Severe prekallikrein deficiencies due to homozygous C529Y mutations.

Two consecutive severe prekallikrein deficiencies were investigated. The first was identified in a 63-year-old patient admitted for ischemic stroke. The second deficiency was identified in a 38-year-old patient admitted for a second-trimester pregnancy loss.

Prothrombin Suresnes: a case of homozygous F299V mutation responsible for hypodysprothrombinemia.

A patient with a severe prothrombin deficiency and a hemorrhagic diathesis was found to have positive cross-reactive material in plasma and a homozygous F299V mutation (F7V in the A chain). This mutation reinforces the previous conclusion that the A chain affects the geometry of the catalytic triad. Marked prolongation of the Taipan venom and Russell venom clotting times also demonstrated a defective activation mechanism and a defective interaction with factor Xa.