Dyschromatosis universalis hereditaria with SASH1 mutation improved with picosecond laser treatment.

Dyschromatosis universalis hereditaria (DUH) is a rare autosomal dominant pigmentary skin disorder characterized by hypo- and hyperpigmented macules over the body. Although DUH is associated with mutations in ABCB6 and SASH1, other factors also contribute to the pathogenesis of DUH, as the lesions typically appear on the exposed areas of the skin and do not develop in all individuals with SASH1 mutations. Most reported cases of SASH1 mutations are in Chinese or Japanese patients who do not require treatment. Herein, we report a rare case of an 11-year-old boy presenting with an 8-year history of widespread brown spots. The lesions, which began on his face and spread to the trunk, limbs and oral mucosa, developed without photosensitivity. Whole-exome sequencing helped identify a heterozygous SASH1 mutation (c.1529G > A; exon13, NM_015278.5). Initial treatment with intense pulsed light did not result in any improvement; however, subsequent picosecond laser treatment led to significant improvement. Hence, this case highlights the phenotypic variability of DUH associated with SASH1 mutations and the potential role played by additional genetic or environmental factors in disease expression. Furthermore, picosecond laser treatment may be effective against hyperpigmented lesions, although further studies are required to assess its long-term efficacy and safety.