PB1078 - Severe Thromboembolic Events in A Patient With Protein C and Protein S Heterozygous Deficiencies

Background: Protein C and protein S deficiency are rare diseases. Coexistence of these two conditions is much rarer.

Aims: We present here a pediatric patient with protein C and Protein S mild deficiency and additional congenital thromboembolic risk factors.

Methods: A twelve-year-old male patient was admitted to the hospital with a complaint of pain in the left leg. It was noticed that he did not move his left arm after birth, and an infarct was detected in the brain MRI. Physical examination revealed that his left arm was weak and had muscle atrophy. There was edema, temperature increase, and pain in the left leg. A thrombus was detected in the femoral vein on Doppler ultrasonography. Low molecular weight heparin (LMWH) treatment dose was started.

Results: Thrombus risk factors were investigated. Protein C and S levels were found to be slightly low, and the decrease continued in repeated examinations. Factor V Leiden mutation was found to be heterozygous. Protein S was slightly low in the mother, and protein C was slightly low in the father. Factor V Leiden mutation in the father was found to be heterozygous. In addition, the patient's VIII level was found to be very high. mutation in the pros gene was shown. Heterozygous c.263G>T (p.Cys88Phe) mutation was observed in PROS1 gene. Heterozygous c.709G>C (p.Ala355Val) mutation was observed in PROC gene.
When the LMWH dose was reduced to the prophylaxis dose, the patient developed pulmonary embolism and was treated urgently. Our patient is 30 years old and still uses LMWH at the treatment dose. He plays begminton for the disabled team due to weakness in his left arm. He graduated from sports university, became a sports teacher.

Conclusion(s): Protein C and S heterozygote deficiency, factor V Leiden heterozygous mutation, and factor VIII higher application are a very high risk for thromboembolic events.