All are true about blood coagulation except?: (A) Intrinsic pathway can be activated in vitro., (B) Extrinsic pathway is activated by contact of plasma with negatively charged surfaces., (C) Calcium is very important for coagulation., (D) Factor X is a part of both intrinsic and extrinsic pathway.
Answer is D. • Ataxia telangiectasiais an autosomal recessive condition.
• Patients have increased sensitivity to x-ray-induced chromosome abnormalities.
• Characterized by an ataxic-dyskinetic syndrome beginning in early childhood, caused by neuronal degeneration predominantly in the cerebellum, the subsequent development of telangiectasias in the conjunctiva and skin, and immunodeficiency.
• The nuclei of cells in many organs (e.g., Schwann cells in dorsal root ganglia and peripheral nerves, endothelial cells as well as pituicytes) show a bizarre enlargement of the cell nucleus and are referred to as amphicytes.
• The lymph nodes, thymus, and gonads are hypoplastic.
• Clinical features include recurrent sinopulmonary infections and unsteadiness in walking.
• Increased risk of development of lymphoid malignant disease (T-cell leukemia and lymphoma)
All other options are autosomal dominant conditions.