Dyschromatosis Universalis Hereditaria
Characteristic findings of DUH are diffuse symmetrically distributed hypopigmented macules mixed with hyperpigmentation, including on the face (Figure 3). Most patients with DUH show skin lesions on the trunk or extremities in infancy or early childhood; the lesions usually stop spreading before adolescence.[26–29] Histologically, there is an increase or decrease of melanin pigmentation in the basal cells of hyperpigmented lesions or hypopigmented macules, respectively, and pigmentary incontinence can occasionally be observed by light microscopy. Other ultrastructural investigations in a patient with DUH with autosomal recessive inheritance revealed that melanocyte numbers were not affected; however, the number of melanosomes per melanocyte was significantly reduced in hypopigmented epidermis (both melanocytes and keratinocytes) compared with hyperpigmented lesions, suggesting that melanosome synthesis and maturation are affected in DUH.
Clinical features of dyschromatosis universalis hereditaria in a patient with a ABCB6 mutation: hyper- and hypopigmented macules in a generalized distribution. (Picture kindly provided by Dr Hong Liu.)
DUH, like DDD, is a clinically and genetically heterogeneous disorder. Most patients with DUH show an autosomal dominant mode of inheritance, whereas some pedigrees of DUH present with an autosomal recessive inheritance pattern.[32,33] Two candidate loci were initially reported to be responsible for DUH: 6q24·2-q25·2 and 12q21-q23.[32,34] In 2013, Zhang et al. performed next-generation sequencing and revealed the pathogenic mutations to be in the ATP-binding cassette subfamily B, member 6 (ABCB6) gene in patients with typical DUH. Soon afterwards, Liu et al. also provided evidence that ABCB6 is involved in DUH and noticed the coexistence of pigmentation and ocular abnormalities in their patients with DUH. This result supports the opinion that the ABCB6 protein has an important effect on both pigmentation and ocular development.[28,35]
Xeroderma pigmentosum (XP) resembles DUH clinically in its presentation of freckle-like hyper- and hypopigmentated spots (Figure 4). However, patients with DUH usually show only pigmentary phenotypes with no systemic involvement, whereas patients with XP can present with atrophy, xerosis, and many complications including growth and mental retardation, ocular abnormalities, sunlight sensitivity and skin cancers.[36,37]
Clinical features of xeroderma pigmentosum in a patient whose presentation clinically resembles dyschromatosis universalis hereditaria in manifesting freckle-like spots, but is distinguished by atrophy, xerosis and telangiectasia.
Currently, no effective treatment for pigmented and depigmented lesions in DUH has been established. Dermatologists should be particularly aware of the risk of ocular abnormalities.
The British Journal of Dermatology. 2017;177(4):945-959. © 2017 Blackwell Publishing