BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuHartnup disorderHartnup disorder is a genetic condition in which there is a defect in the transport of certain amino acids (such as tryptophan and histidine) by the small intestine and kidneys.Amino acidsAmino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or bro...Read Article Now Book Mark Article TryptophanTryptophan is an amino acid needed for normal growth in infants and for the production and maintenance of the body's proteins, muscles, enzymes, and ...Read Article Now Book Mark Article Causes Hartnup disorder is a metabolic condition involving amino acids. It is an inherited condition. This condition occurs due to non-working copies of the SLC6A19 gene. A child must inherit a copy of the variant gene from both parents to be seriously affected.The condition most often appears between ages 3 to 9 years. Symptoms Most people show no symptoms. If symptoms do occur, they most often appear in childhood and may include:Diarrhea Mood changes Nervous system (neurologic) problems, such as abnormal muscle tone and uncoordinated movements Red, scaly skin rash, usually when skin is exposed to sunlight Skin rashRashes involve changes in the color, feeling or texture of your skin.Read Article Now Book Mark Article Sensitivity to light (photosensitivity) Short statureShort statureA child who has short stature is much shorter than children who are the same age and sex. Your health care provider will go over your child's growth ...Read Article Now Book Mark Article Exams and Tests The health care provider will order a urine test to check for high levels of neutral amino acids. The levels of other amino acids may be normal.Your provider can test for the gene that causes this condition. Biochemical tests may also be ordered. Treatment Treatments include:Avoiding sun exposure by wearing protective clothing and using a sunscreen with a protection factor of 15 or higher Eating a high-protein diet Taking supplements containing nicotinamide Undergoing mental health treatment, such as taking antidepressants or mood stabilizers, if mood swings or other mental health problems occur Outlook (Prognosis) Most people with this disorder can expect to live a normal life with no disability. Rarely, there have been reports of severe nervous system disease and even deaths in families with this disorder. Possible Complications In most cases, there are no complications. Complications when they occur may include:Changes in skin color that are permanent Mental health problems Rash Uncoordinated movementsNervous system symptoms can most often be reversed. However, in rare cases they can be severe or life threatening. When to Contact a Medical Professional Contact your provider if you have symptoms of this condition, especially if you have a family history of Hartnup disorder. Genetic counseling is recommended if you have a personal or family history of this condition and are planning a pregnancy. Prevention Genetic counseling prior to marriage and conception may help prevent some cases. Eating a high-protein diet may prevent amino acid deficiencies that cause symptoms.Open ReferencesReferencesKliegman RM, St. Geme JW, Blum NJ, et al. Defects in metabolism of amino acids. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2020:chap 105.Pearl PL, DiBacco ML, Gibson KM. Inborn errors of metabolism and the nervous system. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 91.AllVideoImagesTogRelated Information Tryptophan(Special Topic)Amino acids(Special Topic)Movement - uncoordinated(Symptoms)Depression(Symptoms)Depression - InDepth(In-Depth) Review Date: 8/18/2024 Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. 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Hartnup disorderHartnup disorder is a genetic condition in which there is a defect in the transport of certain amino acids (such as tryptophan and histidine) by the small intestine and kidneys.Amino acidsAmino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or bro...Read Article Now Book Mark Article TryptophanTryptophan is an amino acid needed for normal growth in infants and for the production and maintenance of the body's proteins, muscles, enzymes, and ...Read Article Now Book Mark Article Causes Hartnup disorder is a metabolic condition involving amino acids. It is an inherited condition. This condition occurs due to non-working copies of the SLC6A19 gene. A child must inherit a copy of the variant gene from both parents to be seriously affected.The condition most often appears between ages 3 to 9 years. Symptoms Most people show no symptoms. If symptoms do occur, they most often appear in childhood and may include:Diarrhea Mood changes Nervous system (neurologic) problems, such as abnormal muscle tone and uncoordinated movements Red, scaly skin rash, usually when skin is exposed to sunlight Skin rashRashes involve changes in the color, feeling or texture of your skin.Read Article Now Book Mark Article Sensitivity to light (photosensitivity) Short statureShort statureA child who has short stature is much shorter than children who are the same age and sex. Your health care provider will go over your child's growth ...Read Article Now Book Mark Article Exams and Tests The health care provider will order a urine test to check for high levels of neutral amino acids. The levels of other amino acids may be normal.Your provider can test for the gene that causes this condition. Biochemical tests may also be ordered. Treatment Treatments include:Avoiding sun exposure by wearing protective clothing and using a sunscreen with a protection factor of 15 or higher Eating a high-protein diet Taking supplements containing nicotinamide Undergoing mental health treatment, such as taking antidepressants or mood stabilizers, if mood swings or other mental health problems occur Outlook (Prognosis) Most people with this disorder can expect to live a normal life with no disability. Rarely, there have been reports of severe nervous system disease and even deaths in families with this disorder. Possible Complications In most cases, there are no complications. Complications when they occur may include:Changes in skin color that are permanent Mental health problems Rash Uncoordinated movementsNervous system symptoms can most often be reversed. However, in rare cases they can be severe or life threatening. When to Contact a Medical Professional Contact your provider if you have symptoms of this condition, especially if you have a family history of Hartnup disorder. Genetic counseling is recommended if you have a personal or family history of this condition and are planning a pregnancy. Prevention Genetic counseling prior to marriage and conception may help prevent some cases. Eating a high-protein diet may prevent amino acid deficiencies that cause symptoms.Open ReferencesReferencesKliegman RM, St. Geme JW, Blum NJ, et al. Defects in metabolism of amino acids. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2020:chap 105.Pearl PL, DiBacco ML, Gibson KM. Inborn errors of metabolism and the nervous system. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 91.
