患者，男，49岁，2022年1月至温州医科大学附属舟山医院就诊，自诉1月余前无明显诱因下出现行走不稳，后症状持续存在。该患者既往有血栓性静脉炎，无动脉或静脉血栓家族史；有2次急性脑梗死发作史，于上海交通大学医学院附属瑞金医院行易栓症相关检测，发现蛋白S总量为26.7%，基因检测结果为蛋白S的编码基因 PROS1第15号外显子发生c.1955A>T，p.Asp652Val杂合突变。该患者被诊断为遗传性蛋白S缺乏症（protein S deficiency，PSD），之后长期口服利伐沙班片抗凝。此次查体除行走稍不稳外，其余无明显异常；静脉血栓栓塞症（venous thromboembolism，VTE）风险评估量表（Padua模型）评分为6分，判定为VTE高危患者。动态心电图显示窦性心律，偶发房性早搏、室性早搏；四肢血管B超显示双侧腘动脉、胫后动脉多发血栓形成伴局部狭窄，右侧桡动脉闭塞；心脏超声及颈动脉超声未见明显异常；颅脑MRI结果显示左侧基底节区脑梗死陈旧性病灶。CT血管造影联合三维重建显示左侧大脑中动脉M1段重度狭窄、闭塞可能，两侧颈内动脉虹吸段狭窄、硬化。该患者最终被诊断为PSD合并脑梗死及外周动脉阻塞。治疗采用瑞舒伐他汀钙片调脂稳定斑块，利伐沙班片抗凝，琥珀酸美托洛尔缓释片控制心室率，叶酸片改善代谢；治疗10 d后，患者症状好转。

The patient, a 49-year-old male, was admitted to Zhoushan Hospital Affiliated to Wenzhou Medical University in January 2022. He complained of walking instability without obvious inducement for more than 1 month. He had a history of thrombophlebitis and no family history of arterial or venous thrombosis. He had two episodes of acute cerebral infarction, and the tests for thrombophilia in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine showed that the total amount of protein S was 26.7%, and he had a heterozygous mutation C.1955A>T, p.Asp652Val in the exon 15 of PROS1 gene. Then he was diagnosed as having hereditary protein S deficiency (PSD), and thereafter he was given long-term oral rivaroxaban tablets for anticoagulation. This time the physical examinations showed no abnormalities except slightly unsteady walking. The patient scored 6 points in the Venous Thromboembolism (VTE) Risk Assessment Scale (Padua model) with high risk of VTE. Holter testing showed sinus rhythms with occasional premature atrial beats and premature ventricular beats. B-ultrasound for the vessels in the extremities showed multiple thrombus formation with local stenosis in the bilateral popliteal arteries and the posterior tibial arteries, and occlusion in the right radial artery. Echocardiography and carotid ultrasound showed no obvious abnormalities. Cranial MRI showed an old cerebral infarction lesion in the left basal ganglia region. CT angiography combined with three-dimensional reconstruction showed severe stenosis and possible occlusion in the M1 segment of the left middle cerebral artery, and stenosis and sclerosis of the siphon segment of the bilateral internal carotid arteries. Finally, the patient was diagnosed as having PSD with cerebral infarction and peripheral arterials obstruction. He was treated with rosuvastatin calcium for stabilizing plaques, rivaroxaban for anticoagulation, metoprolol succinate for controlling ventricular rhythms, and folic acid for improving metabolism. After 10 d of treatment, the patient 's symptoms were improved.