Palm print atd angle greater than 45°
Introduction
Introduction The palmprint atd angle greater than 45° is a special appearance of the congenital type (21III sign, Down syndrome) of mental retardation caused by chromosomal abnormalities. About 40% of patients have this symptom. Mental retardation refers to the mental function of individuals who are mentally retarded, mentally retarded or blocked due to mental retardation, mental retardation or obstruction before maturity (before 18 years of age), accompanied by social adaptation difficulties. A syndrome characterized by a major feature. The IQ of the patients is between 50 and 69 years old, accounting for about 80% of MR. It is not easy to be detected in the early stage. In the early childhood, there may be language and motor function development, and there is no obvious abnormality in the development of the body and nervous system.
Cause
Cause
(1) Causes of the disease
There are two main reasons for mental retardation:
1 genetic factors;
2 environmental factors.
Genetic factors include chromosomal aberrations and hereditary metabolite monogenic diseases; environmental factors include pregnancy, adverse factors during birth and harmful factors in newborns and infants.
In addition, due to the early cultural and emotional deprivation, lack of appropriate stimulation, long-term neglect and isolation, living in remote poverty, cultural backwardness, and inaccessible areas. The degree of mental retardation caused by general psychosocial factors is relatively low. Once the unfavorable factors are eliminated, it is possible to improve their intelligence level. The improvement depends on the age of the child, the degree of damage and the conditions provided by the environment.
(two) pathogenesis
Genetic factor
(1) Chromosomal aberrations: including changes in number and structure. Changes in numbers such as polyploidy, aneuploidy: structural changes such as chromosome breaks, deletions, duplications, inversions and translocations. The most common type of Down syndrome is the disease caused by the 2l autosomal trisomy. Another type of chromosomal aberration in this disease is ectopic, such as G/D translocation and G/G translocation. Down syndrome is a common cause of mental retardation. Other chromosomes, such as the 18-triad sign, and the absence of the short arm of chromosome 5 can cause more serious mental defects and physical deformities. Patients often die early. Prader Willi syndrome is characterized by small stature and short stature, varying degrees of mental retardation and strong desire for eating, mainly due to small deletions in chromosome 15q11~q13, and a few families are unbalanced translocations.
Sex chromosome aberrations: such as congenital testicular hypoplasia (Klinefelter syndrome) is an X chromosome for men. If a woman loses a sex chromosome X, she presents with congenital ovarian hypoplasia (Turner syndrome). There is also a karyotype of XXX or XO/XXX chimera. It is generally believed that the more sex chromosome X aberrations, the more severe the mental impairment. The chimera generally has relatively less intellectual damage. The fragile site of chromosomes is associated with X-linked mental development. On the X chromosome, Xq27, 28 appeared in the fragile site and showed special clinical features combined with mild mental retardation to constitute a clinical special type called fragile X syndrome.
This is another disease caused by autosomal changes after Down syndrome. There are only case reports in China and there is no epidemiological data of this disease, but Jin Ming et al (1984) performed chromosome fragile site examination on 70 children with mental retardation. The result was 54.3% positive and distributed in the X chromosome. Outside the groups of autosomes. Li Sushui et al (1997) performed chromosomal fragility sites and fragile X chromosome examinations in 90 children with mental retardation with autism. The detection rates of fragile sites were 20% and 38%, respectively, and the fragile X chromosome was not found.
(2) Inherited metabolic single-gene disease: Single-gene genetic diseases are more common. 1% of life-infested infants, and about 4,000 to 5,000 human diseases. Among them, 300 species are damaged by brain function caused by abnormal biochemical metabolism. Usually, about 25% of the clinical symptoms of monogenic diseases are already present at birth, and 90% have appeared in early adolescence. Such as phenylketonuria and several neurocutaneous syndromes. Neurofibromas are a common type. The prevalence rate is 1/5000 to 1/4000. Phenylketonuria is a typical representative of hereditary metabolic defects.
The lack of congenital phenylpyruvate hydroxylase can not oxidize phenylpyruvate to tyrosine, resulting in the accumulation of a large amount of phenylpyruvate affecting the development of the central nervous system and normal physiological functions. Another example is galactosemia, because the process of converting 1-galactose to glucose 1-phosphate is blocked or lactose accumulates in the blood and tissues, causing damage to various organs such as liver, kidney and brain, in addition to the body caused by it. In addition to the symptoms, the child also has mental impairment.
2. Environmental factors contain broad environmental factors:
(1) Harmful factors during pregnancy and childbirth: It is estimated that the harmful factors of pregnancy and delivery have an impact on mental retardation accounting for 10% to 20% of the total, while postpartum injury accounts for 5% to 10%. The main harmful factor during pregnancy is infection, especially in early pregnancy. For example, 15% to 20% of babies born to pregnant women infected with cytomegalovirus and herpes simplex virus in the first 3 months of pregnancy have congenital malformations. The former incidence rate is about 1/3000. It is characterized by small head, mental retardation, hydrocephalus and epilepsy. Another noteworthy is the toxoplasma, protozoa, which are mostly infected by pregnant women. The effects of harmful physicochemical substances on the fetus also occur in early pregnancy. For example, improper use of drugs, radiation, industrial pollution caused by heavy metals such as mercury and lead, water quality and air exceeding the standard may lead to damage to the normal development of the fetus.
Alcohol and nutrition are another important detrimental factor (Nico Bkichrodt, 1989; Yang Xiaoling, 1999). About 10% to 15% of babies born to chronic alcoholics are fetal alcohol syndrome. Clinical symptoms include undergrowth, facial deformity, cognitive impairment, mental retardation, and some limb and skeletal abnormalities, often accompanied by attention deficit disorder.
In some areas, the result of iodine deficiency can cause serious mental retardation. The contamination of lead in gasoline and paints and coatings is also quite severe in some areas and may have an impact on the fetus. Studies have suggested that cognitive and behavioral disorders may occur when blood lead levels are 10 to 25 U/dl. In the mid-1980s, nearly 10% of preschool children in the United States had blood lead levels of 20 U/dl, while in low-income families, about 20% of children had blood lead levels of 30 U/dl. Therefore, the country in the development of urban industry is a harmful factor that cannot be ignored.
The health of pregnant women directly affects the normal development of the fetus. Serious chronic diseases such as heart disease, diabetes, high blood pressure, chronic kidney disease and severe anemia can cause fetal ischemia and hypoxia, leading to immature children, intrauterine growth retardation, low birth weight or nervous system damage, intrauterine asphyxia And intracranial hemorrhage. The effects of maternal disease on the fetus account for about 6% of the newborn, and about one-fifth of them are severe. Signs of poor prognosis in the neonatal period include Apgar scores below 6 or 7, early seizures and the like.
(2) Harmful factors in neonates, infants and young children: It is estimated that 5% to 10% of mental retardation is related to such factors. Including neonatal, severe poisoning, infection, hypoxia, trauma, malnutrition and psychosocial factors, such as epidemic encephalitis. Various infections caused by toxic encephalopathy, hemolysis caused by various causes, increased bilirubin, Rh factor hemolysis, drug-induced hemolysis, hypoxia caused by various causes, such as severe convulsions, severe congenital heart disease.
Examine
an examination
Related inspection
Infant intelligence test neurological examination
The palm print can be divided into three main areas: the big fish, the small fish and the inter-finger area. The big fish is located below the thumb. The small fish is located below the little finger of the palm. There is a three-pronged point at the base of the second to fifth fingers, which are sequentially labeled as a, b, c, and d. Under the palm, under normal circumstances, at the bottom of the big and small fish, near the middle of the base of the palm, there is a trigeminal point, called trigeminal t. From the point t to the line connecting a and d, an angle is called the atd angle.
The atd angle of a normal person is generally indicated by "t", and the average atd angle of a normal person in China is about 41°. However, in some patients with genetic diseases, the trigeminal t site changes in the position where the hand is resident, so that the atd angle is abnormal. The abnormal atd angle is represented by "t'" and "t", 46° < t' < 63 ° < t". For example, the average value of at'd angle of patients with congenital type is about 70°. The occurrence of the trigeminal point t' is 2% in normal people, 82% in congenital type, 3% in normal people, and 25% in 13 trisomy, and 13 in 13 81%, 5P-patients were 80%.
Diagnosis
Differential diagnosis
Palmprint inheritance is polygenic and has individual specificity. It develops at the 13th week of the fetus and is completed at the 19th week. Once formed, it remains unchanged for life and has high stability. Even if they are twins, although the overall structure looks exactly the same, there are always some differences, and the detailed figures are not identical.
Some abnormal palm prints are significantly associated with genetic diseases and can be used for primary screening and assisted diagnosis of genetic diseases, especially chromosomal diseases. The way palms are judged is as follows:
1. Judging by fingerprint shape
There are three types of fingerprints on the outer side of the fingertips and the number of the three forks: bow, crepe and bucket (the so-called trigeminal is the three pairs of different lines of the fingerprint in the fingerprint gathered in a place of "Y" or "human" "Glyph".
Bow pattern: This is the simplest fingerprint pattern, which is characterized by all of the arcuate parallel textures, the lines of which run from one side to the side, and the middle ridges are arched, without trigeminal points.
-shaped pattern: China's common name is , its ridge line starts from one side, bends upward and then returns to the original side, which looks like . At the opening of the , that is, on the side of the shin, there is a directional line in a three-direction shape, which is called a trigeminal point. According to the different orientation of the opening of the crepe pattern, it can be divided into the or the ulnar side and the or side . The right opening is facing the little finger of the hand, the fingerprint printed on the left hand is directed to the right, and the opening printed on the right hand is directed to the left.
Bucket pattern: including ring, spiral, capsule, twisted, deformed, deformed and so on. Rings, spirals and sacs are commonly known as buckets. The twisted and deformed shape is also called double twist. These types all have two trigeminal points that are listed together in the bucket pattern.
Normal people's fingerprints have a certain frequency of occurrence. Normal people's fingerprints are mostly positive and bucket-shaped, while arched lines and rumors are rare. However, the incidence of fingerprints in patients with genetic diseases is abnormal. For example, in the normal population, the rumors of the 4th and 5th fingers only accounted for 0 to 1%, while the congenital patients were mostly ruminant. The total number of fingerprints in the hands of the bow is greater than 7, which is only about 1% in the normal population and as high as 80% in the 18 trisomy. The total number of fingerprints in the hands is greater than 8 for the bucket pattern, only 8% for the normal population, and 32% for the 5P-patient (cat calling syndrome). The above cases are changes in the skin texture of patients with chromosomal diseases. Single-gene and polygenic genetic diseases also have certain changes in dermatoglyphic changes: ulnar sacral stenosis increases in patients with atrial septal defect (a common congenital heart disease); sacral sacral striate increases in patients with atrial septal defect; In patients with schizophrenia, the striate lines increased, and the striate lines decreased.
2. Judging by palm pleats
Palm pleats are pleats that connect the skin to the deep fascia. There are three main pleat lines in the palm of a normal person: the large fish pleat line, the proximal horizontal pleat line and the distal horizontal pleat line. The three positional relationship: the proximal transverse pleats are connected to the large fish creases on the temporal side, and the distal transverse pleats are separated.
There is a type of palm pleat that is said to pass through the hand, that is, the far and near side pleats form a pleat across the entire palm. People with both hands are only 2% in the normal population, 31% in the congenital type, 25% in the 18 trisomy, 62% in the trisomy, and 35% in the 50% of the patients.
3. Total number of crepe lines
The crepe count refers to drawing a straight line from the center point of the crepe or bucket pattern to the center of the trigeminal point, and then calculating the number of crepe lines that the line passes through. Add the number of crepe lines of the 10 fingers of the left and right hands to obtain the total number of crepe lines (TRC for short). Since the bucket pattern has two trigeminals, two numbers are calculated separately, but only the larger number is counted when calculating the total number. The bow line has no trigeminal and the number of crepe lines is zero.
The appearance of dermatoglyphosis in patients with sex chromosome variation is the relationship between TRC and the number of sex chromosomes: for each X chromosome added, the TRC value is reduced by 30; when a Y chromosome is added, the decrease is 12. For Turner syndrome, the patient's TRC value increased significantly (60 to 203), compared with 127 for normal women; Klinefelter syndrome patients with decreased TRC values, there is another phenomenon: increased bow lines.
As can be seen from the above, genetic diseases are often abnormal in dermatoglyphics, and the analysis of dermatoglyphics can be used for genetic diseases, especially for primary screening and auxiliary diagnosis of chromosomal diseases. However, because normal people sometimes see abnormal skin lines, the diagnosis of genetic diseases must be combined with other diagnostic indicators to make a conclusion.
