Gain-of-Function Mutation of KIT Ligand on Melanin Synthesis Causes Familial Progressive Hyperpigmentation

Zhi Qiang Wang, Lizhen Si, Quan Tang, Debao Lin, Zhangjie Fu, Jing Zhang, Bin Cui, Yufei Zhu, Xianghua Kong, Min Deng, Yu Xia, Heng Xu, Weidong Le, Landian Hu, Xiangyin Kong

Research output: Contribution to journalArticle

45 Scopus citations

Abstract

Familial progressive hyperpigmentation (FPH) is an autosomal-dominantly inherited disorder characterized by hyperpigmented patches in the skin, present in early infancy and increasing in size and number with age. The genetic basis for FPH remains unknown. In this study, a six-generation Chinese family with FPH was subjected to a genome-wide scan for linkage analysis. Two-point linkage analysis mapped the locus for FPH at chromosome 12q21.31-q23.1, with a maximum two-point LOD score of 4.35 (Ø = 0.00) at D12S81. Haplotype analysis confined the locus within an interval of 9.09 cM, flanked by the markers D12S1667 and D12S2081. Mutation profiling of positional candidate genes detected a heterozygous transversion (c. 107A→G) in exon 2 of the KIT ligand (KITLG) gene, predicted to result in the substitution of a serine residue for an asparagine residue at codon 36 (p.N→S). This mutant "G" allele cosegregated perfectly with affected, but not with unaffected, members of the FPH family. Function analysis of the soluble form of sKITLG revealed that mutant sKITLGN36S increased the content of the melanin by 109% compared with the wild-type sKITLG in human A375 melanoma cells. Consistent with this result, the tyrosinase activity was significantly increased by mutant sKITLGN36S compared to wild-type control. To our knowledge, these data provided the first genetic evidence that the FPH disease is caused by the KITLGN36S mutation, which has a gain-of-function effect on the melanin synthesis and opens a new avenue for exploration of the genetic mechanism of FPH.

Original languageEnglish (US)
Pages (from-to)672-677
Number of pages6
JournalAmerican Journal of Human Genetics
Volume84
Issue number5
DOIs
StatePublished - May 15 2009

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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