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  3. Crigler-Najjar syndrome type 2
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Crigler-Najjar syndrome type 2


Title


Other Names:
Crigler-Najjar syndrome, type II; Crigler Najjar syndrome type 2; Arias syndrome
Categories:
Congenital and Genetic Diseases; Digestive Diseases; Metabolic disorders

Summary Summary


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Crigler-Najjar syndrome type 2 (CN-2) is a rare disorder that causes elevated levels of bilirubin in the blood (hyperbilirubinemia). Bilirubin normally is made by the body when old red blood cells are broken down. However, people with CN-2 develop hyperbilirubinemia even when red blood cells are not excessively broken down, because they have too little of a liver enzyme needed for conversion and excretion of bilirubin.[1][2][3]

The main symptom of CN-2 is persistent jaundice, which is yellowing of the skin, mucous membranes and whites of the eyes. Jaundice may become noticeable in infancy (particularly when an infant is sick or has not eaten for an extended time), but some people with CN-2 are not diagnosed until adulthood. Rarely, a person with CN-2 may develop bilirubin encephalopathy (also called kernicterus), especially during illness, prolonged fasting, or while under anesthesia.[1][2][3]

CN-2 is caused by mutations in the UGT1A1 gene and inheritance is autosomal recessive. CN-2 responds to treatment with phenobarbital; however during an episode of severe hyperbilirubinemia, phototherapy may be needed. Not all people with CN-2 require treatment, but routine monitoring is still recommended.[1][2][4]

Of note, mutations in the UGT1A1 gene can alternatively cause other disorders, such as Crigler-Najjar syndrome type 1 (CN-1) and Gilbert syndrome. CN-1 is characterized by near or complete absence of enzyme activity (versus partial absence in type 2) and severe, life-threatening symptoms. Phenobarbitol treatment is ineffective for people with CN-1, which is treated differently.[1][2][3] Gilbert syndrome is considered a mild liver disorder that often does not cause symptoms or causes mild jaundice.[2][5] Sometimes it can be hard to distinguish between Gilbert syndrome and CN-2 because of considerable overlap in measured bilirubin levels. Genetic testing to identify the specific mutation present is sometimes needed for the correct diagnosis.[5]
Last updated: 8/27/2018

Symptoms Symptoms


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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.

Showing of 5 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Neonatal hyperbilirubinemia 0003265
Prolonged neonatal jaundice
Prolonged yellowing of skin in newborn
0006579
Unconjugated hyperbilirubinemia 0008282
Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance 0000007
Jaundice
Yellow skin
Yellowing of the skin
[ more ]
0000952
Showing of 5 |
Do you have more information about symptoms of this disease? We want to hear from you.
Last updated: 2/1/2019
Do you have updated information on this disease? We want to hear from you.

Diagnosis Diagnosis


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Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • Orphanet lists international laboratories offering diagnostic testing for this condition.

Find a Specialist Find a Specialist


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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

  • To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.

Related Diseases Related Diseases


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Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes disorders of excessive bilirubin production (hemolysis) and impaired hepatic handling of bilirubin (hepatitis and Gilbert syndrome; see this term). CNS2 can be differentiated from CNS1 by measurement of transferase activity and the response to phenobarbital treatment.
Visit the Orphanet disease page for more information.

Research Research


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Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • Orphanet lists European clinical trials, research studies, and patient registries enrolling people with this condition. 

Organizations Organizations


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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

  • Metabolic Support UK
    5 Hilliards Court
    Sandpiper Way
    Chester Business Park
    Chester, CH4 9QP United Kingdom
    Toll-free: 0800 652 3181
    Telephone: 0845 241 2173
    E-mail: https://www.metabolicsupportuk.org/contact-us
    Website: https://www.metabolicsupportuk.org
  • The Crigler Najjar Association (USA)
    3134 Bayberry Street
    CNA / King’s Way Foundation
    c/o Cory Mauck
    Witchita, KS 67226
    E-mail: mauckc@msn.com
    Website: http://criglernajjar.altervista.org/treregistry.htm

Organizations Providing General Support

  • American Association for the Study of Liver Diseases
    1001 North Fairfax, 4th floor
    Alexandria, VA 22314
    Telephone: 703–299–9766
    Fax: 703–299–9622
    E-mail: aasld@aasld.org
    Website: http://www.aasld.org/
  • American Liver Foundation
    39 Broadway, Suite 2700
    New York, NY 10006
    Toll-free: +1-800-465-4837 (Helpline)
    Telephone: +1-212-668-1000
    E-mail: https://liverfoundation.org/for-patients/contact-us/
    Website: https://liverfoundation.org/
Do you know of an organization? We want to hear from you.

Learn More Learn More


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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.

Where to Start

  • Genetics Home Reference (GHR) contains information on Crigler-Najjar syndrome type 2. This website is maintained by the National Library of Medicine.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • 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 Crigler-Najjar syndrome type 2. Click on the link to view a sample search on this topic.

Selected Full-Text Journal Articles

  • Labrune P. Crigler-Najjar syndrome. Orphanet Encyclopedia. 2004 Jan.

News & Events News & Events


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News

  • NIH Hosts Rare Disease Day Event, Twitter Chat
    January 24, 2019

GARD Answers GARD Answers


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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.

Have a question? Contact a GARD Information Specialist.

References References


  1. Crigler Najjar Syndrome. National Organization for Rare Disorders (NORD). 2016; https://rarediseases.org/rare-diseases/crigler-najjar-syndrome/.
  2. Gilbert Syndrome. National Organization for Rare Disorders (NORD). 2015; https://rarediseases.org/rare-diseases/gilbert-syndrome/.
  3. Crigler-Najjar syndrome. Genetics Home Reference (GHR). February, 2012; https://ghr.nlm.nih.gov/condition/crigler-najjar-syndrome.
  4. Roy-Chowdhury N, Roy-Chowdhury J. Crigler-Najjar syndrome. UpToDate. Waltham, MA: UpToDate; June 2, 2016; https://www.uptodate.com/contents/crigler-najjar-syndrome.
  5. Wagner K-H, Shiels RG, Lang CA, Khoei NS, Bulmer AC. Diagnostic criteria and contributors to Gilbert’s syndrome. Critical Reviews in Clinical Laboratory Sciences. 2018; 55(2):129-139. https://www.ncbi.nlm.nih.gov/pubmed/29390925.
Do you know of a review article? We want to hear from you.
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rare disease research!
You can help advance rare disease research!
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