Showing posts with label Citrullinemia. Show all posts
Showing posts with label Citrullinemia. Show all posts

Saturday

Citrullinemia


Disease etiology principle

Tingting told parents this is a flowchart of urea metabolism and circulation, this figure is to tell us when the body is then broken down into amino acids intake of protein for human use, and then metabolized through the liver will convert toxic ammonia that is urea into non-toxic substances, and by urine. In the urea cycle, must by many enzymes to help break down the body's functioning, such as: NAGS (N-acetylglutamate synthetase; N-acetyl glutamate synthesis transaminase), CPS (Carbamoyl phosphate synthetase; A unitary unitary first phosphate synthetase each), AS (Argininosuccinate synthetase; spermine acid synthase), AL (Argininosuccinate lyase; spermine amber hydrolysis transaminase), Arginase (Arg), OTC (Ornithine transcarbamylase; ornithine amino acyl transfer A transaminase deficiency) of several enzyme transaminase. Occurs when each part of the enzyme deficiency, can not successfully make the ammonia metabolism disease, and will reflect the upstream detection index is high, the low value of the downstream testing situations. By Tingting speaking on our blood amino acids from her LC MS / MS inspection reports that Glutamine (glutamine) 2460umol / L (normal is less than one year old 31-560umol / L) and Citrulline (citrulline) 1430umol / L (normal is less than one year old 11-27umol / L) and many other indicators are high in Arginine (Arg) 1.16umol / L (normal is less than one year old 5-73umol / L) index is low. Therefore, we will be highly suspected Tingting argininosuccinate synthase (succinate spermine synthase) exception occurs citrulline concentrations continue to rise, leading to high blood ammonia and other abnormal clinical signs, these are likely to belong to gene mutation. Citrulline-related diseases, including metabolic disorders; citrullinemia type I (citrullinemia type I), citrullinemia type II (citrullinemia type II), and spermine enzyme deficiency succinate (Argininosuccinic aciduria ), etc.




The incidence of disease and genetic patterns
Citrullinemia (Citrullinemia) in Taiwan occur in approximately 1/14, 000, are of rare diseases subsequently. Citrullinemia (Citrullinemia) mode of inheritance is autosomal recessive disease, which means that parents will each with a mutated gene, and the clinical symptoms will not have symptoms, it is called with the result of those. The human body has 22 pairs of autosomes and one pair of sex chromosomes, after mitosis embryonic development process, chromosomes from the father and the mother would choose each half to form 22 pairs of chromosomes of the fetus. If the father and mother happened with the mutated gene is passed to the next generation, the formation of autosomal recessive mode, you will be sick. In other words, regardless of gender, Tingting's parents at each tire will be 1/4 chance of suffering from birth citrullinemia (Citrullinemia) this disease.

Characterization of clinical disease
Citrullinemia type I (Citrullinemia Type I) citrullinemia type II (Citrullinemia Type II)Main reasons: succinate spermine synthase (Argininosuccinate synthetase; ASS) dysfunction caused. Citrin vivo protein (lemon prime carrier protein) functional deficiency caused.Time of onset of the great difference in time of onset patients, after 24 hours from birth to early childhood before onset. Can be divided into early onset: neonatal onset (Neonatal Hepatitis Associated with Choletasis; NICCD), and late onset: adult onset (Adult-onset Type II Citrullinemia).If the clinical characterization of onset in the neonatal period, the early symptoms are generally poor feeding, vomiting, drowsiness, restlessness, shortness of breath, rapid changes in conditions or serious neurological problems with the autonomic nervous system. Without proper treatment, most will die or produce complications.If the childhood disease, the symptoms will be relatively not so serious, but it may have been obvious brain lesions.If you were born in the neonatal onset of about one to five-month period, appears cholestatic jaundice, liver functionDiagnostic methods in common: blood test for ammonia values ​​citrulline values, and other related amino acids and liver function testsGene seat: 9q34 7q21.3 of SLC25A13 gene mutationsOther liver cells or skin fibroblasts for spermine acid synthase activity checks.Treatment: 1. Acute increases when ammonia is necessary to remove the ammonia hemodialysis. Hyperammonemia time if more than 24 hours, will be on neonatal brain damage.(2) the use of special drugs (phenylacetate) help the body discharge of ammonia.1 neonatal onset patients, fat-soluble vitamin supplementation, and the use of lactose-free and contains medium-chain fatty (middle-chaintriglycerides; MCT) special milk powder, an average of 12 months old when good treatment can attainable effectiveness; few cases even without specific treatment, the symptoms can be gradually improved.2 adult onset patients, if after liver transplantation therapy can be effective in preventing high blood ammonia problems, and correct metabolic abnormalities issue.3 Oral arginine will reduce the accumulation of ammonia, and reduce heat and increase protein intake, you can improve high blood triglycerides (Hypertriglyceridemia).Diet therapy should adopt high-calorie, low-protein diet. Should adopt high-fat, high-protein and low-carbohydrate diet.Precautions to track return visits regularly, monitor growth and development, ammonia and related values ​​essential amino acids to maintain normal physiological needs, usually should pay attention to the impending hyperammonemia characterization; include: altered consciousness, headache, bad (lethargy), drowsiness (nausea), vomiting, poor appetite, poor feeding (refusal to feed) and ankle cramps (ankle clonus) and so on.1 to avoid excessive intake of protein, and infection problems.(2) when the disease is more severe, a liver transplant will be of great help for the disease.1. Adopt low protein / high calorie diet, protein function citrin deficiency type II citrullinemia harmful.(2) high-calorie diet, will increase citrullinemia patients with type II NADH generation, interfere with normal urea synthesis and stimulate citrate-malate delivery, and lead to high blood ammonia, and fatty liver, high triglycerides the occurrence of disease.3 When citrullinemia type II patients with acute symptoms and cerebral edema (brain edema) problems should avoid injection of glycerol and sugars (glycerol and fructose), so as to avoid increasing the generation of NADH, resulting in abnormal liver function and produce toxic substances.4 reduces fasting or fasting, avoid high blood ammonia problems.5 Avoid alcohol or alcoholic foods, because alcohol dehydrogenase alcohol can irritate (alcohol dehydrogenase; ADH) activity in the liver and promote increased synthesis of NADH to produce harmful substances.




Outpatient cases basic information

Basic information:Name: Tingting Gender: Female Age: 3 days
Tingting was born on the third day of female infants, due to a sudden emergency pumping spasm and then was transferred to a coma NICU. In the neonatal intensive care unit for treatment and medical treatment process, Tingting body found in ammonia (ammonia) index is high is cause sudden coma reasons, but Tingting why hyperammonemia symptoms of it? Went against metabolic diseases Looking in the urine organic acid detection and tandem mass spectrometry newborn screening are confirmed citrullinemia (Citrullinemia). Tingting Why get this disease through genetic testing that each parent with a gene mutation point C.380G> A, p.R127Q, Heterozygous Tingting who presented with mutations point C.380G> A , p.R127Q, Homozygous is the same. Thus, for the first type Tingting confirmed citrullinemia (Citrullinemia) and belong to one of the rare disease hereditary disease. Currently Tingting home successfully and no recurrence of hyperammonemia condition, weight 5.2kg, eating some food orally for every three hours 120CC, occasionally overflows, no spitting, no oliguria, slightly loose stools, etc. . Tingting's parents want to know more about "citrullinemia (Citrullinemia)" relevant information and follow-up care of the problem.
Family Trees

(To respect the privacy of cases, case names begin with a pseudonym processing, spectrum and content of the story of his family has been changed)


Genetic outpatient consultation process
A nutritional care sections:Tingting has been identified as citrullinemia type I patients, is now one month old. Fortunately Tingting after the first attack, there is no significant complications occurred, and no recurrence of hyperammonemia phenomenon. Tingting Tingting's parents already know is necessary to use special nutritional formula, milk Tingting staple part from the high-calorie, low-protein diet adjustments. In nutrition, you must calculate and discuss in detail through nutritionist, so Tingting growth process in a lifetime, to be able to have enough calories and protein metabolism process does not cause a burden. Future growth process, parents must learn how to record and diet, how to cook food, how to teach Xiao Ru food choices, how to observe and avoid intake of other foods Tingting privately, and how schools (kindergarten or elementary school) in the nutrition section do adjustments, and even some parents to prepare their own. We all know these processes Tingting parents is hard, but it is also one of the best ways for Tingting.
Two. Disease drug therapy sections:Another object is to provide drugs eliminate waste nitrogen way. Common drugs (1) Sodium benzoate (Ucephan): mainly associated with glycine (glycine) to form hippuric acid (hippurate), through the urine. This type of drug has intravenous and oral dosage forms taken 3-4 times a day, while the side effects are nausea, vomiting, tinnitus, visual disturbances. (2) Sodium phenylbutyrate (Buphenyl): mainly in the liver may be oxidized to phenylacetate, and then combined with glutamine to form phenylacetylglutamine final product by the urine. (3) Arginine (Arginine): arginine by the enzyme (arginase) the role of the arginine into urea and ornithine (ornithine). These drugs must be long-term outpatient follow with doctors and nutritionists with through regular biochemical tests, recording height and weight development, adjusted to fit Tingting situation.
Three. Liver transplant:The purpose is to help liver transplant originally Tingting protein metabolism in the liver, the situation has improved and is therefore indeed can change Tingting lifestyle, do not need to rely on diet control. But there are certain things that must be thinking, such as: (a) who fits the liver transplant Tingting, mostly pro-lineal five other blood diseases within and without (B type hepatitis disease or carriers, AIDS etc.), blood and other parts are in compliance with those. (2) How much needed liver transplants, most have adopted adults and only 1/3 of the can. (3) what is to be done prior to transplantation should be assessed with the experts appropriate time, and Tingting recommended that at least 10 kg body weight or more, between the donor and recipient is low compared to exclusion. (4) the time of transplantation, donor and recipient by key required hospitalization, blood drive with the computer off when physical conditions such as evaluation, recipients must first chemotherapy will minimize its own white blood cells of the state has been favorable transplant success rate . (5) after transplantation, the donor must trace back to the clinic for some time, recipients must be hospitalized longer period of observation and must start taking anti-rejection drugs for life, to avoid being infected with the situation with regular visits tracked. (6) When will I know there is rejection reactions occur, such as: fever, infection, complications such as biliary obstruction, physical condition because each different severity of sequelae, some even death. Therefore, Tingting Tingting's parents to look at the situation now is very stable and not more than 10 kg body weight, do not need to rush to some liver transplant, when Tingting encounter recurrent episodes of hyperammonemia or no longer such as by the oral intake deteriorated conditions, it is the time when you need to perform a liver transplant. So, Tingting's parents, you can consider this treatment and can do this partly for the previous preparation, looking for a suitable donor, do preventive preparations.
Four. Development and tracking components:Tingting diseases due to the relationship, let her grow by some obstacles, but compared with the same age children seem smaller, shorter, but if the parents are in accordance with the instructions given nutritionist care is basically Xiao Ru will not did not grow. Therefore, they are better than expected with Tingting is growing can be.Tingting intelligence in part is less affected, unless the emergence of long-term hyperammonemia caused severe brain injury sequelae. Therefore, parents in infancy or Tingting, you must learn how to observe the symptoms of high blood ammonia and know how to deal with an emergency to a medical institution, and remind Tingting diseases and medical staff to be temporarily fasting glucose given intravenously given Sodium benzoate, Sodium phenylbutyrate, L-arginine and other drugs, and even reducing intracranial pressure dialysis and drug use and so on.Tingting patient examination takes about a month back and observe the control situation, to see if you need help train other relevant departments, such as early intervention for developmental assessment.

Monday

Citrullinemia

Melon Hyperlipemia acid urea cycle metabolic abnormalities are one of these diseases are caused because of the lack of enzymes. Urea cycle, melon acid (citrulline) are Carbamoyl phosphate and Ornithine (Ornithine) after a product. Under normal circumstances, melon acid succinate further by spermidine synthase (argininosuccinate synthetase) and aspartic acid (asparate) combine to produce succinate spermine (argininosucinate, AS). Each molecule of urea contains two nitrogen atoms (N), one from ammonia (NH3), and one from aspartic acid (asparate). argininosuccinate synthetase resulted in the lack of melon acid accumulation, known as the melon acid type hyperlipidemia.

Most nitrogen from protein and amino acid metabolism, and urea nitrogen cycle is the body to remove the main path. Mainly in the liver urea cycle performance, the response has mostly mitochondrial, have a part in the cytoplasm are inside, be able to put a toxic substance (ammonia), converted into a more non-toxic substances (urea), then by the urine Medium discharged. Mitochondria may affect the metabolism of urea generation, lead to high blood ammonia disease. Overall speaking, urea cycle by N-acetyl glutamic acid (N-acetylglutamate, NAG) control the speed of synthesis, the enzyme catalyst (NAG) open the ammonia into the urea cycle.

Argininosuccinate synthetase general will be transported to the brain, kidney, skin and fibrous tissue the role of mother cells, so melon acid can also be other than by metabolism in the liver. Melon acid in patients with hyperlipidemia a genetic defect will be manifested in these organizations. Urea cycle, melon aspartic acid and lysine combination, the second waste nitrogen molecules to enter the circle; when the urea cycle of damage, resulting in the ability of ammonia excretion decreased by 50%, have high blood ammonia in patients with disease situation .

Genetic model

Japan had cases in the adults find some kind of specific, previously undetected and treatment of hyperlipidemia melon acid, but also has patients after 48-year-old was found. Since some patients have developmental delay period, but most patients are only the incidence of symptoms. Melon acid so the incidence of hyperlipidemia in patients with age and ornithine amino-acyl transfer A deficiency (Orinithine transcarbamylase deficiency) are as unpredictable. Mortality and morbidity rates are high.

Melon acid hyperlipidemia for autosomal recessive genetic disease, both parents are carriers of the recessive (carrier: the Parent with a defective gene, but no clinical symptoms), the patient must at the same time with two a defect gene (from the Parent a) before the incidence. As long as both parents are carriers, 25% chance of giving birth to children, has 50% chance of a child for the carriers. The disease has no gender-neutral probability.

Melon acid Hyperlipemia ninth pathogenicity gene located on chromosome long arm (9q34). Have at least 20 point mutations have been discovered. Age at onset urea cycle and other metabolic disorders the same as the incidence of indeterminate age, the most common age of onset of the neonatal period. The neonatal period did not grow up the children with treatment, may have the consequences of mental retardation.

Symptoms

Symptoms of high blood ammonia, along with lack of appetite, vomiting, fatigue, irritability, cramps; cerebral edema and coma if not treated in time may cause death. Incidence of the neonatal period is usually, but symptoms may be a few days or weeks before unnoticed. The severity of clinical symptoms and rely on their individual circumstances vary. In general there may be high ammonia conditions, the growth of the poor. If cerebral edema may result in papilledema (papilledema), intracranial pressure will also increase. Lung area, there may be shortness of breath or too strong case may be will be late apnea or failure. Moderate hepatomegaly may also happen phenomenon. Neural connection, there may be poor coordination disorder power sports (dysdiadochokinesia), the tension is too low or too strong, ataxia, tremor, cramps, drowsiness. Complications mainly neuropathy, including mental retardation, acute high blood ammonia coma, or even death.

Diagnosis

The symptoms of patients, first and foremost is the measurement of blood ammonia (NH3) concentrations, useful for diagnosis on biochemical values. Another is a measure of blood amino acid concentration, incidence of the patients, their blood will be obvious melon acid increased to 1000-5000  M (normal 10-20  M). Urinary concentrations of amino acids, organic acid concentration and urinary orotic acid (orotic acid) can also be used as the reference value. Patients with urine orotic acid concentrations rise.
Measurement of skin cells of fibrous tissue Argininosuccinate synthetase, could provide specific biochemical diagnosis.

Prenatal diagnosis

Do amniocentesis (amniocytes) or chorionic villi to do molecular diagnostics.

Treatment

The goal of treatment is to correct the biochemical imbalance and to ensure that nutritional requirements. Under the situation of high ammonia immediately restricted diet of protein, strengthen the non-protein energy sources, to avoid compensatory disorders. Serious, it is possible to quickly remove ammonia hemodialysis.

Low-protein diet
According to patient's age and disease severity of the decision of protein intake, each patient's needs are quite different. Six months ago, because it is fast-growing period, patients may need more protein or 1.5g/kg/day; preschool period, protein intake is usually reduced to 1.2 ~ 1.5g/kg/day; school-age children may be to fell 1 g / kg / day. After puberty, the amount of protein may be less than 0.5g/kg/day.

Drug
Drugs to provide an alternative way to rule out the possibility of waste nitrogen.
1.Sodium benzoate (Ucephan): with glycine (glycine) combine to form hippuric acid (hippurate), and then discharged by the urine. Every one mole of benzoate to remove one mole of nitrogen. Usually give the IV dose is 250 mg / kg / day; oral dose of 375mg/kg/day, minutes 3-4 times taking it and with a low-protein diet. Side effects of nausea, vomiting, tinnitus, visual impairment.
2.Sodium phenylbutyrate (Buphenyl): in the liver to be oxidized to phenylacetate, and then combined with glutamine, the final product phenylacetylglutamine discharged through the urine. 1 mole per 2 mole of phenylbutyrate to remove nitrogen. Given dose is 0.5 mg / kg / day.
3. Arginine (Arginine): by the enzyme arginase (arginase) after role, each 1mole arginine 1mole broken down into urea and ornithine 1mole of (ornithine). High blood ammonia circumstances, given doses of 600 mg / kg / day. Give children with a stable oral dose of 400-700 mg / kg / day.

Prognosis of patients and age and the condition relating to the time of diagnosis. At the neonatal period there are symptoms of the patients, their prognosis is poor, the majority of patients will have some obvious complications. Required long-term cooperation with physicians and nutritionists with the continued out-patient follow-up biochemical tests conducted on a regular basis, recording height and weight development in order to grasp the situation of patients.

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