Disease linked to JAK1 mutations
Definition
Rare immuno-inflammatory disease first described in 2017.
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Being a genetic disease caused by mutations of the JAK1 gene, the proposed Anglo-Saxon acronym is JAID for “JAK1 associated inflammatory disease”.
Epidemiology
To date, there are around twenty patients described in the literature (as of June 22, 2023).
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The disease is cosmopolitan; it affects both men and women and usually begins early in life.
Genetic
The disease has mainly been described in families with autosomal dominant transmission.
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A case of mutation brought to the state of somatic mosaic (that is to say that it does not concern all the cells of the organism) has been described.
Clinical
All patients present since childhood with severe atopic dermatitis with an elevation of polymorphonuclear eosinophils. Three quarters of patients also have asthma and food allergies.
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Some patients have joint pain, digestive disorders such as diarrhea, short stature or benign calcified tumors located in the envelopes of organs (serosa).
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On the blood test, we can see inflammation in the event of a flare-up of the disease, a drop in immunoglobulins, as well as markers of allergy such as an increase in polymorphonuclear basophils, immunoglobulins E and histamine.
Diagnostic
The diagnosis is based on a blood test showing the mutation of the JAK1 gene.
Evolution
It is not fully known because the disease is of recent description. The life expectancy of patients can reach that of the general population, but in the absence of treatment their quality of life can be significantly impaired due to skin involvement, allergic and digestive manifestations.
Some patients may develop severe asthma and lung infections.
Treatment
It has not yet been fully codified, but patients generally respond well to JAK inhibitors, particularly with regard to cutaneous, allergic and digestive manifestations.