The main symptom of WS is fast growth and bone development (maturation). Children with WS may be tall, they have a normal or high weight for their height. A large head size (macrocephaly) is also common. Some children with WS may not show symptoms until several months after birth. People with WS may have muscles that get more rigid over time (hypertonia), especially in the arms and legs. However, the muscles in their core may be looser (hypotonia). Due to their rigid muscles, individuals with WS may have poor coordination. Babies with this syndrome have a hoarse and low-pitched cry.
People with WS may have eyes that are far apart (hypertelorism), extra skin over the inner corner of the eyes (epicanthal folds) or eyelids that slant down (down-slanting palpebral fissures). The back of the head (occiput) may be flat, the forehead wide and the ears larger than usual. The groove located above the upper lip and below the nose (philtrum) may be longer than average. People with WS may have a smaller jaw than normal (micrognathia). Other physical features can include thin hair, inverted nipples and loose skin.
People with WS usually have wide thumbs. One or more fingers may be permanently bent (camptodactyly). Nails may be deep-set and thin. The pads of the fingertips are usually raised. People with WS may have differences of the feet. These may include misshapen toes (clinodactyly), a very high arch of the foot (pes cavus), a clubfoot or a twisted foot (metatarsus adductus). The clubfoot may have the sole of the foot turned inward and upward towards the heel (talipes equinovarus) or towards the toes (talipes calcaneovalgus). People with WS may not be able to fully extend their elbows or knees.
Other symptoms associated with WS include varying levels of intellectual ability, from normal intelligence to severe intellectual disability. There also seems to be an increased chance for umbilical hernias and, more rarely, a type of brain cancer called neuroblastoma.