Erythema dyschronicum perstans with both a macular lesion and a linear lesion following the lines of Blaschko

Abstract

extracellular ligand-binding domain, the transmembrane domain and only the proximal portion of the intracellular TK domain. The nucleotide change was not detected in the healthy individuals from the family and 100 unrelated controls, making it highly likely that this mutation is pathogenic and not a polymorphism.To date, 62 mutations and one pericentric chromosomal inversion have been reported in human piebaldism. 2 These genetic studies indicated that clinical manifestations and phenotypic severity of piebaldism clearly correlate with the site and the type of mutation within the KIT gene. By now, six KIT frame-shift mutations within the intracellular TK domain have been described in seven families with piebaldism. [3][4][5] As with the mutation reported here, all these known mutations were associated with variable piebaldism phenotypes. This is consistent with the view that frame-shift mutations located in the intracellular TK domain caused variable piebaldism phenotypes among members of individual families, because of the combination of haploinsufficiency and dominant-negative effect, which reduced the KIT function by 50-75%. 5 Functional analysis in vitro and in vivo of this mutation would need to be performed before this could be ascertained. It was also possible that other modifying genes such as SLUG (snail gene family of zinc-finger transcription factors) and MC1R encoding the melanocortin-1 receptor for melanocortins could be involved with the variable phenotype observed here. 2 ACKNOWLEDGMENTSWe are grateful to the patients and family members for their participation in our study. REFERENCES1 Spritz RA, Holmes SA, Itin P, Kuster W. Novel mutations of the KIT (mast/stem cell growth factor receptor) proto-oncogene in human piebaldism.Dear Editor, Erythema dyschromicum perstans (EDP) (ashy dermatosis) is an idiopathic acquired dermal melanosis characterized by asymptomatic, ash-colored (slate-gray to blue-brown) macules. 1,2 Until now, two east Asian patients with EDP following the lines of Blaschko 3,4 and a Japanese patient with EDP showing linear and macular involvement 5 have been described in the English-language published work. We describe a Japanese case of EDP with both a macular lesion and a linear lesion following the lines of Blaschko. A 31-year-old Japanese woman was referred to us in June 2012 with asymptomatic pigmentary anomalies on the right chest and the right back. The patient initially noticed the erup-tion with no preceding inflammation in January 2012. The eruption gradually spread in a linear distribution accompanied by the occurrence of a pigmented macule. The family members had no pigmentary anomalies. Physical examination revealed an asymptomatic ash-colored hyperpigmented linear lesion following the lines of Blaschko (arrow) surrounded partly by erythematous borders (dotted fine arrow), and an asymptomatic ash-colored hyperpigmented macule (fine arrow) adjacent to the hyperpigmented linear macule on the right chest and the right lateral back (Fig. 1a).A biopsy specimen from the hype...

Diagnosing congenital hypochromic patches

“…Piebaldism is a rare, autosomal-dominant disorder, with implication on melanocyte development and migration, resulting in patchy depigmentation of hair and skin. Most cases are associated with mutations in the tyrosine kinase domain of the KIT proto-oncogene 1 2. The primary challenge in these cases is the differential diagnosis with Waarderburg syndrome (WS), a disorder that presents a similar phenotype of depigmentation of hair and skin associated with neurosensory alterations 2…”

“…Most cases are associated with mutations in the tyrosine kinase domain of the KIT proto-oncogene 1 2. The primary challenge in these cases is the differential diagnosis with Waarderburg syndrome (WS), a disorder that presents a similar phenotype of depigmentation of hair and skin associated with neurosensory alterations 2…”

“…The ‘white forelock’, a triangular or diamond-shaped, midline area of white hair on the frontal scalp, is the most distinctive clinical manifestation of piebaldism and is present in the vast majority of affected individuals, even though it can also occur in WS 1 2…”