Tongue-like dementia

Introduction Tongue-like dementia, also known as congenital stupid type, 21 trisomy syndrome, chromosome 13 is the germ cell in the process of meiosis, due to the influence of certain factors does not separate, the incidence rate in the birth of the baby For 1.45 , or about 1/700, the actual incidence is still high, because about half of the cases are spontaneously aborted in the first trimester, and the ratio of male to female is 3:2. It is the most common chromosomal disorder caused by autosomal aberrations. Clinical features are characterized by mental retardation, special face or other malformations. The mouth is half open, and the tongue often sticks out of the mouth and the symptoms of salivation.

Cause

The trisomy of chromosome 21 is caused by the fact that germ cells are not separated due to the influence of certain factors during the process of meiosis. The incidence rate is 1.45, or about 1/700, in the born baby, and the actual incidence is high. Because about half of the cases are spontaneously aborted in the first trimester, the ratio of male to female is 3:2. The cause is related to the age of the mother during pregnancy, hereditary factors, the use of chemical drugs abortion during pregnancy, radiation exposure, autoimmune diseases (such as chronic thyroiditis), and viral infections (such as infectious hepatitis).

an examination

Related inspection

Brain CT examination EEG examination chromosome

Chromosome examination:

(1) Trisomy 21: The karyotype of the genome is 47XX (or XY) octa 21, accounting for 90 to 95%. The total number of chromosomes in the child is 47, due to the addition of a small end-pointing chromosome (belonging to the 21st pair). This phenomenon is called trisomy because there is a pair of chromosomes that become three. When the mother is older than 35 years old, the incidence is significantly increased (about 125 times the population incidence rate). The parents have no abnormal chromosomes and no family history, so it is considered that the mother's gametes (eggs) are not separated by chromosomes. About 1/5 cases were caused by the separation of the father's chromosomes. In the case of an ovarian twin, if one is trisomy 21, 100% of the other child is also a trisomy 21 syndrome. In the case of two-oval twins, the chances of the two children being the trisomy 21 are only 30%.

(2) Translocation type: In a few cases, the total number of chromosomes is 46, and chromosome 21 still has trisomy characteristics, accompanied by distortion of other chromosomes. There are several different situations:

1. D/G translocation: The lack of a chromosome 14 adds a new chromosome, which is connected by a 21 and a chromosome 14 to form a new 14/21 chromosome. This chromosome retains most of the genetic material of chromosomes 14 and 21, so in fact, the patient's cells still have three chromosomes 21 (trisomy), and the karyotype is 46XX (or XY) 21 . t(Dq21q). This type of child accounts for 2%, and the mother's appearance is normal, but the number of chromosomes in the cell is 45, one of which is 14/21 chromosome. The aunt and the cousin of the child may have the same disease.

2, G / G translocation: 121 and 22 chromosome translocation, forming a 21 / 22 chromosome, may be inherited by the patient's father; 2 two chromosomes connected by an chromosome 21, and A normal chromosome 21, such as a mother, is 100% of its children. The karyotype is 46XX (or XY) 21, and this disease is 2%.

3. Chimera type: 1% to 2%, karyotype is 47XX (or XY) 21/46XX (or XY). Less common, the chromosomes in the cells of the sick children vary from 46 to 45 or 45. This type is mainly caused by errors in the fertilized egg during the cleavage stage. Some of the 21 triad patients had normal parental phenotypes, and had a 21 trisomy chimera, with the mother being the chimera and the father having fewer fathers. If there are more than 2 signs and 21 signs in a family, it may be related to their parents' chimera.

Differential diagnosis

Should be differentiated from dementia in other conditions.

Dementia is caused by a variety of organic factors, after the intelligence has been fairly developed, due to brain damage caused by secondary mental decline. Age is under 18 years old and does not diagnose dementia.

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