1. �й�ҽѧ��ѧԺ���й�Э��ҽ�ƴ�ѧƤ�����о���
2. �Ͼ� �й�ҽѧ��ѧԺ����Э��ҽѧԺƤ�����о���

�ʺ�����Ǻ÷���Ӥ�׶��澱����Ѫ���Լ���������������������𽥷�չ������Ӱ�컼�ߵ���������ȷ���䲡�����Ԥ���������ʺ���롣�ʺ����Ŀ��ܲ������Ƥ��Ѫ����Χ�񾭼��١�Ѫ����Χ֧�ֽṹ���١���̥����������ϸ�����Ӹı䡢�����쳣�Լ����˵Ȼ�������ء���Ҳ������һ���ٴ�֢״�ı���֮һ��Ȼ��Ŀǰ��Щ�о��Դ��ڽϳ�ʼ�Ľ׶Σ������Ҫ������о�����ȷ�ʺ�����ȷ�в���

Port wine stains ��PWS��, which are typically located on the face and neck of infants, may enlarge and darken with age, and severely influence the psychological and physical health of patients. To explore the etiology of PWS is beneficial to its prevention and treatment. The possible etiology of PWS includes the decrease of nerve density and supporting structure around blood vessels, changes of cytokines in embryonic development, gene abnormality, trauma, etc. Also, it may be one of clinical manifestations of a syndrome. However, these kinds of studies are still in initial stage, further studies are needed to learn the exact etiology of PWS.