1 and 2 1 trisomy syndrome, if there is one more chromosome on chromosome 2 1, it will lead to congenital idiot.
2. 13 trisomy syndrome
The incidence rate of newborns is about 1: 25000, which is significantly higher in women than in men. Clinical manifestations: The deformity and clinical manifestations of children are much more serious than those of 2 1 trisomy (Figure 2- 18). Cranial malformations include microcephaly, forehead and forebrain development defects, small eyeball, iris defect, wide and flat nose, 2/3 children with upper lip cleft, cleft palate, low ear position, auricle deformity, small jaw, other common fingers (toes) overlapping, heel kyphosis and palm protrusion, forming the so-called rocking chair foot. Men often have scrotal malformation and cryptorchidism, while women have clitoral hypertrophy, double vagina and double horn uterus. Brain and visceral malformations are very common, such as olfactory brain, ventricular septal or atrial septal defect, patent ductus arteriosus, polycystic kidney and hydronephrosis. Deafness is caused by the defect of the spiral organ of the inner ear. All patients have mental retardation, and the degree is serious. Children who survive for a long time also have seizures and low muscle tone skills.
Trisomy 3, 18 syndrome ... 18 trisomy causes severe deformity and dies shortly after birth.
4, other chromosome trisomy syndrome
(1) More important are trisomy 8 and trisomy 22. All of them are accompanied by obvious developmental deformity and mental retardation. There are also a series of trisomy syndrome caused by translocation, and its clinical symptoms depend on the nature and size of extra chromosome fragments.
(2) Boys 2) The incidence of 2)XYY syndrome is 1: 900. XYY male has a normal phenotype, and the patient is tall, often exceeding 180cm, with occasional cryptorchidism, testicular hypoplasia, sperm process disorder, decreased fertility and hypospadias. But most men can have children. XYY individuals are easily excited, feel unsatisfied with their desires, are tired of learning, have poor self-discipline and are prone to aggressive behavior. XYY karyotype is the result that the Y chromosome does not separate when the father's sperm forms the second meiosis.
(3) Turner syndrome, also known as 45, X or 45, XO syndrome, is a female congenital gonadal hypoplasia or congenital ovarian hypoplasia syndrome. The patient's phenotype is female, short stature and normal intelligence, but she is often lower than her compatriots. Her face is triangular, with ptosis and epicanthus, narrow maxillary process, small and backward jaw, shark mouth with downward rotating mouth, and low hairline of neck, which can extend all the way to shoulders. About 50% of her patients have webbed necks, that is, redundant wing-like skin with shoulder width. There is lymphedema on the instep in infancy, which is very special. The abnormalities of genitourinary system are mainly ovarian dysplasia (gonad cord), anofollicular formation and uterine hypoplasia, and they often come to see a doctor because of primary amenorrhea. Because the pubic hair of patients with ovarian dysfunction is scarce, there is no armpit hair, and the external genitalia is childish. In addition, about 1/2 patients have aortic stenosis and horseshoe kidney malformation.
(4)47, XXX, X women's diseases are also called super girls. The incidence rate is about 0.8‰, namely 1/2250.