What Is Aminoaciduria?
Also known as amino acid disease, amino aciduria, when the nervous system is involved, usually only mild mental retardation of development, until 2 to 3 years after the onset of symptoms. Like other hereditary metabolic diseases, amino acid disease does not affect fetal uterine growth or delivery, and may be early without signs. Phenylketonuria, tyrosineemia, and Hartnup disease are three clinically important early childhood amino acid diseases and are typical diseases due to biochemical defects.
Basic Information
- nickname
- Amino acid disease
- English name
- aminoacidopathy
- Visiting department
- Department of Genetics and Metabolism, Pediatrics
- Multiple groups
- Offspring married to close relatives
- Common causes
- Autosomal recessive pathogenicity
- Common symptoms
- Mild psychomotor retardation
- Contagious
- no
Etiology of Amino Acid Metabolism
- Except for some cases, amino acid metabolic diseases are all autosomal recessive, which are more common in offspring who are married to close relatives.
Clinical manifestations of amino acid metabolic diseases
- At present, there are more than 100 genetic diseases caused by disorders of amino acid metabolism. With the advancement of biochemical detection technology, new discoveries will continue to increase. The main clinical features are normal appearance and activity at birth, progressive decline of intelligence after half a year or one year old, appropriate amino acid supplementation, dietary control vitamins and other comprehensive treatment of neurological symptoms can be improved in many cases.
- Hereditary tyrosineemia
- (1) Can be divided into 3 types. Each type behaves differently. About half of the children have mild to moderate intellectual decline, may have self-harm behavior and uncoordinated physical movements, and have prominent language defects. Type 1 year old or nearly 1 year old, due to corneal erosion, often causes tears, photophobia and eye redness, neovascularization and corneal turbidity, palmar and plantar keratosis, often accompanied by sweating and pain, is a crystalline case Inflammation caused by the deposition of amino acids, nodules are also the cause of corneal lesions.
- (2) Type may show liver failure such as hepatosplenomegaly or liver cirrhosis, ascites, and often die after one or several years of illness. Neonatal tyrosineemia can cause liver failure and death. Increased blood tyrosine and urine tyrosine are of diagnostic significance, and amino acids such as blood methionine (methionine) can also be increased.
- 2.Hartnup disease
- (1) The child is normal at birth, and symptoms appear in late infancy or early childhood. The characteristic clinical manifestation is the intermittent appearance of red scaly rashes that spread across the face, neck, hands, and feet, which are similar to pellagra lesions.
- (2) There may be growth retardation, episodic personality disorders such as emotional changes, inability to control temper, insanity, hallucinatory psychosis, episodic cerebellar ataxia (gait instability, intentional tremor, and dysphonia, etc. ), Occasionally muscle cramps, dizziness, nystagmus, diplopia and corneal erosion, ptosis and other signs.
- (3) Sunshine, emotions, stress reactions, and taking sulfa drugs can trigger the onset of symptoms, which last for about 2 weeks, followed by periods of varying duration. As the child matures, the frequency of seizures gradually decreases, and some children may remain with a mild and persistent intellectual decline.
Amino Acid Metabolism Test
- Laboratory inspection
- Hematuria is routine, and liver function and hematuria amino acid content are of diagnostic significance.
- (1) In children with hereditary tyrosinemia, the blood tyrosine content is increased, urinary tyrosine is also increased, and amino acids such as blood methionine (methionine) may also be increased.
- (2) Children with Hartnup disease have increased urine neutral amino acids and urine proline, hydroxyproline, and arginine levels are normal.
- 2. Auxiliary inspection
- (1) EEG examination.
- (2) Genetic testing and prenatal diagnosis.
- (3) X-ray, CT and MRI examinations.
- 3. Related inspections
- Urinary amino acid nitrogen, total hydroxyproline, amino acids, arginine, proline, tyrosine.
Diagnosis of Amino Acid Metabolism
- The diagnosis of liver failure is mainly based on the typical clinical manifestations of different types of amino acid metabolic diseases and laboratory tests. Genetic testing is of diagnostic and differential significance.
Differential diagnosis of amino acid metabolic disease
- It needs to be distinguished from mental retardation, seizures, tremor ataxia, hypertonic reflex, and liver dermatitis caused by other causes such as lipid deposition disease, perinatal disease, and nervous system damage.
Amino Acid Metabolism Treatment
- 1. Amino aciduria with no obvious clinical symptoms, no special treatment is needed.
- 2. Only symptomatic treatment, can not change the prognosis and those with abnormal amino acid metabolism, such as children with abnormal amino acid metabolism, convulsive seizures must be treated with antiepileptic drugs, but can not improve the abnormal amino acid metabolism.
- 3. Try dietary therapy to control abnormal amino acid metabolism, low protein diet, supplement semi-synthetic amino acid mixed milk without metabolic accumulation amino acids, maple syrup urine disease, hyperammonemia with urea metabolism disorder; limit amino acid intake, such as high Lysineemia and so on.
- 4. High-dose vitamin treatment can improve the symptoms of amino acid metabolism diseases. This group of patients suffers from metabolic abnormalities caused by lack of certain coenzymes. Vitamin supplementation can change the metabolic process, such as vitamin B 6 dependence. Treatment of convulsions in infants; large doses of vitamin B 1 for maple syrup urination, vitamin B 12 for homocysteineemia, etc. Supplement minerals and trace elements.
- 5. Hereditary tyrosinemia is mainly symptomatic treatment. Low tyrosine and low phenylalanine diet can restore growth and development to normal and improve symptoms quickly, but treatment must be started early.
- 6. Apply L-carnitine to all diseases that cause elevated coenzyme A esters in the mitochondria (care should be taken to identify long-chain fatty acid oxidation disorders).
Prognosis of amino acid metabolism disease
- The prognosis of different types of amino acid metabolic diseases is different, and most of them have a poor prognosis. Seizures and ataxia are caused by common biochemical abnormalities. Most children show reduced learning ability and have varying degrees of intellectual decline.
Amino Acid Metabolism Prevention
- The treatment of genetic diseases is difficult, and the curative effect is not satisfactory. Prevention is even more important. Preventive measures include the avoidance of close marriages, genetic counselling, carrier genetic testing and prenatal diagnosis and selective abortion to prevent the birth of children.