Image via Wikipedia

-remember that they are non nucleated vesicles that arise from megakaryocytes.

-mutation in many genes can interfere with the function of the platelets

-there have been more than 50 platelet plasma membrane proteins that have been recognized. And there are this many genes in which mutations can interrupt function. These 50 have been assigned into 5 gene families.


-huge multiplicity of genes and function can lead to many mutations. Given that platelets are so central in hemostasis there is a lot of potential for bleeding disorders that revolve around the mechanisms in disabling platelet function.

-platelet dysfunction can be described in several ways


-Bernard-Souliar Syndrome: Thrombocytopenia, in which thrombocytes are low in number.


-Glanzmann Thrombasthenia- platelet fail to aggregate in their customary manner. Clot will stay loose and fail to harden. This is a rare disorder, and autosomal recessive.

-Platelet storage granule defects

-Hermanzkie-Pudlak Syndrome: This syndrome shows that you can have other system elements in the phenotype not just bleeding. There is severe albinism in addition to problem with bleeding. There is an accumulation in reticulo-endothelial cells in bone marrow and other tissues of a serous like material.

-Chediak-Higashi Syndrome- multi-system effects. There is partial albinism, you will see large granules cytologically in the platelets. You will also see large granules in leukocytes. This is therefore an immune dysfunction and a bleeding dysfunction. There are serous like deposits responsible for this.

-abnormality in platelet size and number

-T.A.R. Syndrome (Thromboyctopenia-Absence of Radius) involves anatomic formation and thrombocytopenia. If newborn baby present with an absence of the radius bone or thumb in one arm, you will want to do a platelet count. You will find that there may also be thrombocytopenia. X-linked inherited defect, seen mostly in baby boys. The thrombocytopenia that you see is hypomegakaryotciticà the karyocytes look big, but the platelets (or thrombocytes) are not being derived from them in sufficient numbers.

-Whiskott-Aldrich Syndrome: a signal transduction defect, the cytoplasmic membrane receptor or an intracellular cascade protein is defective. This will lead to an insufficiency in platelet size. They are unusually small. There is a sever deficiency in number of platelets as well. There is a severe immune defect, and eczema (skin disorder).

Related articles

• Monitoring patients for HIT (doctorrw.blogspot.com)

Image via Wikipedia

-Diverse Immunoglobulin gene deficiencies exist.

-complete deficiency in immunoglobulins X-Linked agammaglobulinemia. Absence of gamma-globulins

-specific Ig chain deficiencies, you will see a selective set of susceptibility to a certain set of microorganisms.

-X-linked-hyperimmunoglibulin M, an excess of IgM production. Seen mostly in males.

-Ig Sub-class deficiencies- remember the gamma globulins have 3 of 4 subclasses. It is clinically not difficult to recognize that a child who comes repeatedly for inner ear infection with the same microorganism, you should look into it being a selective Ig deficiency. Inner ear infection has proven to be a genetic susceptibility.

-T Cell and B cell numbers can be modified or impaired as a result of mutation. There will be a diverse set of phenotypes.

Image via Wikipedia

-T-cell receptor signal transduction deficiency.

-failure in antigen presentation by the T cells Bear lymphocyte syndrome

-mutations in metabolic genes ie: Adenosine deaminase (imp enzyme in DNA metabolism) can have a consequence of impaired B-Cell function.