About hartnup disease

What is hartnup disease?

Hartnup disease is a rare metabolic disorder inherited as an autosomal recessive trait. It involves an inborn error of amino acid metabolism as well as niacin deficiency. Factors that may precipitate acute attacks of this disorder may include poor nutrition, exposure to sunlight, sulphonamide medications and/or psychological stress. Hartnup disease may be marked by skin problems, coordination impairment, vision problems, mild mental retardation, gastrointestinal problems, and central nervous system abnormalities. Frequency of attacks usually diminishes with age.

What are the symptoms for hartnup disease?

Delusions symptom was found in the hartnup disease condition

The symptoms of Hartnup disease vary greatly from one person to another. The majority of affected individuals do not have any apparent symptoms (asymptomatic). When symptoms do develop, they most often occur between the ages of 3-9. In rare instances, symptoms first appear in adulthood.

The most common symptom are red, scaly light-sensitive (photosensitive) rashes on the face, arms, extremities, and other exposed areas of skin.

A wide variety of neurological abnormalities can occur including sudden episodes of impaired muscle coordination (ataxia), an unsteady walk (gait), impaired articulation of speech (dysarthria), occasional tremors of the hands and tongue, and spasticity, a condition marked by increased muscle tone and stiffness of the muscles, particularly those of the legs.

There have been reports of delayed cognitive development and, in rare instances, mild intellectual disability in some children. It is, however, unclear whether these symptoms are related to Hartnup disorder or incidentally occurred in the same individual and were therefore attributed to Hartnup disorder. Similarly, Seizures, fainting, trembling, lack of muscle tone (hypotonia), Headaches, Dizziness and/or vertigo, and delays in motor development have been observed but may be unrelated. Some affected individuals may experience psychiatric abnormalities including emotional instability such as rapid mood changes, depression, Confusion, anxiety, delusions, and/or hallucinations.

Some children experience growth delays and may be shorter than would be expected based upon age and gender (short stature). In some instances, the eyes may be affected and individuals may experience double vision (diplopia), involuntary rhythmic movements of the eyes (nystagmus), and droopy upper eyelids (ptosis).

Diarrhea may precede or follow an episode of this disorder. Some adults with Hartnup disease have been reported whose initial symptom was the onset of Seizures during adulthood. Heartburn has been reported in adults with the disorder.

What are the causes for hartnup disease?

Hartnup disease is caused by alterations (mutations) in the SLC6A19 gene. Genes provide instructions for creating proteins that play a critical role in many functions of the body. When a mutation of a gene occurs, the protein product may be faulty, inefficient, or absent. Depending upon the functions of the particular protein, this can affect many organ systems of the body.

These alterations are inherited in an autosomal recessive manner. Most genetic diseases are determined by the status of the two copies of a gene, one received from the father and one from the mother. Recessive genetic disorders occur when an individual inherits two copies of an abnormal gene for the same trait, one from each parent. If an individual inherits one normal gene and one gene for the disease, the person will be a carrier for the disease but usually will not show symptoms. The risk for two carrier parents to both pass the altered gene and have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier like the parents is 50% with each pregnancy. The chance for a child to receive normal genes from both parents is 25%. The risk is the same for males and females.

The SLC6A19 gene produces a protein known as an amino acid transporter, which serves to assist the movement (or transport) of specific amino acids within the body. This protein is especially active within the kidneys and the intestines, although these organs are otherwise unaffected and function normally. The amino acids affected include tryptophan, alanine, asparagine, glutamine, histidine, isoleucine, leucine, phenylalanine, serine, threonine, tyrosine, and valine.

Amino acids are the chemical building blocks of proteins and are essential for proper growth and development. Because of the underlying genetic defect in Hartnup disease, the intestines cannot properly absorb amino acids and the kidney cannot properly reabsorb them, leading to excessive amounts of amino acids being lost through the passage of urine. This leaves the body with reduced amounts of amino acids to serve as the building blocks of proteins. Deficiency of the amino acid tryptophan is believed to account for the symptoms associated with Hartnup disease. Tryptophan is essential for the creation (synthesis) of nicotinamide, which is also supplemented through nutrition as a vitamin (also known as vitamin B3).

This deficiency is most problematic during times of illness or stress. Precipitating factors that may cause acute episodes of Hartnup disease may include a period of poor nutrition, fever, exposure to sunlight, sulphonamide medications, illness, and/or psychological stress.

What are the treatments for hartnup disease?

Individuals with Hartnup disease who do not develop symptoms will usually not require any treatment. Low protein diets (vegan or similar) may trigger symptomatic episodes, which can be reduced or avoided by maintaining good nutrition including a high protein diet, avoiding excess exposure the sun, and avoiding certain drugs such as sulphonamide drugs. Supplementing the diet with nicotinamide or niacin is also of benefit in preventing Hartnup disease episodes.

In some instances, during a symptomatic episode, treatment with nicotinamide may be recommended.

According to the medical literature, at least one individual showed an improvement of symptoms after treatment with the compound L-tryptophan ethyl ester, which restored tryptophan levels in both the serum and cerebrospinal fluid.

Other treatment is symptomatic and supportive. Genetic counseling may be helpful for affected families.

What are the risk factors for hartnup disease?

Hartnup disease is also referred to as Hartnup disorder, an uncommon genetic condition involving an inborn mistake in amino acid metabolism. It makes it challenging for your kidneys to reabsorb specific amino acids from your intestine. Amino acids are necessary for proper growth and development since they are the chemical building blocks of proteins. Many amino acids are lost through the urine tract when someone has hartnup disease because the intestines cannot properly absorb them.

High quantities of specific amino acids are found in the urine of those with Hartnup disorder (aminoaciduria). It is typically the primary indication of the disease in those affected. Hartnup disease patients occasionally experience additional symptoms, such as skin rashes, trouble coordinating their movements, and psychological symptoms, including depression or psychosis.

The risk factors for hartnup disease

  • Hartnup disease can create issues like weakness and appetite loss.
  • Additionally, the patient may suffer from anxiety, emotional instability, sleeplessness, diarrhea, or constipation.
  • It makes the skin feel burning or stinging, specifically after exposure to the sun.
  • The patient can experience a painful throat issue.
  • The disease, which can affect the skin to be rough, scaly, and reddish-brown, typically develops from nutritional deficiencies.

Skin rash,Anxiety,Rapid mood swings,Delusions,Hallucinations,Intention tremor,Speech difficulties
Protein and niacin in the diet,Supplements of nicotinamide or niacin, antibiotics that contain sulfonamides,Avoiding sun exposure etc
Short stature,Delusions,Anxiety,Speech difficulties,Rapid mood swings,Hallucinations, Intention tremor,Sensitivity to light,Speech difficulties,Abnormalities in muscle tone,Skin rash and so on

Is there a cure/medications for hartnup disease?

Hartnup disease is another name for Hartnup disease. The metabolic condition is inherited. Your body finds it challenging to reabsorb some amino acids from your kidneys after your body has absorbed them from your intestine. Your body needs amino acids as fundamental building blocks to produce protein.

  • The Hartnup family of England, who was highlighted in a 1956 investigation of the ailment, gave rise to the moniker Hartnup sickness.
  • It was discovered that four out of eight family members had abnormally high levels of amino acids in their urine.
  • They also experienced a skin rash and ataxia, which is the inability of voluntary muscular movements to coordinate.
  • These are the hallmarks of Hartnup illness, which often has an impact on the skin and brain.
  • People with Hartnup illness can typically lead normal lives.
  • Rarely does the condition develop complications.
  • But it's also possible that this disorder will cause changes in your skin's color, difficulty coordinating your motions, or psychiatric issues.
  • You might occasionally acquire neurological disorders.
  • Although some nervous system disorders can be fatal, your doctor can usually successfully treat them.
  • Consult your doctor for management techniques to control your condition and reduce the likelihood of problems.

Skin rash,Anxiety,Rapid mood swings,Delusions,Hallucinations,Intention tremor,Speech difficulties
Protein and niacin in the diet,Supplements of nicotinamide or niacin, antibiotics that contain sulfonamides,Avoiding sun exposure etc
Short stature,Delusions,Anxiety,Speech difficulties,Rapid mood swings,Hallucinations, Intention tremor,Sensitivity to light,Speech difficulties,Abnormalities in muscle tone,Skin rash and so on

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