Chromosome 8 is more likely to produce abnormalities due to problems such as increasing female age, aging eggs, viral infections such as mumps and hepatitis. If chromosome 8 is missing, it may cause deformities, mental retardation, congenital diseases, slow development, etc. 1. Deformities: These include facial deformities, physical deformities and genital deformities. Facial deformities are mainly manifested as strabismus, cleft lip, drooping eyelids, and abnormal ears and nose within one year of birth; physical deformities are mostly manifested as finger flexion, patellar defects, and abnormal spinal curvature in some children; genital deformities are manifested as undescended testicles and abnormal penis shape in male children, and missing vagina in female children; 2. After birth, children with chromosome 8 deletion will have lower intelligence than their peers, which is a typical symptom of chromosome 8 deletion; 3, congenital diseases: mainly manifested as congenital heart disease, common symptoms include difficulty in breathing, poor physical strength, more cyanosis, etc., and may also have congenital disabilities; 4, slow development: children with chromosome 8 deletion have slower growth and development than normal children, mainly manifested as delayed language development and motor development. Compared to normal children, the acquisition of language comprehension and language expression skills are delayed. Chromosome 8 deletion is usually detected during maternity testing, and termination of pregnancy is recommended.