Question 1. What is a genetic disease? A disease that develops as a result of changes in the quantity, structure or function of genetic material in germ cells, fertilized eggs and somatic cells. Question 2. What are the types of genetic diseases? There are four major types of genetic diseases based on the mode of inheritance: chromosomal diseases, monogenic genetic diseases (including autosomal dominant, autosomal recessive, X-linked recessive, X-linked dominant, and dynamic mutagenic genes), polygenic genetic diseases, and mitochondrial genetic diseases. Question 3: What are the clinical features of genetic disorders? Mental-motor retardation, tics, nystagmus, speech disorders, behavioral abnormalities, involuntary movements, ataxia, abnormal muscle tone, myasthenia gravis and sensory abnormalities, as well as facial abnormalities, deformities of the five senses, spina bifida, bowed feet, toe deformities, skin and hair abnormalities and hepatosplenomegaly. Question 4. How are genetic disorders diagnosed? Diagnosis includes medical history, symptoms, signs, and routine ancillary tests including biochemistry, electrophysiology, imaging, and pathology; genealogical analysis; and genetic testing methods such as chromosome examination, DNA and gene product analysis. Question 5: What is the importance of genetic diagnosis for genetic diseases? Definitive diagnosis of patients, carrier detection, accurate genetic counseling and prenatal diagnosis. Question 6. How can genetic diseases be prevented? Avoiding consanguineous marriage, promoting genetic counseling, carrier genetic testing, prenatal diagnosis and selective abortion to prevent the birth of affected children. Question 7. What is prenatal diagnosis? Based on genetic counseling, various diagnostic techniques are used to make intrauterine diagnosis of fetal diseases and achieve the purpose of fetal selection through selective abortion of affected fetuses, thereby reducing the rate of birth defects and improving the quality of eugenics and population. Question 8: What is genetic counseling? Genetic counseling is the assessment of the risk rate of occurrence or recurrence of disease through the interpretation of family history; education on the genetics, laboratory testing, treatment management, and prevention of relevant diseases; and counseling to promote informed choice and progressive knowledge and acceptance of the disease suffered and its risk of recurrence. Genetic counseling is required for all individuals with indications for prenatal diagnosis.