Dykens and Rosner (1999) found that 100% of those with Williams syndrome were kind-spirited, 90% sought the company of others, 87% empathize with others pain, 84% are caring, 83% are unselfish/forgiving, 75% never go unnoticed in a group, and 75% are happy when others do well. Infants with Williams syndrome make normal and frequent eye contact, and young children with Williams will often approach and hug strangers. People affected by Williams syndrome typically have high empathy, showing relative strength in reading peoples eyes to gauge intentions, emotions, and mental states. The level of friendliness observed in people with Williams is often inappropriate for the social setting, however,  and teens and adults with Williams syndrome often experience social isolation, frustration, and loneliness despite their clear desire to connect to other people.While these children often came off as happy due to their sociable nature, often there are internal drawbacks to the way they act. 76–86% of these children were reported as believing that they either had few friends or problems with their friends. This is possibly due to the fact that although they are very friendly to strangers and love meeting new people, they may have trouble interacting on a deeper level. 73–93% were reported as unreserved with strangers, 67% highly sensitive to rejection, 65% susceptible to teasing, and the statistic for exploitation and abuse was unavailable. There are external problems as well.
Prothrombin G20210A is a genetic condition that increases the risk of blood clots including from deep vein thrombosis, and of pulmonary embolism. One copy of the mutation increases the risk of a blood clot from 1 in 1,000 per year to 2.5 in 1,000. Two copies increases the risk to up to 20 in 1,000 per year. Most people never develop a blood clot in their lifetimes.It is due to a specific gene mutation in which a guanine (G) is changed to an adenine (A) at position 20210 of the DNA of the prothrombin gene. Other blood clotting pathway mutations that increase the risk of clots include factor V Leiden. Prothrombin G20210A was identified in the 1990s. About 2% of Caucasians carry the variant, while it is less common in other populations. It is estimated to have originated in Caucasians about 20,000 years ago. Signs and symptoms
The variant causes elevated plasma prothrombin levels (hyperprothrombinemia), possibly due to increased pre-mRNA stability. Prothrombin is the precursor to thrombin, which plays a key role in causing blood to clot (blood coagulation). G20210A can thus contribute to a state of hypercoagulability, but not particularly with arterial thrombosis. A 2006 meta-analysis showed only a 1.3-fold increased risk for coronary disease. Deficiencies in the anticoagulants Protein C and Protein S further increase the risk five- to tenfold. Behind non-O blood type and factor V Leiden, prothrombin G20210A is one of the most common genetic risk factors for venous thromboembolism (VTE). Increased production of prothrombin heightens the risk of blood clotting.