Table 1.

Inborn errors of immunity (IEIs) caused by somatic mosaicism. Diseases here are those in which mosaic somatic variants lead to disease in patients. Not included are variants in asymptomatic individuals (for example gonadal mosaicism) or revertant mosaicism that in some cases can alleviate a disease phenotype. *Indicates disease was initially reported or predominantly mosaic

Disease phenotype		Gene	Chr	GOF or LOF mechanism	Type of mosaicism demonstrated	VAF in blood and/or cell type	References
Autoimmune lymphoproliferative syndrome (ALPS)		FAS	Chr10	LOF	Somatic	1–35% in blood (50% in DNTs)	[18–20]
RAS-associated autoimmune leukoproliferative disease (RALD)		KRAS*	Chr12	GOF	Somatic	NA	[21, 22]
		NRAS*	Chr1	GOF	Somatic	50%	[14, 23]
Autoinflammatory disorders	CAPS	NLRP3	Chr1	GOF	Somatic	2–45%	[14, 17, 24–30]
	NLRC4 GOF	NLRC4	Chr2	GOF	Somatic	30%	[31]
	TRAPS	TNFRSF1A	Chr12	GOF	Gonosomal	18–30%	[32]
	Blau syndrome	NOD2	Chr16	GOF	Somatic, gonosomal	7–13%	[33, 34]
	SAVI	TMEM173	Chr5	GOF	Somatic	NA	[35, 36]
	VEXAS	UBA1*	ChrX	LOF	Somatic	35–80% in blood 60–95% in myeloid cells	[37]
	JAK1 GOF	JAK1*	Chr1	GOF	Somatic	27%	[38]
Hypereosinophilic syndrome		STAT5B*	Chr17	GOF	Somatic	10–46%	[39]
Chronic Granulomatous disease		CYBB	ChrX	LOF	Somatic	NA	[40]
Inflammation, neutropenia bone marrow failure, and lymphoproliferation caused by TLR8 (INFLTR8)		TLR8*	ChrX	GOF	Somatic	8–26%	[41]

Abbreviations: CAPS, cryopyrin-associated autoinflammatory syndrome; CINCA, chronic infantile neurological, cutaneous, and articular syndrome; DNT, double-negative T cells; GOF, gain-of-function; LOF, loss-of-function; NA, not available; SAVI-STING, associated vasculopathy with onset in infancy; TRAPS, tumor-necrosis-factor-receptor-associated periodic syndrome; VAF, variant allele frequency; VEXAS, vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic