Dysregulatory syndromes: the role of signal transducers and activators of transcription.

PURPOSE OF REVIEW: A comparative description of dysregulatory syndromes with mutations in signal transducer and activator of transcription (STAT) genes.

RECENT FINDINGS: STAT 1, 3 and 5b loss of function (LOF) and gain of function (GOF) mutations are a heterogeneous group of genetic disorders that range from immunodeficiency (ID) to autoimmune disease (AID), depending on the underlying signalling pathway defect. Between them, there are clear overlapping and differences in clinical presentation and laboratory findings.

SUMMARY: Dysregulatory syndromes due to LOF and GOF mutations in STAT1, 3 and 5b are a particular group of primary immunodeficiencies (PIDs) in which AID may be the predominant finding in addition to infections susceptibility. STAT1 GOF mutations were described as the major cause of chronic mucocutaneous candidiasis, while activating STAT3 mutations result in early-onset multiorgan autoimmunity and ID. Human STAT5b deficiency is a rare disease that also involves ID and severe growth failure. In recent years, the identification of the genes involved in these disorders allowed to differentiate these overlapping syndromes in order to choose the most effective therapeutic options.