Table 1.

Comparison of features seen in familial chilblain lupus,^4,7 Aicardi–Goutières syndrome¹ and Singleton–Merten syndrome⁶

	Familial chilblain lupus	Aicardi–Goutières syndrome	Singleton–Merten syndrome
Clinical features	Skin predominantly affected: acral chilblains (hands, feet, ears, nose). Arthralgia (articular deformities)	Major neurological involvement: progressive encephalopathy. Skin: acral chilblains (feet) (articular deformities). Glaucoma	Aortic calcification. Hypoplastic teeth.  Osteopenia. Psoriatic-type lesions.  Articular deformities. Glaucoma
Features on cerebral imaging	Not normally present	Intracranial calcification, white-matter disease, cerebral atrophy	Not reported previously
Inheritance mode	Autosomal dominant	Autosomal recessive (autosomal dominant)	Autosomal dominant
Genetic basis	TREX1, SAMHD1	TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, ADAR, IFIH1	IFIH1