Homozygous or compound heterozygous qualitative antithrombin III deficiency.
A male patient of 24 years who had experienced thrombotic episodes since the age of 15 displayed an unusually low antithrombin III (AT III) activity measured as heparin cofactor (13% of the normal), while a similarly decreased value (16% of normal) was found in a 26 year old brother who had suffered from thrombotic events since the age of 12 years. AT III heparin cofactor activities were close to 50% of normal in the father, mother, another brother and a sister, none of whom had experienced thrombotic episodes. Since all available members of the family, including the patient, displayed near normal AT III antigen levels (73-85%) normal total progressive antithrombin activities (92-110%) as assessed by the thrombin agarose diffusion technique and normal total progressive anti-Xa activities, the propositus and his brother could be considered to be homozygotes or compound heterozygotes for a qualitative familial AT III deficiency probably caused by an abnormality of the heparin binding site. Molecular techniques would be required to elucidate the precise mutation giving rise to the deficiency.
Clinica Medicala I, Cluj-Napoca, Romania.
M
M
Cucuianu
S
S
Blaga
S
S
Pop
D
D
Olinic
N
N
Olinic
D
D
Colhon
A
A
Cristea
D000293:Adolescent; D000328:Adult; D000990:Antithrombin III / Q000235:genetics / Q000378:metabolism; D020152:Antithrombin III Deficiency; D001665:Binding Sites; D065427:Factor Xa Inhibitors; D005260:Female; D005838:Genotype; D006493:Heparin / Q000378:metabolism; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree
D065427:Factor Xa Inhibitors; D000990:Antithrombin III; D006493:Heparin