Cookies help us deliver our services. By using our services, you agree to our use of cookies. Learn more

Alkaptonuria

What is Alkaptonuria?

Alkaptonuria is a rare genetic metabolic disease, characterized by the accumulation of acid in various tissues. Those affected by the disease do not have an enzyme that can break down homogentisic acid (HGA). This acid leads to darker urine and alkalization, which occurs when a compound turns into a base. Other characteristic symptoms are black pigmentation of cartilage and tissues; arthritis can also occur especially in the spine.

 

Synonyms

  • alcaptonuria

Alkaptonuria is a rare genetic metabolic disease, characterized by the accumulation of acid in various tissues. Those affected by the disease do not have an enzyme that can break down homogentisic acid (HGA). This acid leads to darker urine and alkalization, which occurs when a compound turns into a base. Other characteristic symptoms are black pigmentation of cartilage and tissues; arthritis can also occur especially in the spine.

Special thanks to: 

Writer: Sissi Wang, Research Associate, RareShare

Reviewer: Lakshminarayan Ranganath, MD, Royal Liverpool University Hospital, and co-founder and Medical Director of the Alkaptonuria Society in the UK.

Alkaptonuria affects both males and females equally and the condition is very rare. On average, there is about 1 case per 250,000 to 1,000,000 people, but the condition is more common where intermarriage is prevalent.

Name Abbreviation
alcaptonuria N/A

Alkaptonuria is an autosomal recessive disease. This means that individuals must have two copies of the abnormal gene for the same trait, one from the mother and one from the father. If an individual receives one normal gene and one affected gene, the person will become a carrier for the condition but not affected with it. This case is known as a heterozygous gene pattern. Thus, the risk for two carrier parents to pass to gene and produce an affected offspring is 25% per pregnancy. The risk of inheritance is the same for both males and females. The specific gene that is mutated in the case of this condition is the HGD gene. Normally, HGD contributes to the making of an enzyme called homogentisate dioxygenase, which is responsible for breaking down HGA. With the mutation, however, the acid can not be broken down properly and as a result, accumulates within the body.

The symptoms of alkaptonuria are progressive and generally do not appear until adulthood thus individuals can lead normal childhoods. Generally, urine is dark or turns black with exposure to air. Unusual pigmentation of the ear cartilage and of the sclera (white portion of the eye) may develop. Kidney stones and prostate stones may also form. The disorder also manifests joint pain, causing stiffness and in later stages can cause arthritis. Vertebrae and other bones may fuse together, leading to immobility, a condition called ankylosis. Cardiac complications may also arise, such as arrhythmias and aortic stenosis.

Diagnosis of alkaptonuria is based on patient history, identification of symptoms, and clinical tests. High levels of homogentisic acid in urine and its characteristic dark color indicate the presence of the disease.

In individuals over 40, echocardiography may be recommended to detect potential cardiac complications, such as aortic dilatation or calcification.

Gas chromatography-mass spectroscopy or LC-Tandem mass spectrometry is used to measure the levels of HGA in urine. Molecular genetic testing may also be used to confirm the diagnosis. The clinical impact of alkaptonuria may be assessed with spinal x-rays, to show the calcification of bones and joints; various imaging techniques, to assess joint problems as well as artery calcification; and echocardiography for cardiac complications.

Treatment for alkaptonuria is palliative. Dietary restrictions are beneficial in order to minimize the levels of acid accumulating in the body. Joint pain can be treated with paracetamol and nonsteroidal anti-inflammatory drugs. In severe cases, spinal surgery or joint replacement surgeries are required.

Life expectancy is not significantly reduced, unless cardiac complications arise.

Tips or Suggestions of Alkaptonuria has not been added yet.

Alkaptonuria. Genetics Home Reference website. http://ghr.nlm.nih.gov/condition/alkaptonuria

 

Alkaptonuria. Genetic and Rare Diseases Information Center website. https://rarediseases.info.nih.gov/gard/5775/alkaptonuria/case/31676/case-questions

 

Alkaptonuria; AKU. Online Mendelian Inheritance in Man website. http://omim.org/entry/203500?search=Alkaptonuria&highlight=alkaptonuria

 

Alkaptonuria. The National Organization for Rare Diseases website. http://rarediseases.org/rare-diseases/alkaptonuria/

 

Alkaptonuria. OrphaNet website. http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=56

Scientists hopeful about new alkaptonuria treatment Created by RareshareTeam
Last updated 8 Aug 2018, 12:03 AM

Posted by RareshareTeam
8 Aug 2018, 12:03 AM

In a recent study, 39 people with AKU were given 2 mg of nitisinone each day for three years. The results show that the drug helps to stop the progression of AKU.  Have you heard of ntisinone?  What other therapies - pharmacological or otherwise - do you use to manage your symptoms?

https://www.sciencedaily.com/releases/2018/08/180801102554.htm

alkaptonuria Created by ruthannhay
Last updated 17 Mar 2009, 04:11 PM

Posted by ruthannhay
17 Mar 2009, 04:11 PM

I have two children with Alkaptonuria, am curious to know if anyone is familiar with the disorder

Community External News Link
Title Date Link
Alkaptonuria: New treatment for ultra-rare disease, alkaptonuria 08/01/2018
Community Resources
Title Description Date Link

Clinical Trials


Cords registry

CoRDS, or the Coordination of Rare Diseases at Sanford, is based at Sanford Research in Sioux Falls, South Dakota. It provides researchers with a centralized, international patient registry for all rare diseases. This program allows patients and researchers to connect as easily as possible to help advance treatments and cures for rare diseases. The CoRDS team works with patient advocacy groups, individuals and researchers to help in the advancement of research in over 7,000 rare diseases. The registry is free for patients to enroll and researchers to access.

Enrolling is easy.

  1. Complete the screening form.
  2. Review the informed consent.
  3. Answer the permission and data sharing questions.

After these steps, the enrollment process is complete. All other questions are voluntary. However, these questions are important to patients and their families to create awareness as well as to researchers to study rare diseases. This is why we ask our participants to update their information annually or anytime changes to their information occur.

Researchers can contact CoRDS to determine if the registry contains participants with the rare disease they are researching. If the researcher determines there is a sufficient number of participants or data on the rare disease of interest within the registry, the researcher can apply for access. Upon approval from the CoRDS Scientific Advisory Board, CoRDS staff will reach out to participants on behalf of the researcher. It is then up to the participant to determine if they would like to join the study.

Visit sanfordresearch.org/CoRDS to enroll.

Community Leaders

 

Expert Questions

Ask a question

Community User List

This is the account for the RareShare team.

Recently diagnosed with Ochronosis. Looking for information, support, nutrition guidance, doctors and geneticist.

 

Wanting to share information and chat with other who have this disease.

...

I have two children with Alkaptonuria

Start a Community


Don't See Your Condition On Rareshare?

Start your own! With a worldwide network of 8,000 users, you won't be the only member of your community for long.

FAQ


Have questions about rareshare?

Visit our Frequently Asked Questions page to find the answers to some of the most commonly asked questions.

Discussion Forum

Scientists hopeful about new alkaptonuria treatment

Created by RareshareTeam | Last updated 8 Aug 2018, 12:03 AM

alkaptonuria

Created by ruthannhay | Last updated 17 Mar 2009, 04:11 PM


Communities

Our Communities

Join Rareshare to meet other people that have been touched by rare diseases. Learn, engage, and grow with our communities.

FIND YOUR COMMUNITY
Physicians

Our Resources

Our rare disease resources include e-books and podcasts

VIEW OUR EBOOKS

LISTEN TO OUR PODCASTS

VIEW OUR GUIDES

Leaders

Our Community Leaders

Community leaders are active users that have been touched by the rare disease that they are a part of. Not only are they there to help facilitate conversations and provide new information that is relevant for the group, but they are there for you and to let you know you have a support system on Rareshare.