The accumulation of transformed primitive hematopoietic blast cells, which lose their ability of normal differentiation and proliferation.

A clonal expansion of myeloid blasts in the bone marrow, blood or other tissues. The classification of acute myeloid leukemias (AMLs) encompasses four major categories: 1) AML with recurrent genetic abnormalities; 2) AML with multilineage dysplasia; 3) Therapy-related AML; 4) AML not otherwise specified. The required bone marrow or peripheral blood blast percentage for the diagnosis of AML is 20% (WHO classification)

A cancer originating in lymphocytes and presenting as a solid tumor of lymhpoid cells.

Clonal hematopoietic stem cell disorders characterized by dysplasia (ineffective production) in one or more hematopoietic cell lineages, leading to anemia and cytopenia.

ALK-related neuroblastic tumor susceptibility is characterized by increased risk for neuroblastic tumors including neuroblastoma, ganglioneuroblastoma, and ganglioneuroma. Neuroblastoma is a more malignant tumor and ganglioneuroma a more benign tumor. Depending on the histologic findings, ganglioneuroblastoma can behave in a more aggressive fashion, like neuroblastoma, or in a benign fashion, like ganglioneuroma. Preliminary data from the ten reported families with ALK-related neuroblastic tumor susceptibility suggest an overall penetrance of approximately 57% with the risk for neuroblastic tumor development highest in infancy and decreasing by late childhood.

Epistaxis, or nosebleed, refers to a hemorrhage localized in the nose.

A reduction in the number of circulating thrombocytes.

Prolongation of the time taken for a standardized skin cut of fixed depth and length to stop bleeding.

An impairment in the rate and degree to which platelets aggregate after the addition of an agonist that stimulates platelet clumping. Platelet aggregation is measured using aggregometer to measure the optical density of platelet-rich plasma, whereby platelet aggregation causes the plasma to become more transparent.

A deviation from the normal contents of the platelet alpha granules, which normally contain adenosine triphosphate (ATP), adenosine diphosphate (ADP), serotonin, calcium, and pyrophosphate, which are secreted when platelets are activated.

A deviation from the normal contents of the platelet alpha granules, which normally contain hemostatic proteins such as fibrinogen, von Willebrand factor, and growth factors such as platelet-derived growth factor.

A deviation from the normal discoid platelet shape.

Abnormal response to arachidonic acid as manifested by reduced or lacking aggregation of platelets upon addition of arachidonic acid.

Abnormal response to collagen or collagen-mimetics as manifested by reduced or lacking aggregation of platelets upon addition collagen or collagen-mimetics.

Abnormal platelet response to ADP as manifested by reduced or lacking aggregation of platelets upon addition of ADP.

A purpuric lesion that is larger than 1 cm in diameter.

Petechiae are pinpoint-sized reddish/purple spots, resembling a rash, that appear just under the skin or a mucous membrane when capillaries have ruptured and some superficial bleeding into the skin has happened. This term refers to an abnormally increased susceptibility to developing petechiae.

Purpura (from Latin

An ecchymosis (bruise) refers to the skin discoloration caused by the escape of blood into the tissues from ruptured blood vessels. This term refers to an abnormally increased susceptibility to bruising. The corresponding phenotypic abnormality is generally elicited on medical history as a report of frequent ecchymoses or bruising without adequate trauma.