Chromosomal abnormalities?
summary
Down's syndrome is also known as trisome 21 syndrome and congenital stupidity. This is the most common chromosome disease in human beings. The incidence rate of neonatal 1/700 ~ 1/600 is the most common cause of mental retardation, accounting for 10% of the cases of severe mental retardation. Seguin (1846) first reported the clinical manifestations of the disease. Langdonedown (1866) gave a comprehensive description of the disease. British scholars later called the disease Down syndrome. Lejeune et al. (1959) proved that the disease was caused by chromosome 21 triploidy, and advocated the name of trisomy 21 syndrome, which was recognized at Denver conference in 1970. Chromosomal abnormalities? Let's talk about it
Chromosomal abnormalities?
(1) Children with Down syndrome have some pathological features at birth, and the symptoms become obvious with age. Craniofacial manifestations of round head, low bridge of nose, maxillary hypoplasia can lead to flat face, mouth is slightly open, tongue hypertrophy with deep fissure, often extending out of the mouth, so it is called tongue like dementia. Epicanthus often covers part of the inner canthus, patients with palpebral fissure can be slightly upward, outward tilt, the formation of Mongolian appearance. The position of the ear is low, oval, the earlobe is small, the iris is gray white spots, namely Brushfield's spots, the fontanel is obvious, and the closure is late.
(2) the average body length of the infants at birth is slightly shorter than that of the normal newborns, and the difference becomes more obvious with the increase of age. The height of the adult patients is rarely higher than that of the normal 10-year-old children. The hand is short and thick, the palm is wide, and there is only one horizontal line, which is manifested as horizontal palmar fold (through the hand) and other characteristic dermatoglyphic changes, such as short and inward flexion of the little finger, showing a single fold (that is, the fifth finger is two segments). Most of the children were still unable to walk when they were 3-4 years old. Moro in infants is slow to respond or cannot be induced, and it is difficult to eat. Intelligence and mental development of the children were obviously abnormal. IQ ranged from 20 to 70, with an average of 40 to 50. Most of them were below the Gaussian curve. 90% of the children would speak when they were 5 years old. Most of them are quiet, docile, approachable and can live up to 40 years.
(3) Some patients can see cataract, congenital heart disease or heart disease secondary cerebral embolism and brain abscess, gastrointestinal abnormalities such as duodenal stenosis, atlantoaxial instability, severe exercise can lead to spinal cord compression, the incidence of myeloblastic and lymphoblastic leukemia is higher than ordinary people. Alzheimer's disease was almost common in patients over 40 years old, including inattention, lack of speech, poor visual spatial orientation, decreased memory and judgment, and seizures.
matters needing attention
About half of spontaneous abortions are caused by chromosomal abnormalities. Due to the variation and poor quality of sperm, the result of pregnancy is often repeated pregnancy and abortion. In fact, this is the need of natural selection and eugenics. Chromosomal abnormalities are not limited to men, but also to women.
