BACKGROUND: Protein S deficiency, which exists in 0.7% of the population, is a risk factor for retinal vein branch occlusions and is inherited in an autosomal dominant manner. METHODS: A genealogical study was carried out on three generations of one family who exhibited different venous occlusions and subsequent complications. RESULTS: Four members of the family, spanning three generations, suffered from complications of venous thrombosis. In the first generation a great uncle died of complications from a deep leg venous thrombosis. In the second generation, the mother underwent a venous branch thrombosis at the age of 41 with a protein S activity of 18%. Subsequently, a palsy of the N. abducens developed with multiple cerebral lesions (presumably post-thrombotic) in the MRI. Fluorescein angiography showed a typical picture of a venous branch occlusion which had been treated by laser. In the third generation, the 16-year-old daughter developed iliac venous thrombosis and a pulmonary embolism with a protein S activity of 0%. The fluorescein angiography showed distinctively engorged veins. A 28-year-old daughter, with a protein S activity of 16%, remained asymptomatic, although fluorescein angiography demonstrated engorged veins. Protein C activity and APC resistance of all family members were normal. The chromosomal analysis of the family members revealed no morphological aberrations. CONCLUSION: Protein S deficiency increases the risk of congenital thrombosis in young and middle-aged heterozygous individuals.
BACKGROUND:Protein S deficiency, which exists in 0.7% of the population, is a risk factor for retinal vein branch occlusions and is inherited in an autosomal dominant manner. METHODS: A genealogical study was carried out on three generations of one family who exhibited different venous occlusions and subsequent complications. RESULTS: Four members of the family, spanning three generations, suffered from complications of venous thrombosis. In the first generation a great uncle died of complications from a deep leg venous thrombosis. In the second generation, the mother underwent a venous branch thrombosis at the age of 41 with a protein S activity of 18%. Subsequently, a palsy of the N. abducens developed with multiple cerebral lesions (presumably post-thrombotic) in the MRI. Fluorescein angiography showed a typical picture of a venous branch occlusion which had been treated by laser. In the third generation, the 16-year-old daughter developed iliac venous thrombosis and a pulmonary embolism with a protein S activity of 0%. The fluorescein angiography showed distinctively engorged veins. A 28-year-old daughter, with a protein S activity of 16%, remained asymptomatic, although fluorescein angiography demonstrated engorged veins. Protein C activity and APC resistance of all family members were normal. The chromosomal analysis of the family members revealed no morphological aberrations. CONCLUSION:Protein S deficiency increases the risk of congenital thrombosis in young and middle-aged heterozygous individuals.