Trichohepatoenteric syndrome is a condition that affects the hair (tricho-), liver (hepato-), and intestines (enteric), as well as other tissues and organs in the body. This condition is also known as syndromic diarrhea because chronic, difficult-to-treat diarrhea is one of its major features. Within the first few weeks of life, affected infants develop watery diarrhea that occurs multiple times per day. Even with nutritional support through intravenous feedings (parenteral nutrition), many of these children experience failure to thrive, which means they do not gain weight or grow at the expected rate. Most children with trichohepatoenteric syndrome are small at birth, and they remain shorter than their peers throughout life.
Abnormal hair is another feature of trichohepatoenteric syndrome. Hair in affected individuals is described as wooly, brittle, patchy, and easily pulled out. Under a microscope, some strands of hair can be seen to vary in diameter, with thicker and thinner spots. This feature is known as trichorrhexis nodosa.
Other signs and symptoms of trichohepatoenteric syndrome can include liver disease; skin abnormalities; and distinctive facial features, including a wide forehead, a broad base of the nose, and widely spaced eyes. Overall, the facial features are described as "coarse." Most affected individuals also experience immune system abnormalities that can make them prone to developing infections. Less commonly, trichohepatoenteric syndrome is associated with heart (cardiac) abnormalities. Mild intellectual disability has been reported in at least half of all children with the condition.
Trichohepatoenteric syndrome is often life-threatening in childhood, particularly in children who develop liver disease or severe infections.
Causes
Trichohepatoenteric syndrome can be caused by mutations in the TTC37 or SKIV2L gene. These genes provide instructions for making proteins whose functions have not been confirmed. Researchers speculate that they work together with other proteins within cells to help recognize and break down excess or abnormal messenger RNA (mRNA) molecules. mRNA is a chemical cousin of DNA that serves as the genetic blueprint for protein production. Studies suggest that getting rid of excess and abnormal mRNA is important for cell growth.
Mutations in the TTC37 or SKIV2L gene likely eliminate the function of their respective proteins, which is hypothesized to impair the breakdown of unneeded mRNA. However, it is unknown how these changes could lead to chronic diarrhea and the other features of trichohepatoenteric syndrome.
Summary
Trichohepatoenteric syndrome is a condition that affects the hair, liver, and intestines. The condition is characterized by chronic diarrhea that begins during the first six months after birth. Continued diarrhea can lead to an inability to gain weight (failure to thrive). Trichohepatoenteric syndrome also causes liver disease such as cirrhosis (chronic liver damage) or hepatomegaly (swollen liver). Affected individuals may have wooly or patchy hair. Tirchohepatoenteric syndrome is caused by mutations in TTC37or SKIV2L and is inherited in an autosomal recessive manner. The condition can be diagnosed by clinical examination and confirmed by genetic testing.Treatment options include nutrition through an IV (parenteral nutrition).
Symptoms
Trichohepatoenteric syndrome is named after the three main body systems that it affects: hair (tricho), liver (hepato), and intestines (enteric). The hair of people who have trichohepatoenteric syndrome may be wooly, patchy, or brittle. The hair may easily fall out due to each strand of hair having many thickened points surrounded by weak points (trichorrhexis nodosa). Trichohepatoenteric syndrome is also characterized by liver disease such as cirrhosis (chronic liver damage) or hepatomegaly (swollen liver). The intestinal problems associated with the condition are most characteristic of the disease. These problems include chronic diarrhea beginning in the first 6 months of life.
Other symptoms associated with trichohepatoenteric syndrome include characteristic facial features such as widely spaced eyes, a broad nose, and a wide forehead. People with trichohepatoenteric syndrome may also have a weakened immune system that makes it more difficult to fight infection. Some people may have skin abnormalities such as lightly-colored spots (café-au-lait macules), dry skin (xerosis), or skin that has a rubbery texture. Less commonly, some people with trichohepatoenteric syndrome have been born with heart abnormalities. About half of people affected by trichohepatoenteric syndrome have intellectual disability.
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.
Inheritance
Trichohepatoenteric syndrome is inherited in an autosomal recessive manner.[3] This means that mutations in both copies of either gene are required for a person to have symptoms of trichohepatoenteric syndrome. People who only have one copy of a gene that is changed are known as carriers. Carriers do not have symptoms of trichohepatoenteric syndrome. Each child of two carriers has a:
- 25% chance of having trichohepatoenteric syndrome
- 50% chance of being a carrier like both parents
- 25% chance of being unaffected and not being a carrier
Diagnosis
Trichohepatoenteric syndrome is diagnosed after an examination by a doctor shows symptoms suggestive of the condition. The exam might include a physical examination as well as a biopsy of the small intestine to search for other causes of the chronic diarrhea. A small intestine biopsy of people who have trichohepatoenteric syndrome may show some degeneration (atrophy) of the villi of the small intestine.
After a clinical examination is found to be suggestive of trichohepatoenteric syndrome, a doctor may order genetic testing to confirm the diagnosis. Genetic testing would look for mutations in both copies of TTC37 or SKIV2L.
Treatment
Trichohepatoenteric syndrome is treated symptomatically, meaning it is focused on treating the symptoms of the disease. Treating the chronic diarrhea is often the biggest concern, as chronic diarrhea can prevent people with trichohepatoenteric syndrome from getting enough nutrients. In most cases, treatment requires nutrition through an intravenous line, or IV. This is also called parenteral nutrition. If the liver disease associated with trichohepatoenteric syndrome permanently damages the liver, a partial or complete liver transplant may be required.
It may also be necessary to treat the weakened immune system associated with trichohepatoenteric syndrome. People with the condition may need treatment such as immunoglobulin infusions to boost the immune system.
Related Diseases
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.
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