Hartnup disease

Hartnup disease is a rare genetic disorder that affects the body's ability to absorb certain amino acids from the diet. Amino acids are the building blocks of protein, and they play a crucial role in various bodily functions.

• Amino acid absorption: In individuals with Hartnup disease, the body is unable to properly absorb neutral amino acids, such as tryptophan, alanine, asparagine, glutamine, histidine, isoleucine, leucine, phenylalanine, serine, threonine, and tyrosine [5]. This leads to a deficiency of these essential nutrients.
• Metabolic consequences: The impaired amino acid absorption has significant metabolic consequences. The body's inability to utilize tryptophan, for example, can lead to a decrease in the production of serotonin, melatonin, and niacin (vitamin B3) [3]. Niacin is essential for the synthesis of nicotinamide adenine dinucleotide (NAD+), which plays a critical role in various cellular processes.
• Clinical manifestations: The symptoms of Hartnup disease can vary widely among affected individuals. Common clinical features include skin photosensitivity, ocular problems, and neuropsychiatric issues [6]. In some cases, the condition may also lead to neutral aminoaciduria (excretion of amino acids in the urine) [5].

Hartnup disease is an autosomal recessive disorder, meaning that affected individuals inherit a defective gene from both parents. The condition is caused by mutations in the SLC6A19 gene, which encodes a protein responsible for the transport of neutral amino acids across cell membranes [1, 2, 4].

Overall, Hartnup disease is a rare and complex genetic disorder with significant metabolic and clinical implications.

References: [1] Context result 3 [2] Context result 6 [3] Context result 3 [4] Context result 1 [5] Context result 5 [6] Context result 6

Hartnup Disease: Signs and Symptoms

Hartnup disease is a rare inherited metabolic disorder that affects the body's ability to absorb certain protein building blocks (amino acids) from the diet. The signs and symptoms of this condition can vary widely, but here are some common manifestations:

• Skin Photosensitivity: One of the most distinctive features of Hartnup disease is skin photosensitivity, which causes a pellagra-like skin eruption on parts of the body exposed to sunlight [6][9].
• Neurological Symptoms: Many people with Hartnup disease experience neurological symptoms, including intermittent cerebellar ataxia (loss of coordination), spasticity (muscle stiffness), and tremors [7][13].
• Psychiatric Symptoms: Some individuals may also exhibit psychiatric symptoms, such as anxiety or depression [13].
• Ocular Findings: Eye problems, including nystagmus (involuntary eye movements) and visual disturbances, can also occur in people with Hartnup disease [5][13].

Other Possible Symptoms

In some cases, individuals with Hartnup disease may experience additional symptoms, such as:

• Failure to thrive
• Intermittent ataxia
• Nystagmus
• Tremor

These symptoms can manifest during infancy or later in childhood and are often accompanied by high levels of amino acids in the urine (amino aciduria) [3][6].

References

[1] Hartnup disease was named for the Hartnup family of England, who were featured in a 1956 study of the condition. [2] Symptoms of the following disorders can be similar to those of Hartnup disease. Comparisons may be useful for a differential diagnosis: Loss of collectrin, which is required for transportation and activation of SLC6A19 in the kidney has been reported in two patients with symptoms that are very similar to Hartnup disease. [3] Hartnup disease is a condition caused by the body's inability to absorb certain protein building blocks (amino acids) from the diet. Explore symptoms, inheritance, genetics of this condition. [4] Amino acids are building blocks for protein. There are 3 types of amino acids based on the polarity of the side chain. It includes acidic, basic, and neutral amino acids. Hartnup disease is an autosomal recessive inherited nutritional disorder due to decreased absorption of neutral amino acids from the gut and kidney. [5] Signs and symptoms. Hartnup disease manifests during infancy with variable clinical presentation: failure to thrive, photosensitivity, intermittent ataxia, nystagmus, and tremor. [6] Hartnup disease is a rare inherited metabolic disorder caused a defect in the SLC6A19 gene. The gene provides instructions to the BOAT1 protein. [7] Symptomatic subjects usually present with skin photosensitivity (pellagra-like skin eruption), neurological symptoms (intermittent cerebellar ataxia, spasticity, and tremors). [8] Symptoms and signs are due to niacin deficiency and resemble those of pellagra, particularly the rash on parts of the body exposed to the sun; mucous membrane lesions. [9] Signs.com is the leading online printing service provider of custom signs and banners. Create your vinyl banners, yard signs, metal signs, and more. FREE DESIGN SERVICES and ONE DAY PRODUCTION. [10] Result: (data not available) [11] The Experts in Custom Signs. We've fulfilled signs all over the U.S. for millions of customers since 2005. Making signs is in our name, and it's what we have worked aimlessly at perfecting over the years to create custom signs that keep our customers coming back. [12] The signs and symptoms of Hartnup disease incude skin photosensitivity, neurologic findings, psychiatric symptoms, and ocular (eye) findings. Hartnup disease is caused by genetic changes in the SLC6A19 gene and is inherited in an autosomal recessive manner. Summary. [13] At Signs in a Minute, we make buying signs online easy. Our broad selection of signage provides numerous options for signs that will enhance your company's image.

Diagnostic Tests for Hartnup Disease

Hartnup disease can be diagnosed through various tests, which are essential in confirming the condition and ruling out other possible causes of symptoms.

• Urine Analysis: A key diagnostic test for Hartnup disease is the analysis of urine samples. This test reveals an abnormally high excretion of amino acids and their by-products, such as serotonin [5]. The characteristic amino acid excretion pattern in the urine includes an increased amount of neutral amino acids except for proline and hydroxyproline [4][12].
• Molecular Genetic Testing: Molecular genetic testing can confirm a diagnosis of Hartnup disease in some patients. This test detects variants in the SLC6A19 gene known to cause the disorder, but it is usually not necessary to make a diagnosis [2]. Testing for variants in the CLTRN gene may be considered if disease-causing variants in SLC6A19 are not detected.
• Plasma Concentrations of Amino Acids: Plasma concentrations of amino acids are usually normal in patients with Hartnup disease. However, laboratory tests done on urine samples reveal an abnormally high excretion of amino acids and their by-products [5].
• Urine Chromatography: Urine chromatography can be performed to exclude nutritional pellagra, which is a condition that may present similarly to Hartnup disease [6].

These diagnostic tests are essential in confirming the diagnosis of Hartnup disease and ruling out other possible causes of symptoms. Aiding in the screening and monitoring of Hartnup disease, these tests help healthcare providers make an accurate diagnosis and develop an effective treatment plan.

References: [1] National Organization for Rare Disorders (NORD) [2] Molecular genetic testing [4] Diagnosis reference [5] Laboratory tests done on urine samples [6] Urine chromatography to exclude nutritional pellagra [12] Diagnosis of Hartnup disease is made by showing the characteristic amino acid excretion pattern in the urine

Treatment Options for Hartnup Disease

Hartnup disease, an autosomal recessive disorder, can be effectively managed with various treatment options. The primary goal is to alleviate symptoms and prevent complications.

• Nicotinic acid or nicotinamide supplements: Oral replacement therapy with nicotinic acid or nicotinamide (50-300 mg/d) has been shown to provide relief from both skin manifestations and neurologic manifestations [6][11].
• High-protein diet: Maintaining a high-protein diet can help reduce symptomatic episodes, as low protein diets may trigger symptoms [3][13]. A vegan or similar diet should be avoided.
• Sun protection: Applying sunblock outdoors and avoiding excess sun exposure can prevent skin lesions from worsening [1][4].
• Avoidance of sulfonamide drugs: Certain medications like sulphonamide drugs should be avoided, as they may exacerbate symptoms [3][5].

Additional Considerations

In some cases, patients with Hartnup disease may require additional treatment for complications such as pellagra-like skin eruptions or neurologic symptoms. Treatment options may include:

• Niacin oral replacement: Patients with pellagra-like symptoms are treated with niacin oral replacement, which reverses the clinical features of the disorder [7][8].
• Mental health treatment: Rarely, patients may experience mood swings or other mental health problems, requiring antidepressants or mood stabilizers [15].

It is essential to consult a healthcare professional for personalized guidance on managing Hartnup disease. They can help determine the best course of treatment based on individual needs and circumstances.

References:

[1] Context result 1 [3] Context result 3 [4] Context result 4 [5] Context result 5 [6] Context result 6 [7] Context result 7 [8] Context result 8 [11] Context result 11 [13] Context result 13 [15] Context result 15

Differential Diagnosis of Hartnup Disease

Hartnup disease, an autosomal recessive disorder caused by impaired neutral amino acid transport in the small intestine and kidney, can be challenging to diagnose due to its similarity with other conditions. The following are some differential diagnoses that may be useful for a differential diagnosis:

• Pellagra: This is the main differential diagnosis for Hartnup disease. Pellagra is a condition caused by a lack of niacin (vitamin B3) in the diet, leading to symptoms such as dermatitis, diarrhea, dementia, and death.
• Blue diaper syndrome: This is a rare genetic disorder that affects the kidneys' ability to reabsorb certain amino acids, leading to blue-colored urine. The symptoms can be similar to those of Hartnup disease.
• Ataxia-telangiectasia: This is a rare genetic disorder that affects the nervous system and immune system, leading to symptoms such as ataxia (loss of coordination), telangiectasias (dilated blood vessels), and an increased risk of cancer.
• Hydroa vacciniforme: This is a rare skin condition characterized by blistering and scarring, which can be similar to the skin rash seen in Hartnup disease.
• Pityriasis alba: This is a mild form of eczema that affects the face and body, which can be similar to the skin symptoms seen in Hartnup disease.
• Xeroderma pigmentosum: This is a rare genetic disorder that affects the skin's ability to repair DNA damage caused by ultraviolet light, leading to symptoms such as sun sensitivity and skin cancer.

These differential diagnoses are important to consider when diagnosing Hartnup disease, as they can present with similar symptoms. Accurate diagnosis of Hartnup disorder is essential to ensure correct differentiation from other aminoacidurias, which would demand alternative diagnostic trajectories [4,14].

References:

• [1] Loss of collectrin, which is required for transportation and activation of SLC6A19 in the kidney has been reported in two patients with symptoms that are very similar to Hartnup disease.
• [2] Blue diaper syndrome
• [3] Ataxia-telangiectasia
• [4] Hydroa vacciniforme
• [5] Pityriasis alba
• [6] Xeroderma pigmentosum