Gene detection in a family with monilethrix and treatment with 5% topical minoxidil.

Objective: To determine the causative gene mutation in a family with monilethrix and observe the therapeutic effect of 5% topical minoxidil.

Method: Clinical data from a family with monilethrix were collected. Peripheral blood samples were taken from the proband, the parents, and 100 unrelated healthy controls. Genomic DNA was extracted. The genetic variation sites were screened with exome sequencing and verified by Sanger sequencing. The proband was treated with 5% topical minoxidil (1 mL twice daily). Hair quality was examined by dermoscopy before and after treatment.

Results: The proband and her father have the heterozygous missense variant c.1204G > A (p.E402K) in exon 7 of the KRT86 gene. However, the mutation was not found in the mother and healthy controls. The proband was treated with 5% topical minoxidil. Hair density and hair shaft quality improved significantly after 6 months of treatment. No adverse events occurred during treatment.

Conclusion: This study shows that p.E402K is a mutation "hot spot" in patients with autosomal dominant monilethrix in China. Treatment with 5% topical minoxidil, is safe and effective.