Patient: Regarding pigmented dry skin disease, I heard that prenatal diagnosis is possible. I would like to know what I need to prepare and pay attention to beforehand if I want to make this identification. Expert: Genetic diagnosis is performed first, which involves taking blood samples from the affected child as well as three of its parents and assessing the clinical manifestations. Since genetic diagnosis takes a long time, pregnancy is usually considered after the mutated locus is identified and amniotic fluid examination is performed at 14-16 weeks of pregnancy to determine if the fetus is normal. This technique is more mature and has a higher accuracy. Yao Zhirong, Department of Dermatology, Shanghai Xinhua Hospital In case of pregnancy before genetic diagnosis is performed, prenatal genetic diagnosis under time-critical conditions is the only option, and the accuracy rate will be reduced. In addition to staining dry skin disease, we are currently working on prenatal genetic diagnosis of hereditary epidermolysis bullosa, severe ichthyosis, neurofibromatosis, tuberous sclerosis and other lethal and disabling hereditary skin diseases.