Small jaw

Small jaw is seen in trisomy 18, also known as Edwrd syndrome. The neonatal incidence rate is 1/3500 ~ 1/8000, and the male-to-female ratio is 1: 4. The incidence rate is related to the increase of the maternal reproductive age. 18-trisomysyndrome (Edwards syndrome) is the second common chromosomal trisomy following the congenital fool type. In 1960, Edwards and others first reported a child with malformation who had an extra chromosome after chromosome examination and considered it to be chromosome 17. Many scholars have reported similar observations in succession, confirming that these clinical syndromes are related to chromosome 18 abnormalities. Hundreds of cases have been reported so far. The main clinical manifestations are multiple malformations, which die more than a few weeks after birth.