pediatrics
Trisomy 18
Symptoms and Signs of Trisomy 18
Typical findings on prenatal ultrasonography and other fetal testing include polyhydramnios, small placenta, a single umbilical artery, and fetal growth restriction. Birth weight is low, and there is hypotonia and marked hypoplasia of skeletal muscle and subcutaneous fat. The cry is weak, and response to sound is decreased. The orbital ridges are hypoplastic, the palpebral fissures are short, and the mouth and jaw are small; all of these characteristics give the face a pinched appearance. Microcephaly , prominent occiput, low-set malformed ears, narrow pelvis, and a short sternum are common. A clenched fist with the index finger overlapping the 3rd and 4th fingers often occurs. The distal crease on the 5th finger is often absent. Redundant skinfolds, especially over the back of the neck, are common. The fingernails are hypoplastic, and the big toe is shortened and frequently dorsiflexed. Clubfeet and rocker-bottom feet are common. Severe congenital heart disease is common, especially Patent Ductus Arteriosus (PDA) and Common muscular manifestations include hernias, separation of the rectus muscles of the abdominal wall, or both. This photo shows the hand of an infant with trisomy 18. Note the clenched fist and postaxial polydactyly. Image courtesy of Nina Powell-Hamilton, MD, FAAP, FACMG. Image courtesy of the Centers for Disease Control and Prevention Public Health Image Library. Image courtesy of the Centers for Disease Control and Prevention Public Health Image Library. Image courtesy of the Centers for Disease Control and Prevention Public Health Image Library. 