What Is a Chromosome Disorder?

Chromosomal disorders are diseases with abnormal numbers of chromosomes and / or structures caused by various reasons. Due to the large number of genes on the chromosome and the pleiotropic nature of the gene, chromosome diseases often involve abnormalities in the shape and function of multiple organs and systems. Clinical manifestations are diverse and often manifest as syndromes. Genetic disease. Those with severe chromosomal aberrations die early in the embryo and have a spontaneous abortion. A few people with chromosomal aberrations can survive to birth, often causing multiple malformations, mental retardation, retarded growth and development, and multiple system dysfunction. Chromosome disease is not an effective treatment, so it is important to prevent chromosome disease through genetic counseling and prenatal diagnosis.

Basic Information

nickname: Chromosome aberration syndrome
English name: chromosome disease

Visiting department: Reproductive Genetics
Common causes: Severe poison pollution, close marriage, etc.

Chromosome aberration

Chromosome aberrations include two types of abnormal chromosome numbers and structural abnormalities.

Abnormal number of chromosomes

Because the chromosomes do not separate during meiosis or mitosis, the inherent number of 46 chromosomes increases or decreases.

2. Abnormal chromosome structure

The basis for this is a break, which fails to reconnect in situ after the break, resulting in chromosomal rearrangements and causing various types of chromosome structural aberrations. Common structural aberrations in clinical are: deletion, translocation, inversion, insertion, circular chromosome and isocharm chromosome.

Causes of chromosome disease

1. Maternal age

The older the mother is, the more likely the offspring will develop chromosomal disease, which may be related to the aging of the mother's eggs.

2. Physical factors

X-ray radiation and ionizing radiation can induce chromosome aberrations, and the distortion rate increases with the increase of radiation dose.

3. Chemical factors

Many chemical drugs (such as anti-metabolic drugs, anti-epileptic drugs, etc.) and pesticides and poisons (such as benzene, toluene, arsenic, etc.) can cause increased chromosomal aberrations.

4. Biological factors

Viral infections such as Toxoplasma gondii, cytomegalovirus, EB virus, mumps virus, rubella virus, hepatitis virus and other infections can cause fetal chromosome aberrations.

Clinical manifestations of chromosome disease

Chromosome karyotype analysis should be considered if: suspected of having a chromosome disease; have a variety of congenital malformations; obvious growth and development disorders or mental retardation; abnormal sexual development or incompleteness; Older age, primary infertility or multiple spontaneous abortions.

Autosomal

Among autosomal diseases, trisomy syndromes and some trisomy syndromes are common. Patients often have growth retardation, mental retardation and obvious congenital multiple malformations, commonly known as "triple sign." Among autosomal diseases, 21-trisomy syndrome is the most common, followed by 18-trisomy syndrome, 13-trisomy syndrome, and 5p syndrome.

Sex chromosome disease

It refers to a disease caused by abnormal X or Y chromosome structure or number. The common clinical features of these diseases are sexual dysgenesis or hermaphroditism, and some patients are characterized by primary amenorrhea, decreased fertility or poor intelligence. The clinically representative chromosomal diseases are gonadal dysgenesis and congenital testicular dysplasia.