What does it mean to have a "variant" in the gene for Alkaptonuria?

A variant is a change in the DNA sequence that is different that what is considered to be "normal." A pathogenic variant is one that has been found to cause disease. The HGD gene currently has over 130 pathogenic variants identified. If you have two known pathogenic variants, this is consistent with a diagnosis of Alkaptonuria. Having one is associated with being an unaffected carrier. Occasionally genetic testing might find a variant that has not been previously seen, and this will be classifed as a "variant of unknown significance" (VUS). When a VUS is found it is not certain if this change is part of normal human genetic variation or if it is a change that will cause Alkaptonuria. Because the diagnosis of Alkaptonuria is based on clinical findings, a person who is identified to have a variant of unknown significance should base their medical management on the presence or absence of the clinical findings of Alkaptonuria.

Other Questions About Alkaptonuria

• Who else in my family should I test for Alkaptonuria?
• Where do I find other people with Alkaptonuria?
• What specialist doctors should I see with Alkaptonuria?
• What should I do if I do not have access to an Alkaptonuria specialist?
• What is the usual abbreviation for Alkaptonuria?