Huntington's disease dementia

Introduction to Huntington's disease dementia Huntington's disease dementia was first reported by Huntington in 1872, hence the name. It is a single-gene autosomal dominant genetic disease with a wide range of brain degeneration, especially atrophy of the caudate nucleus. It is a rare idiopathic neurodegenerative disease, and its clinical manifestations are dementia and dance-like movements. basic knowledge The proportion of the disease: the incidence rate is about 0.006% - 0.008%, more common in the elderly over 60 years old Susceptible people: good for people aged 30-50 Mode of infection: non-infectious complication:

Cause of Huntington's disease dementia

(1) Causes of the disease

The molecular genetics of Huntington's disease dementia is one of the remarkable achievements of molecular biology in neuroscience in recent years. It is also a milestone in the application of molecular biology in clinical medicine. Huntington's disease dementia is a single gene autosomal dominant inheritance. In 1983, Gusella et al. found a DNA marker G8 closely linked to Huntington's disease dementia from a human DNA fragment cloned with a phage vector. This marker G8 is located on the fourth pair of chromosomes, further The study also determined that the defective gene for Huntington's disease dementia is located in the short arm 4P16 region of chromosome 4.

In China, a total of 151 patients from 15 families were reported from 1958 to 1985, and only 1 of them had no family history.

The pathological changes of the disease are symmetrical atrophy of the brain. The atrophy of the frontal and caudate nucleus is obvious, the ventricular system is enlarged, the caudate nucleus is severely atrophied, and the curved part of the lateral ventricle is concave. The microscopic examination is more common. Cortical nerve cells are extensively lost, accompanied by gliosis, tail nucleus, lenticular nucleus and white matter also have nerve fiber loss.

In the basal ganglia of patients with Huntington's disease dementia, the level of GABA in the substantia nigra is decreased, the GABA synthase of the lenticular nucleus and the globus nucleus, glutamate decarboxylase (GAD) is also significantly reduced, the ChAT of the striatum is reduced, and the striatum and substantia nigra DA With elevated NE levels, excessive striatum DA activity may be associated with involuntary movement, and increased DA in the midbrain limbic system may be associated with mental symptoms of Huntington's disease dementia.

(two) pathogenesis

The disease is usually a single gene autosomal dominant inheritance, there are also a few sporadic cases reported, the genetic gene was identified on the short arm of chromosome 4, single gene dominant inheritance suggests that the disease is a congenital metabolic deficiency disease, pathogenesis It is interpreted as a change in different neurotransmitters, which is associated with a decrease in GABA levels in the basal ganglia, substantia nigra, and an increase in DA and NE levels in the striatum and substantia nigra. Pathological changes are mainly atrophy of the frontal and caudate nucleus. Leaf nerve cells are significantly lost and accompanied by glial cell formation.

Huntington's disease dementia prevention

Because this disease is a single-gene autosomal dominant genetic disease, patients and their families rarely know that their children are at risk of developing the same disease. Therefore, early genetic counseling services are important. Hereditary diseases are hereditary and life-long. The characteristics not only bring misfortune to the family, but also cause lifelong pain to the patients, and pass the disease from generation to generation. In order to control and reduce the occurrence of hereditary diseases, it is necessary to do the prevention first, and implement the eugenics protection method. Those who may cause congenital diseases in future generations should avoid birth. At present, China is formulating a eugenics protection law to prohibit the marriage of close relatives. "Pro-family-friendly" will increase the incidence of some genetic diseases. China's Marriage Law has explicitly prohibited close relatives from marrying. Avoiding old-age births, for older breeders (women over 35 years old, male over 45 years old), should have a prenatal diagnosis, a history of genetic disease, a child with a deformed child or a history of multiple abortions, genetic counseling should be carried out through genetics Consultation, do the necessary prenatal diagnosis for some pregnant women with indications, if found to have serious diseases, can terminate the pregnancy in time to prevent Heavy disease and birth defects.

Huntington's disease dementia complications Complication

The disease causes declining quality of life due to dementia, so it is easy to suffer from various chronic physical diseases and secondary systemic infection or failure.

Huntington's disease dementia symptoms common symptoms dementia mental retardation forgetfulness provoke depression aphrodisiac personality change childlike dementia mutism illusion

The disease usually occurs between the ages of 30 and 50, with an average of 40 years old. It rarely occurs in childhood, but the variation is large, ranging from childhood to childhood, and the symptoms of young people are often heavier. The clinical manifestations are Movement disorders and obvious and diverse spiritual changes.

1. Neurological symptoms: Dance-like symptoms usually appear before the mental retardation. In the early stage, the irregular muscles are often twitched, showing the flexion and extension of the fingers, nodding, facial muscle twitching, and further development into the face, neck, limbs and trunk. Suddenly, no purpose, strong involuntary dance-like movements, characterized by rapid and irregular, sudden and sometimes slow and rhythmic movements like hand and foot hyperactivity, accompanied by unclear pronunciation and gait changes, cones can also appear In vitro symptoms, patients often use the same direction of random movement to pseudo-decoration, it belongs to an extrapyramidal syndrome with weakened muscle tone and enhanced motor function. The abnormal movement increases the drama leading to obvious twist-like movements and ataxia, dance. Mental disorders tend to worsen after symptoms appear.

2. Psychiatric symptoms: highlighting emotional disorders, especially depression, emotional apathy, dullness, depression, often suicidal behavior or personality changes, bad temper, like quarrel, distraction, etc., some patients may have paranoid spirit Schizophrenic clinical signs and schizophrenia-like symptoms, suspicion of suspicion, often exaggerated and religious color and personality changes, such as irritability, impulsivity, fury, behavioral quirks, etc. Huntington's disease dementia often has depressive symptoms and obvious suicidal tendencies .

Mental retardation can sometimes be used as a first symptom. Early patients have distracted attention, can be dull, passive, indifferent, lazy, poorly understood, work efficiency is down or unable to do the job, etc., afterwards, symptoms of dementia, slow development, early life ability Decline, have a certain degree of self-knowledge, self-reported slow thinking, forgetfulness, memory impairment is lighter than AD, judgment is often impaired, relative orientation is relatively maintained, speech is difficult, misuse, misrecognition is rare, late movements are incapable of silence and stupidity. Often progress slowly, the patient's memory is less affected than other cognitive functions, the self-knowledge is often kept intact, the patient can detect his intellectual changes for a period of time, the complaint is slow, forgetful, the brain is confused, is regarded as "cortex Under the dementia, in the late stage, there may be obvious motor inability to mutism.

Huntington's disease dementia check

Psychological examination is an important method to diagnose the severity of dementia and dementia. In recent years, many internationally simple and rapid screening tools have been introduced and revised in China. The diagnostic validity, sensitivity and specificity are high. as follows:

1. Mini Mental State Examination (MMSE) Prepared by Folstein in 1975 to assess the scoring criteria. If the answer or operation is correct, record "1", the error is "5", refuse to answer or say "no". 9" or "7", the main statistics of the "1" project sum (MMSE total score), the range is 0 ~ 300 international standard 24 divided into cut-off values, 18 ~ 24 for mild dementia, 16 ~ 17 for moderate dementia, 15 is divided into severe dementia. China has found that the critical value is different due to different educational levels; illiterate is 17 points, primary school (educational years 6 years) is 20 points, and middle school and above is 24 points.

2. Hasegawa Dementia Scale (HDS) Developed by Hasegawa Kazuo in 1974, a total of 11 projects, including orientation (2 items), memory (4 items), common sense (2 items), calculations ( 1 item), remember the naming memories (2 items).

The scale uses positive score method, the full score is 32.5 points, the original author's critical value is: dementia 10.5 points, suspicious dementia 10.5 ~ 21.5 points, edge state 22.0 ~ 30.5 points, normal 31.0 points, can also be educated The degree is divided into normal values: illiterate 16 points, primary school < 20 points, secondary school < 24 points.

3. Activity of Daily Living Scale (ADL) Developed by Lawton and Brody in 1969, it is mainly used to assess the daily living ability of subjects.

The ADL is divided into 14 items and the score is 4:

1 You can do it yourself;

2 is somewhat difficult;

3 need help;

4 can not do, 64 points full score, total score 16 points is completely normal, > 16 points have different degrees of functional decline, single item 1 is divided into normal, 2 to 4 points function is reduced, there are 2 or more than 3 Or the total score 22 is the critical value, suggesting that the function has significantly reduced, the conventional total score in China is 18.5 ± 5.5.

Cranial CT and MRI showed atrophy of the caudate nucleus, and positron emission tomography (PET) showed a markedly low metabolism of the caudate nucleus.

Diagnosis and identification of Huntington's disease dementia

Diagnostic criteria

In recent years, domestic intelligence reports accounted for 46% to 64% of mental disorders, of which 4.5% were the first symptoms. Psychological tests Huntington's disease dementia patients not only have poor ability to work, memory, problem-solving ability, concept formation, speech retention ability and other cognitive functions. Also reduced, the disease has no aphasia, disuse, misidentification and other characteristics of advanced cortical dysfunction, can help identify with AD.

1. Have a clear history of genetic disease or clear evidence of brain lesions.

2. Progressive dementia.

3. Psychiatric symptoms: mainly depression, apathy, euphoria, hallucinations and delusions.

4. Dance-like movements appear before dementia.

Differential diagnosis

1. Early misdiagnosis as schizophrenia, affective psychosis, anxiety, personality disorder, the identification point is a clear family genetic history, evidence of brain degeneration and subsequent dance-like symptoms.

2. Identification with other brain degenerative diseases should be based on medical history, clinical manifestations, neurological examinations and laboratory tests.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.