North American Indian childhood cirrhosis is a rare liver disorder that occurs in children. The liver malfunction causes yellowing of the skin and whites of the eyes (jaundice) in affected infants. The disorder worsens with age, progressively damaging the liver and leading to chronic, irreversible liver disease (cirrhosis) in childhood or adolescence. Unless it is treated with liver transplantation, North American Indian childhood cirrhosis typically causes life-threatening complications including liver failure.

North American Indian childhood cirrhosis results from at least one known mutation in the UTP4 gene. This gene provides instructions for making a protein called cirhin, whose precise function is unknown. Within cells, cirhin is located in a structure called the nucleolus, which is a small region inside the nucleus where ribosomal RNA (rRNA) is produced. A chemical cousin of DNA, rRNA is a molecule that helps assemble protein building blocks (amino acids) into functioning proteins. Researchers believe that cirhin may play a role in processing rRNA. Studies also suggest that cirhin may function by interacting with other proteins.

Cirhin is found in many different types of cells, so it is unclear why the effects of North American Indian childhood cirrhosis appear to be limited to the liver. Researchers are working to determine how a UTP4 gene mutation causes the progressive liver damage characteristic of this disorder.

Normal Function

The UTP4 gene provides instructions for making a protein called cirhin, whose precise function is unknown. This protein is found in many different tissues and organs. Within cells, cirhin is located in a structure called the nucleolus, which is a small region inside the nucleus where ribosomal RNA (rRNA) is produced. A chemical cousin of DNA, rRNA is a molecule that helps assemble protein building blocks (amino acids) into functioning proteins. Researchers believe that cirhin may play a role in processing rRNA.

Studies also suggest that cirhin interacts with other proteins, and it may function as part of a protein complex (a group of proteins that work together). The significance of these protein interactions is unknown.

Health Conditions Related to Genetic Changes

North American Indian childhood cirrhosis

At least one mutation in the UTP4 gene has been found to cause North American Indian childhood cirrhosis, a chronic liver disease identified in a First Nation population in Quebec. The known mutation replaces the amino acid arginine with the amino acid tryptophan at protein position 565 (written as Arg565Trp or R565W). This genetic change likely alters the structure and function of cirhin. However, it is unclear why the effects of the UTP4 gene mutation are limited to the liver or how they cause the progressive liver damage characteristic of this disorder.

Other Names for This Gene

• CIR1A_HUMAN
• CIRH1A
• cirhin
• cirrhosis, autosomal recessive 1A (cirhin)
• FLJ14728
• FLJ17146
• KIAA1988
• NAIC
• testis expressed gene 292
• TEX292

Genomic Location

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

North American Indian childhood cirrhosis has been found only in children of Ojibway-Cree descent in the Abitibi region of northwestern Quebec, Canada. At least 30 affected individuals from this population have been reported.