Legius syndrome: A case report.

Legius syndrome is a rare genetic disorder caused by heterozygous germ line loss-of-function SPRED1 mutation. In Japan, a family with Legius syndrome was first described in 2015 by Sakai et al. We described a first solitary case of Legius syndrome identified by next-generation sequencing in Japan. A 37-year-old woman presented with multiple café-au-lait macules and freckles but has no other features of neurofibromatosis type 1 (NF-1). Sequencing results showed the presence of a mutation in exon 2 of SPRED1 c.70C>T, resulting in the protein at position 24 (p.Arg24X). When a dermatological clinician sees an adult patient showing only pigmented lesions and no other specifically diagnostic features of NF-1, it is important to suspect the possibility of Legius syndrome.