Genetic risk factors for hypertrophic scar development.

Hypertrophic scars (HTSs) occur in 30 to 72% patients after thermal injury. Risk factors include skin color, female sex, young age, burn site, and burn severity. Recent correlations between genetic variations and clinical conditions suggest that single-nucleotide polymorphisms (SNPs) may be associated with HTS formation. The authors hypothesized that an SNP in the p27 gene (rs36228499) previously associated with decreased restenosis after coronary stenting would be associated with lower Vancouver Scar Scale (VSS) measurements and decreased itching. Patient and injury characteristics were collected from adults with thermal burns. VSS scores were calculated at 4 to 9 months after injury. Genotyping was performed using real-time polymerase chain reaction. Logistic regression was used to determine risk factors for HTS as measured by a VSS score >7. Three hundred subjects had a median age of 39 years (range, 18-91); 69% were male and median burn size was 7% TBSA (range, 0.25-80). Consistent with literature, the p27 variant SNP had an allele frequency of 40%, but was not associated with reduced HTS formation or lower itch scores in any genetic model. HTS formation was associated with American Indian/Alaskan Native race (odds ratio [OR], 12.2; P = .02), facial burns (OR, 9.4; P = .04), and burn size ≥20% TBSA (OR, 1.99; P = .03). Although the p27 SNP may protect against vascular fibroproliferation, the effect cannot be generalized to cutaneous scars. This study suggests that American Indian/Alaskan Native race, facial burns, and higher %TBSA are independent risk factors for HTS. The American Indian/Alaskan Native association suggests that there are potentially yet-to-be-identified genetic variants.