Crigler-Najjar syndrome (Type I)

Crigler-Najjar syndrome (Type 1)
* This composite image of Crigler-Najjar Syndrome, Type I was created to help geneticists get a better analysis

What is Crigler-Najjar syndrome (Type I)?

Crigler-Najjar syndrome is a rare genetic syndrome that leads to the build-up of high levels of unconjugated bilirubin. This form of bilirubin is a toxic substance and causes the most serious symptoms of this syndrome.

There are two types of the syndrome: Type 1 is the severe form of the diseases, Type 2 is less severe and the symptoms are much milder.

Syndrome Synonyms:
Crigler-Najjar Syndrome; Hyperbilirubinemia, Crigler-Najjar Type I; HBLRCN1

What gene change causes Crigler-Najjar syndrome (Type 1)?

Mutations in the UGT1A1 gene are responsible for the syndrome. It is inherited in an autosomal recessive pattern.

Autosomal recessive inheritance means an affected individual receives one copy of a mutated gene from each of their parents, giving them two copies of a mutated gene. Parents, who carry only one copy of the gene mutation will not generally show any symptoms but have a 25% chance of passing the copies of the gene mutations onto each of their children.

What are the main symptoms of Crigler-Najjar syndrome (Type 1)?

The buildup of toxic unconjugated bilirubin in the blood can trigger kernicterus. This is a severe symptom in individuals with the Type 1 form of the syndrome. Kernicterus is a form of brain damage when the unconjugated bilirubin damages the nerves of the brain leading also to lethargy and hypotonia, as well as involuntary body movements, hearing issues and intellectual disability.

This buildup also causes jaundice, which is the yellowing of the skin and whites of the eyes.

Possible clinical traits/features:
Encephalopathy, Elevated hepatic transaminase, Hearing impairment, Memory impairment, Abnormality of the liver, Autosomal recessive inheritance, Seizure, Ophthalmoparesis, Jaundice, Kernicterus, Unconjugated hyperbilirubinemia.

How is it diagnosed?

To find out if someone has a diagnosis of Crigler-Najjar syndrome (Type 1), it is important to have a consultation and evaluation with a clinical genetic specialist.  Specialists may also suggest specific genetic testing or other types of tests to help reach a diagnosis.  FDNA’s AI technology can help speed up the diagnostic process by analyzing facial features and other health information.

Share this syndrome

Crigler-Najjar syndrome (Type 1)
* This composite image of Crigler-Najjar Syndrome, Type I was created to help geneticists get a better analysis

Share this syndrome

Other childhood syndromes

More syndromes

Syndromes & Disorders

Weiss-Kruszka syndrome (WSKA)

It is a multiple congenital anomaly syndrome that has been recently identified. There are just 24 potential cases currently reported worldwide. It is also known as Weiss-Kruska syndrome. The gene responsible for the disorder is the ZNF462 gene.

Read more
Syndromes & Disorders

Yunis-Varon syndrome (YVS)

It is a rare genetic disease that affects multiple systems of the body. Its main symptoms affect the skeletal and nervous systems, as well as ectodermal tissue (hair and teeth). Since 1980 just 25 cases from 19 families have been diagnosed and recorded. This syndrome is also known as: Cleidocranial Dysplasia With Micrognathia, Absent Thumbs, And Distal Aphalangia

Read more
Syndromes & Disorders

Xia-Gibbs syndrome (XIGIS)

It is a rare genetic syndrome associated mainly with intellectual disability. This syndrome is also known as: Mental Retardation, Autosomal Dominant 25; Mrd25 Changes in the AHDC1 gene are responsible for causing the syndrome. It is inherited in an autosomal dominant pattern, although all cases of the syndrome recorded so far have been the result of de novo or new mutations in the gene. In the case of autosomal dominant inheritance just one parent is the carrier of the gene mutation, and they have a 50% chance of passing it onto each of their children. Syndromes inherited in an autosomal dominant inheritance are caused by just one copy of the gene mutation. In some cases, a genetic syndrome may be the result of a de-novo mutation and the first case in a family. In this case, this is a new gene mutation which occurs during the reproductive process.

Read more