ABSTRACT
Objective To report a pedigree with X?linked dominant protoporphyria(XLDPP), and to detect 5?aminolevulinic acid synthetase 2(ALAS2)gene mutations in this pedigree. Methods A clinical investigation was performed in a pedigree with XLDPP, and relevant data were collected from family members. A next?generation sequencing method was applied to screen possible mutation sites, and Sanger sequencing was performed to determine pathogenic gene mutations. Dermoscopy was conducted to observe skin lesions in the patients with XLDPP, and the Fotofinder system and very high frequency (VHF) ultrasound system were utilized to assess the severity of photodamage. Liver and gallbladder ultrasonography as well as blood examination were performed for all the family members. Results A deletion mutation, c.1706?1709ΔAGTG, was detected in the ALAS2 gene on the X chromosomes of all the patients in this family, which led to replacement or loss of 19-20 C?terminal residues through transcriptional frameshifting, and eventually caused an increase in ALAS2 activity. In the patients with XLDPP, skin photodamage was relatively severe;protoporphyrin?induced hepatobiliary damage was observed and aggravated with age;anemia and iron deficiency occurred sometimes. Conclusion The deletion mutation c.1706?1709ΔAGTG of the ALAS2 gene may be the underlying cause of XLDPP in this pedigree.