Both my sister and I have had ITP. She had it in 1982 and I was diagnosed in 1998. I think it was coincidence for us. ITP itself is not hereditary and it is uncommon for two family members to have ITP. Sometimes there is a hereditary disposition toward autoimmune disorders and two family members can end up with it. That is rare. There are however, hereditary types of ITP.
Here is the info for familial ITP. It might be worth looking into because the treatments can be different for these disorders. I've seen a few people over the years who were told it was 'just ITP' and then found out years later that it was more than that.
Inherited Thrombocytopenia
Inherited thrombocytopenia may be caused by an inherited defect in platelet production or a process that influences platelet destruction. There are many forms of inherited thrombocytopenia, all of them rare. This means that physicians, even hematologists, will frequently mistake them for something else. Some of the more common examples are listed below.
MYH9 Related Diseases
(includes May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome or Epstein syndrome)
These diseases are grouped because they are all caused by mutations of the MYH9 gene. May-Hegglin anomaly, the most familiar, is an autosomal dominant condition in which either affected parent can pass the trait to their children, with a 50% likelihood of each child being thrombocytopenic. It is characterized by abnormally large platelets (that are frequently undercounted by automated machines), mild to moderate bruising, and potential for hearing and kidney problems.
www.registromyh9.org/English_version/
www.ncbi.nlm.nih.gov/pubmed/21542825
www.ncbi.nlm.nih.gov/pubmed/20844233
Wiskott-Aldrich Syndrome (WAS)
Wiskott-Aldrich Syndrome is an X-linked disorder, affecting only males (females can be carriers but are unaffected). Platelets are very small and are often accompanied by immunodeficiency and eczema.
www.emedicine.com/med/topic1162.htm#section~introduction
www.ncbi.nlm.nih.gov/pubmed/21659547
www.scripps.edu/bcmd/pdfarea/issue_15_99/bcmd0247.pdf
Congenital Amegakaryocytic Thrombocytopenia (CAMT)
CAMT is a recessive condition in which both parents are carriers but neither has low platelets. One fourth of their children (on average) will be affected with severe thrombocytopenia and absence of megakaryocytes in the bone marrow. Because of the severity of this disease, it is usually recognized shortly after birth. This disease is caused by mutations that affect the major platelet growth factor receptor and usually worsens over time until no cells are made in the bone marrow (aplastic anemia).
www.ncbi.nlm.nih.gov/pubmed/11133753
www.ncbi.nlm.nih.gov/pubmed/21151552
Autoimmune Lymphoproliferative Syndrome (ALPS)
ALPS is both inherited and immune-mediated and can be noticed in children as well as adults. People with ALPS have a large numbers of white blood cells (lymphocytes) and low numbers of red blood cells and platelets.
www.niaid.nih.gov/topics/alps/Pages/default.aspx
www.ncbi.nlm.nih.gov/pubmed/21626105
www.ncbi.nlm.nih.gov/pubmed/21447005
Gray Platelet Syndrome
"When a blood vessel is injured (like a cut on a finger), platelets release the proteins stored in their sacs to help form a blood clot. Patients with GPS bleed longer than other people because their platelets lack some of these protein-carrying sacs. Platelets without sacs look pale gray under the microscope rather than pink, giving the syndrome its name. Except for rare patients with severe hemorrhage, the bleeding tendency in GPS is usually mild to moderate, with patients experiencing easy bruising, nosebleeds, and, in women, excessive menstrual bleeding." 1
(1)
www.clinicaltrials.gov/ct/show/NCT00069680?order=1
www.ncbi.nlm.nih.gov/pubmed/21765413
Bernard-Soulier Syndrome
Bernard-Soulier Syndrome is an autosomal recessive inherited disease (both parents must carry the genetic trait) caused by a defect in platelet glycoprotein complex 1b-IX-V. In addition to thrombocytopenia, people with Bernard-Soulier Syndrome have very large platelets and platelet function defects that prompt much more bleeding at a particular platelet count than people with ITP.
www.ncbi.nlm.nih.gov/pubmed/21357716
www.medicinenet.com/bernard-soulier_disease/article.htm
emedicine.medscape.com/article/954877-overview
Von Willebrand Disease Type 2B
Von Willebrand Factor is a protein in the blood needed for normal clotting. Von Willebrand Disease is caused by a defect in that protein, leading to abnormal bleeding. In the Type 2b variety of this disease, platelets stick to the abnormal von Willebrand factor rather than to each other. This action forms platelet clumps and causes thrombocytopenia. Type 2b can be inherited from either parent and affects males and females equally.
www.hemophilia.org/bdi/bdi_types3.htm
bloodjournal.hematologylibrary.org/content/108/8/2498.full
ANKRD26-related thrombocytopenia
Thrombocytopenia cases caused by a mutation in the ANKR26 gene are more prevalent than previously thought, researchers reported in 2011. This mutation, transmitted by one parent, results in fewer platelets being released from the bone marrow.
www.ncbi.nlm.nih.gov/pubmed/21467542
www.ncbi.nlm.nih.gov/pubmed/21211618
Common Variable Immune Deficiency+
This genetic disorder is characterized by a low level of protective antibodies, recurrent infections, and possibly a large spleen. About 25% of people with this type of immune deficiency develop ITP. Primary immunodeficiencies (PID) can also present with low platelets.
primaryimmune.org/about-primary-immunodeficiency-diseases/types-of-pidd/common-variable-immune-deficiency
www.ncbi.nlm.nih.gov/pubmed/15232313
www.ncbi.nlm.nih.gov/pubmed/20008192
Mutations in Filamin-A
People with mutations in the X-linked FLNa gene have large platelets and possibly hemorrhage, abnormal clotting, as well as low platelets. This can be associated with periventricular nodular heterotopia (FLNA-PVNH), a disease characterized by the migration of grey matter to places outside of the cortex in the brain.
www.ncbi.nlm.nih.gov/pubmed/21960593
PVNH Support and Awareness (patient support group)
Mutations in GATA-1
The GATA1 gene on the X-chromosome regulates red cell and platelet development, so people with a mutation in GATA1 have both low red cells and low platelets. Because GATA1 is on the X-chromosome, boys- who only have a single X-chromosome- are affected more often than girls, a pattern referred to as X-linked inheritance. Platelets in boys who have inherited a mutant GATA1 are typically large and have few of the granules found in normal platelets.
www.ncbi.nlm.nih.gov/pubmed/18930124
For more information about inherited thrombocytopenia see "Inherited thrombocytopenia: when a low platelet count does not mean ITP." by Dr. Jonathan Drachman.
Substance-Induced Thrombocytopenia
pdsa.org/resources/other-platelet-disorders.html#inherited-thrombocytopenia
