Janus kinase 3 deficiency | |
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Other names | JAK3 deficiency |
JAK3 (Janus kinase 3) deficiency is a dysfunction in cytokine receptor signalling and their production of cytokines.
JAK3 is a tyrosine protein kinase, an enzyme that is encoded by the JAK3 gene. It is a kinase that is activated only by cytokines whose receptors contain the common gamma chain subunit (IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21). JAK3 is involved in initiating signalling for the cytokine receptors because they itself lack enzymatic activity. Once activated, the JAK kinase phosphorylates specific tyrosine residues on the cytokine receptor subunits which then activate STAT transcription factors. JAK3 helps to regulate differentiation and maturation of B cells, T cells and NK cells.
Mutations in the JAK3 gene can cause dysfunction of the kinase leading to autosomal severe combined immunodeficiency (SCID) disease [1] or on the contrary, the activation of mutated JAK3 can lead to development of leukemia. The JAK3 tyrosine kinase is mutated in 10% to 16% of T-cell acute lymphoblastic leukemia (T-ALL) cases. [2]
Patients with JAK3-deficiency lack the necessary immune cells, meaning that they do not have T cells and NK cells but have normal level but poorly functioning B cells. The necessary immune cells have resistance and ability to fight off certain bacteria, viruses, and fungi. The patients are then prone to repeated and persistent infections that can be very serious or life-threatening. [3]
Affected infants typically develop chronic diarrhea, a fungal infection in the mouth called oral thrush (candidiasis), pneumonia, and skin rashes. Constant illness also causes slower development of the affected individuals. Without treatment, people with JAK3-deficient SCID usually live only into early childhood. [3]
In suspection of a genetic mutation after physical examination, checking personal and family medical history and laboratory tests (measuring levels of certain substances or biochemical test of the blood and urine) can be used genetic testing as certain diagnosis. Genetic testing identifies changes in chromosomes, genes, or proteins. However, some conditions do not have a specific genetic test; either the genetic cause of the condition is unknown or a test has not yet been developed. In these cases, a combination of the approaches listed above may be used to make a diagnosis.
The treatment for JAK3 deficiency is allogeneic hematopoietic stem cell transplantation, which has been demonstrated to be life-saving for affected patients. [4]
Another option is gene therapy that has the potential to become an alternative treatment for JAK3 deficiency. Because of the clinical and biochemical similarities between JAK3 deficiency and X-linked severe combined immunodeficiency, genetic correction and engraftment of autologous hematopoietic stem cells can presume restoring of immunity in JAK3-deficient patients.[ citation needed ]
Severe combined immunodeficiency (SCID), also known as Swiss-type agammaglobulinemia, is a rare genetic disorder characterized by the disturbed development of functional T cells and B cells caused by numerous genetic mutations that result in differing clinical presentations. SCID involves defective antibody response due to either direct involvement with B lymphocytes or through improper B lymphocyte activation due to non-functional T-helper cells. Consequently, both "arms" of the adaptive immune system are impaired due to a defect in one of several possible genes. SCID is the most severe form of primary immunodeficiencies, and there are now at least nine different known genes in which mutations lead to a form of SCID. It is also known as the bubble boy disease and bubble baby disease because its victims are extremely vulnerable to infectious diseases and some of them, such as David Vetter, have become famous for living in a sterile environment. SCID is the result of an immune system so highly compromised that it is considered almost absent.
Adenosine deaminase deficiency is a metabolic disorder that causes immunodeficiency. It is caused by mutations in the ADA gene. It accounts for about 10–20% of all cases of autosomal recessive forms of severe combined immunodeficiency (SCID) after excluding disorders related to inbreeding.
The JAK-STAT signaling pathway is a chain of interactions between proteins in a cell, and is involved in processes such as immunity, cell division, cell death, and tumour formation. The pathway communicates information from chemical signals outside of a cell to the cell nucleus, resulting in the activation of genes through the process of transcription. There are three key parts of JAK-STAT signalling: Janus kinases (JAKs), signal transducer and activator of transcription proteins (STATs), and receptors. Disrupted JAK-STAT signalling may lead to a variety of diseases, such as skin conditions, cancers, and disorders affecting the immune system.
Omenn syndrome is an autosomal recessive severe combined immunodeficiency. It is associated with hypomorphic missense mutations in immunologically relevant genes of T-cells such as recombination activating genes, Interleukin-7 receptor-α (IL7Rα), DCLRE1C-Artemis, RMRP-CHH, DNA-Ligase IV, common gamma chain, WHN-FOXN1, ZAP-70 and complete DiGeorge syndrome. It is fatal without treatment.
X-linked agammaglobulinemia (XLA) is a rare genetic disorder discovered in 1952 that affects the body's ability to fight infection. As the form of agammaglobulinemia that is X-linked, it is much more common in males. In people with XLA, the white blood cell formation process does not generate mature B cells, which manifests as a complete or near-complete lack of proteins called gamma globulins, including antibodies, in their bloodstream. B cells are part of the immune system and normally manufacture antibodies, which defend the body from infections by sustaining a humoral immunity response. Patients with untreated XLA are prone to develop serious and even fatal infections. A mutation occurs at the Bruton's tyrosine kinase (Btk) gene that leads to a severe block in B cell development and a reduced immunoglobulin production in the serum. Btk is particularly responsible for mediating B cell development and maturation through a signaling effect on the B cell receptor BCR. Patients typically present in early childhood with recurrent infections, in particular with extracellular, encapsulated bacteria. XLA is deemed to have a relatively low incidence of disease, with an occurrence rate of approximately 1 in 200,000 live births and a frequency of about 1 in 100,000 male newborns. It has no ethnic predisposition. XLA is treated by infusion of human antibody. Treatment with pooled gamma globulin cannot restore a functional population of B cells, but it is sufficient to reduce the severity and number of infections due to the passive immunity granted by the exogenous antibodies.
ZAP70 deficiency, or ZAP70 deficient SCID, is a rare autosomal recessive form of severe combined immunodeficiency (SCID) resulting in a lack of CD8+ T cells. People with this disease lack the capability to fight infections, and it is fatal if untreated.
X-linked severe combined immunodeficiency (X-SCID) is an immunodeficiency disorder in which the body produces very few T cells and NK cells.
Hyper IgM syndrome is a rare primary immune deficiency disorders characterized by low or absent levels of serum IgG, IgA, IgE and normal or increased levels of serum IgM.
The interferon-gamma receptor (IFNGR) protein complex is the heterodimer of two chains: IFNGR1 and IFNGR2. It binds interferon-γ, the sole member of interferon type II.
Signal transducer and activator of transcription 1 (STAT1) is a transcription factor which in humans is encoded by the STAT1 gene. It is a member of the STAT protein family.
Cluster of differentiation antigen 135 (CD135) also known as fms like tyrosine kinase 3, receptor-type tyrosine-protein kinase FLT3, or fetal liver kinase-2 (Flk2) is a protein that in humans is encoded by the FLT3 gene. FLT3 is a cytokine receptor which belongs to the receptor tyrosine kinase class III. CD135 is the receptor for the cytokine Flt3 ligand (FLT3L).
Non-receptor tyrosine-protein kinase TYK2 is an enzyme that in humans is encoded by the TYK2 gene.
Tyrosine-protein kinase JAK3 is a tyrosine kinase enzyme that in humans is encoded by the JAK3 gene.
The severe combined immunodeficiency (SCID) is a severe immunodeficiency genetic disorder that is characterized by the complete inability of the adaptive immune system to mount, coordinate, and sustain an appropriate immune response, usually due to absent or atypical T and B lymphocytes. In humans, SCID is colloquially known as "bubble boy" disease, as victims may require complete clinical isolation to prevent lethal infection from environmental microbes.
Insulin-like 3 is a protein that in humans is encoded by the INSL3 gene.
Tyrosine-protein kinase Tec is a tyrosine kinase that in humans is encoded by the TEC gene. Tec kinase is expressed in hematopoietic, liver, and kidney cells and plays an important role in T-helper cell processes. Tec kinase is the name-giving member of the Tec kinase family, a family of non-receptor protein-tyrosine kinases.
A NOG (NOD/Shi-scid/IL-2Rγnull) mouse is a new generation of severely immunodeficient mouse, developed by Central Institute for Experimental Animals (CIEA) in 2000. The NOG mouse accepts heterologous cells much more easily compared with any other type of immunodeficient rodent models, such as nude mouse and NOD/scid mouse. Thus, the mouse can be the best model as a highly efficient recipient of human cells to engraft, proliferate and differentiate. This unique feature offers a great opportunity for enhancing therapy researches of cancer, leukemia, visceral diseases, AIDS, and other human diseases. It also provides applications for cancer, infection, regeneration, and hematology researches.
The NSG mouse is a brand of immunodeficient laboratory mice, developed and marketed by Jackson Laboratory, which carries the strain NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ. NSG branded mice are among the most immunodeficient described to date. NSG branded mice lack mature T cells, B cells, and natural killer (NK) cells. NSG branded mice are also deficient in multiple cytokine signaling pathways, and they have many defects in innate immunity. The compound immunodeficiencies in NSG branded mice permit the engraftment of a wide range of primary human cells, and enable sophisticated modeling of many areas of human biology and disease. NSG branded mice were developed in the laboratory of Dr. Leonard Shultz at Jackson Laboratory, which owns the NSG trade mark.
Interleukin-7 receptor subunit alpha (IL7R-α) also known as CD127 is a protein that in humans is encoded by the IL7R gene.
Reticular dysgenesis (RD) is a rare, inherited autosomal recessive disease that results in immunodeficiency. Individuals with RD have mutations in both copies of the AK2 gene. Mutations in this gene lead to absence of AK2 protein. AK2 protein allows hematopoietic stem cells to differentiate and proliferate. Hematopoietic stem cells give rise to blood cells.