Search for glossary terms (regular expression allowed)
Begin with Contains Exact termSounds like
All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Term Definition

An inherited condition that causes urine to turn black when exposed to air. Ochronosis, a build-up of dark pigment in connective tissues such as cartilage and skin, is also characteristic of the disorder. People with alkaptonuria typically develop arthritis in adulthood, particularly in the spine and large joints.

Alkaptonuria is caused by changes in the HDG gene which makes an enzyme that helps break down the amino acids phenylalanine and tyrosine. Alkaptonuria is inherited in an autosomal recessive pattern.

Definition from Genetics Home Reference, US National Library of Medicine: Alkaptonuria

Text Search

Tell us your story

We are always looking for new stories to add to this site, and are particularly keen to hear from more practitioners. Your colleagues can learn so much from how you’ve dealt with situations which involved genetics.

Contact Us

Tell us what you think

Your feedback is important in helping us to enhance this website. Please take a moment to complete the brief questionnaire.


Winners of the Association of Healthcare Communicators Best use of new media award 2009.
‘This was superb’ - Judge’s comment.


Betsi Cadwaladr Scholarship Foundation Joint Award Winners 2013.

Betsi Cadwaladr logo