Summary
Abetalipoproteinaemia is a rare disorder of apolipoprotein B metabolism associated
with extremely low plasma concentrations of triglyce-ride. To discover whether the
general positive association between factor VII and triglyceride levels extends to
this condition, 5 patients were compared with 18 controls. All patients had a triglyceride
below 100 μmol/l. Plasma unesterified fatty acid concentration was normal. Although
factor IX activity was only slightly reduced (mean 88% standard) and factor IX antigen
was normal, mean activated factor VII in patients was strikingly reduced to 34% of
that in controls, a level similar to that found in haemophilia B. The patients’ mean
factor VII activity and factor VII antigen were also significantly reduced to 54%
and 63% of those in controls, respectively. Mean factor XI activity and tissue factor
pathway inhibitor activity were reduced in patients to 70% and 75% of control values
respectively, while factor XII, factor XI antigen, factor X, prothrombin and protein
C were normal.