Dopa-responsive dystonia
Introduction
Introduction to dopa-responsive dystonia Dop-reactive dystonia (DRD), also known as Segawa disease, is a rare hereditary disease that occurs in children or adolescents with dystonia or gait abnormalities as the first symptom. It is characterized by the inter-turn fluctuation of symptoms and the rapid and obvious effect of low-dose dopa preparations. Segawa et al. first described the disease in 1976, and there have been many reports in foreign countries. In recent years, it has attracted the attention of domestic clinicians. basic knowledge The proportion of illness: the incidence rate is about 0.0003%-0.0005% Susceptible people: children Mode of infection: non-infectious complication:
Cause
Cause of dopa-responsive dystonia
(1) Causes of the disease
Half of the disease is sporadic, and half of them are autosomal dominant. It is currently believed that the lack of isozyme GCHI of GTP cyclohydrolase leads to a decrease in dopamine synthesis, which is the main cause of DRD (Nagatsu 1998).
(two) pathogenesis
Foreign scholars have found that 60% to 70% of DRD patients have mutations in the GCHI coding region, located at 14q32.1, because GCHI is an important rate-limiting enzyme for the synthesis of tetrahydrobiopterin, which is an essential aid for catecholamine biosynthesis. Factor, therefore, the lack of GCHI in the nigrostriatal system dop-energy neurons inevitably leads to a decrease in tyrosine hydroxylase synthesis and ultimately a decrease in dopamine levels.
Some scholars have detected high vanillic acid and biopterin in the cerebrospinal fluid of patients with DRD, and found that the levels of the new sputum are lower than normal. The positron emission tomography (PET) examination showed that the striatum 18F-dopa intake was normal, suggesting that The disease dopa decarboxylase and dopamine receptors are normal, so a small amount of exogenous dopa preparations can be continuously administered to compensate for the deficiency of dopamine and relieve symptoms.
Prevention
Dopa-responsive dystonia prevention
Prevention is more important in people with a genetic background. Preventive measures include avoiding marriage by close relatives and implementing genetic counseling.
Complication
Dopa-responsive dystonia complications Complication
Changes in muscle tone are often unnoticed, while abnormal posture postures and involuntary transformations are more noticeable.
Symptom
Dopa Reactive Dystonia Symptoms Common Symptoms Reflexes Hypertonic Muscle Hypertension Fatigue Skeletal Neck Automatic Babin... Segmental Dystonia Horseshoe Turned torsion Gait Unsteady Limb or Torso Pose
1. The age of onset of DRD is mostly 1~12 years old, accounting for 10% of children with dystonia. A few patients can be as late as 50-60 years old (Chen et al., 1999). The incidence rate is female> male, male: female=1: 4.
2. Children with onset, most of the lower limb muscle tension is the first symptom, the child appears strange asynchronous state, lower limb stiffness, gait instability, horseshoe inversion, etc., sometimes only learn to walk later, easy to fall Downward, with the development of the disease, abnormal muscle tension affects other limbs, even the head and neck and the central axis of the body, there is a spasmodic torticollis, twisting hernia, the child may have limb tremor, muscle rigidity and automatic Babinske sign positive, language and intelligence Generally not tired.
3. Adult onset, with limb involuntary tremor, stiffness and similar Parkinson's syndrome are more common, patients with slow movement, fatigue, increased limb muscle tone, hyperreflexia, pathological signs positive, 75% of patients have symptoms The volatility of day and night, after the morning or after the break, apparently alleviated and disappeared, and the symptoms worsened in the afternoon or after exertion.
4. Most of the course of disease is progressive, and those who have not been treated will eventually be unable to take care of themselves.
Examine
Dop-responsive dystonia
1. Hematuria is routine: generally normal.
2. Cerebrospinal fluid examination: It can be normal, and it has also been reported that the content of high vanillic acid and biopterin in cerebrospinal fluid is decreased.
3. Liver function tests are normal and have differential diagnosis significance.
EEG, evoked potential, brain CT, MRI and PET examinations were all normal.
Diagnosis
Diagnosis and identification of dopa-responsive dystonia
Diagnostic criteria
The diagnosis is mainly based on clinical manifestations and responsiveness to low-dose dopa preparations. In children or adults, the first-episode symptoms such as abnormal muscle tension, tremor, and gait are unclear. The morning light weight is the main clinical feature. Especially those with a family history, should be highly suspected of this disease.
Suspicious patients are given oral low-dose dopa preparations, most of which are relieved in 1 to 3 days. If they are not effective, the dose can be increased appropriately. Foreign reports (Torbjoerna, 1991), carbidopa/levodopa dose increased to 25/100 ( Containing levodopa 100mg and carbidopa 25mg), 3 times / d, still ineffective, can rule out the diagnosis of DRD.
Differential diagnosis
The disease should be differentiated from cerebral palsy, juvenile Parkinson's disease, torsion, hepatolenticular degeneration, and spastic paraplegia.
1. Cerebral palsy: often with abnormal increase in muscle tone and sputum as the main features, but often accompanied by mental retardation, convulsions and mood disorders, no fluctuations in symptoms, no response to dopa preparations.
2. Juvenile Parkinson's disease: It rarely occurs in children under 8 years old. PET examination shows that the intake of 18F-dopa is decreased. Long-term application of Dopa preparations requires a gradual increase in dosage, and it is prone to side effects such as abnormal movement and deterioration of the agent.
3. Hepatolenticular degeneration: often accompanied by liver damage and intelligence, mental disorders, KF ring visible in the cornea.
4. A very small number of patients with initial symptoms, signs like sputum paraplegia, the dramatic response of low-dose dopa may be the most important identification point.
