• Tyrosinemia Type 2

Disease at a Glance

Summary
Tyrosinemia type 2 is a genetic disorder in which individuals have elevated blood levels of the amino acid tyrosine, a building block of most proteins. This condition can affect the eyes, skin, and intellectual development. Symptoms of Tyrosinemia type 2 often begin in early childhood and include excessive tearing, abnormal sensitivity to light (photophobia), eye pain and redness, and painful skin lesions on the palms and soles (palmoplantar hyperkeratosis). About 50 percent of individuals with this condition have an intellectual disability. Tyrosinemia type 2 is caused by a deficiency of the enzyme tyrosine aminotransferase, one of the enzymes required for the multi-step process that breaks down tyrosine. This enzyme shortage is caused by genetic changes in the TAT gene. This condition is inherited in an autosomal recessive manner.
Estimated Number of People with this Disease
In the U.S. there may be between

1 to 300

What Information Does GARD Have For This Disease?

Many rare diseases have limited information. Currently GARD is able to provide the following information for this disease:

*Data may be currently unavailable to GARD at this time.
Categories
Neurological Disease;
Skin Disease;
Inherited Metabolic Disease
When do symptoms of this disease begin?
The most common ages for symptoms of a disease to begin is called age of onset. Age of onset can vary for different diseases and may be used by a doctor to determine the diagnosis. For some diseases, symptoms may begin in a single age range or several age ranges. For other diseases, symptoms may begin any time during a person's life.
Prenatal
Before Birth
Newborn Selected
Birth-4 weeks
Infant Selected
1-23 months
Child
2-11 years
Adolescent
12-18 years
Adult
19-65 years
Older Adult
65+ years
The common ages for symptoms to begin in this disease are shown above by the colored icon(s).
This information comes from Orphanet

Symptoms

These symptoms may be different from person to person. Some people may have more symptoms than others and symptoms can range from mild to severe. This list does not include every symptom.
This disease might cause these symptoms:
Skin System

16 Symptoms

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Tile View
List View

Skin System

The skin or integumentary system is made up of skin, hair, nails, sweat glands, and oil glands. Common symptoms of problems in the skin system include redness, swelling, burning, itching, rashes, and hives. Skin diseases are often diagnosed and treated by dermatologists. Other specialists may also be involved including rheumatologists, allergists, and infectious disease doctors.
Medical Term

Abnormality of the nail

Frequency: Occasional
Description

Abnormality of the nail.

Abnormality of the nail.

Synonym

Nail disease

Nail disease

16 Symptoms
This information comes from the Human Phenotype Ontology (HPO)

Causes

Genetic Disease

Tyrosinemia type 2 is a genetic disease, which means that it is caused by one or more genes not working correctly.

The following gene(s) are known to be associated with this disease: TAT

  • Questions:

Questions:

What is a gene?
Genes are part of our DNA, the basic genetic material found in each of our body's cells. Cells are the building blocks of all living things and specialized cells form our body's organs and tissues. DNA is found in the nucleus of a cell and, in humans, is packaged into 23 pairs of chromosomes with the help of special proteins. 

Each gene performs a different job in our cells. Some genes serve as the instructions to make proteins. Proteins are needed for the structure, function, and regulation of the body's cells, tissues, and organs. Some genes can turn other genes on or off. Others make RNA molecules that are involved in chemical reactions in the body.

Sources to Learn More: What is a gene? (MedlinePlus) ; What's a Gene? (NHGRI) ; What are proteins and what do they do? (MedlinePlus)Genes are part of our DNA, the basic genetic material found in each of our body's cells. Cells are the building blocks of all living things and specialized cells form our body's organs and tissues. DNA is found in the nucleus of a cell and, in humans, is packaged into 23 pairs of chromosomes with the help of special proteins. 

Each gene performs a different job in our cells. Some genes serve as the instructions to make proteins. Proteins are needed for the structure, function, and regulation of the body's cells, tissues, and organs. Some genes can turn other genes on or off. Others make RNA molecules that are involved in chemical reactions in the body.

Sources to Learn More: What is a gene? (MedlinePlus) ; What's a Gene? (NHGRI) ; What are proteins and what do they do? (MedlinePlus)
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Inheritance

All individuals inherit two copies of most genes. The number of copies of a gene that need to have a disease-causing variant affects the way a disease is inherited. This disease is inherited in the following pattern(s):

Questions:

Autosomal recessive inheritance
Autosomal means the gene is located on any chromosome except the X or Y chromosomes (sex chromosomes). Genes, like chromosomes, usually come in pairs. Recessive means that both copies of the responsible gene must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.

A person who has an autosomal recessive disease receives a gene with a pathogenic variant from each of their parents. Each parent is a carrier which means they have a pathogenic variant in only one copy of the gene. Carriers of an autosomal recessive disease usually do not have any symptoms of the disease. When two carriers of an autosomal recessive disease have children, there is a 25% (1 in 4) chance to have a child who has the disease.Autosomal means the gene is located on any chromosome except the X or Y chromosomes (sex chromosomes). Genes, like chromosomes, usually come in pairs. Recessive means that both copies of the responsible gene must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.

A person who has an autosomal recessive disease receives a gene with a pathogenic variant from each of their parents. Each parent is a carrier which means they have a pathogenic variant in only one copy of the gene. Carriers of an autosomal recessive disease usually do not have any symptoms of the disease. When two carriers of an autosomal recessive disease have children, there is a 25% (1 in 4) chance to have a child who has the disease.
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Next Steps

Talking with the Medical Team

Good communication between the patient, family, and medical team can lead to an accurate diagnosis. In addition, health care decisions can be made together which improves the patient’s well-being and quality of life.

Describing Symptoms

Describe details about the symptoms. Because there may be many different causes for a single symptom, it is best not to make a conclusion about the diagnosis. The detailed descriptions help the medical provider determine the correct diagnosis.

To help describe a symptom:

  • Use a smartphone or a notebook to record each symptom before the appointment
  • Describe each symptom by answering the following questions:
    • When did the symptom start?
    • How often does it happen?
    • Does anything make it better or worse?
  • Tell the medical team whether any symptoms affect daily activities

Preparing for the First Visit

Working with a medical team to find a diagnosis can be a long process that will require more than one appointment. Make better health decisions by being prepared for the first visit with each member of the medical team.

    Make informed decisions about health care: 
    • Prepare a list of questions and concerns before the appointment
    • List the most important questions first, not all questions may be answered in the first visit
    • Ask questions about symptoms, possible diagnoses, tests, and treatment options
    For future appointments:
    • Discuss what was not addressed at the last visit
    • Discuss changes in the quality of life for the patient, family, and caregivers
    • Discuss health goals and other issues in the patient’s and family’s life that may affect the health care decisions
    Take notes during the appointments to help remember what was discussed.

    Next: Diagnosis & Treatment

    Last Updated: Nov. 8, 2021