National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Hypertryptophanemia



Hypertryptophanemia is a rare condition that likely occurs due to abnormalities in the body's ability to process the amino acid (a building block of proteins), tryptophan. People affected by this condition may experience intellectual disability and behavioral problems (i.e. periodic mood swings, exaggerated emotional responses and abnormal sexual behavior).[1][2][3] The underlying genetic cause of hypertryptophanemia is currently unknown; however, it appears to be inherited in an autosomal recessive manner.[2] Treatment is based on the signs and symptoms present in each person.
Last updated: 1/13/2016

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Adducted thumb
Inward turned thumb
0001181
Aggressive behavior
Aggression
Aggressive behaviour
Aggressiveness
[ more ]
0000718
Autosomal recessive inheritance 0000007
Camptodactyly of finger
Permanent flexion of the finger
0100490
Depressivity
Depression
0000716
Emotional lability
Emotional instability
0000712
Generalized joint laxity
Hypermobility of all joints
0002761
Global developmental delay 0001263
Hypersexuality
Sex addiction
0030214
Hypertelorism
Wide-set eyes
Widely spaced eyes
[ more ]
0000316
Hypertryptophanemia
High blood tryptophan concentration
Increased tryptophan in blood
[ more ]
0500134
Intellectual disability, moderate
IQ between 34 and 49
0002342
Limited elbow extension
Decreased elbow extension
Elbow limited extension
Limitation of elbow extension
Limited extension at elbows
Limited forearm extension
Restricted elbow extension
[ more ]
0001377
Myopia
Close sighted
Near sighted
Near sightedness
Nearsightedness
[ more ]
0000545
Pes planus
Flat feet
Flat foot
[ more ]
0001763
Sensorineural hearing impairment 0000407
Strabismus
Cross-eyed
Squint
Squint eyes
[ more ]
0000486
Stuttering
Stammering
0025268
Tryptophanuria
High urine tryptophan levels
0003361
Visual impairment
Impaired vision
Loss of eyesight
Poor vision
[ more ]
0000505
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Last updated: 7/1/2020

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease


These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Hypertryptophanemia. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.


  1. Martin JR, Mellor CS, Fraser FC. Familial hypertryptophanemia in two siblings. Clin Genet. April 1995; 47(4):180-183.
  2. Hypertryptophanemia. Orphanet. June 2006; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=2224.
  3. HYPERTRYPTOPHANEMIA, FAMILIAL. OMIM. September 2014; http://www.omim.org/entry/600627.