeN, dynamicFont.stretchN);
     }
diff --git a/ts/output/svg/FontData.ts b/ts/output/svg/FontData.ts
index 6af974f48..83a96258e 100644
--- a/ts/output/svg/FontData.ts
+++ b/ts/output/svg/FontData.ts
@@ -21,7 +21,8 @@
  * @author dpvc@mathjax.org (Davide Cervone)
  */
 
-import {CharMap, CharOptions, CharDataArray, VariantData, DelimiterData, FontData} from '../common/FontData.js';
+import {CharMap, CharOptions, CharDataArray, VariantData, DelimiterData,
+        FontData, FontExtensionData, mergeOptions} from '../common/FontData.js';
 export * from '../common/FontData.js';
 
 export type CharStringMap = {[name: number]: string};
@@ -54,6 +55,15 @@ export interface SvgDelimiterData extends DelimiterData {
 }
 
 
+/**
+ * Includes the data needed for SVG font extensions
+ */
+export interface SvgFontExtensionData<C extends SvgCharOptions, D extends SvgDelimiterData>
+extends FontExtensionData<C, D> {
+  cacheIds: {[variant: string]: string}
+}
+
+
 /****************************************************************************/
 
 /**
@@ -81,6 +91,17 @@ export class SvgFontData extends FontData<SvgCharOptions, SvgVariantData, SvgDel
     return super.charOptions(font, n) as SvgCharOptions;
   }
 
+  /**
+   * @override
+   */
+  public static addExtension(
+    data: SvgFontExtensionData<SvgCharOptions, SvgDelimiterData>,
+    prefix: string = ''
+  ) {
+    super.addExtension(data, prefix);
+    mergeOptions(this, 'variantCacheIds', data.cacheIds);
+  }
+
 }
 
 export type SvgFontDataClass = typeof SvgFontData;