Research of mutation of type II hair keratin gene in a pedigree of monilethrix

  • Weiling Sun, First Affiliated Hospital of Nanjing Medical University, China
  • Weixin Fan, First Affiliated Hospital of Nanjing Medical University, China
  • Jin Wu, First Affiliated Hospital of Nanjing Medical University, China
  • Yongli Lin, First Affiliated Hospital of Nanjing Medical University, China
  • Wenrong Xu, First Affiliated Hospital of Nanjing Medical University, China
  • Zhongming Li, First Affiliated Hospital of Nanjing Medical University, China

Objective: To investigate the mutation of type II human basic hair keratin (hHb) gene in a family of monilethrix. Methods: The affected hair shaft structure was observed by scanning electron microscope. Informed consent for the study was obtained from all the family members and fifties healthy people. Their peripheral blood samples were drawn for their genomic DNA. Exon 1 and exon 7 of hHb1, hHb3 and hHb6 were amplified by polymerase chain reaction (PCR). All PCR products were sequenced directly using ABI3730 automated sequencer. These sequences were compared with those in the internet with BLAST software. Results: The affected hair showed periodic hair thinning in the scanning electron microscope. There was hair cuticle and many longitudinal ridges and sulcuses in the thinning hair. The unregulated hair cuticle existed in many members of the family but one who had fewer cortexes and no medullary substance. A series of specific PCR products were obtained from all specimens. 1289 G/A (R430Q) was identified in exon 7 of hHb6 gene from these family members, which didn’t exist in the 50 healthy people. The exon 1 and exon 7 of hHb1, hHb3 and the exon 1 of hHb6 were detected no mutation. Conclusion: The missense mutation of R430Q may be important in the cause of the disease in this pedigree.