Genetic susceptibility to keloid scarring: SMAD gene SNP frequencies in Afro-Caribbeans

Keloid disease (KD) is a fibroproliferative dermal tumour of unknown aetiology. The increased familial clustering in KD, its increased prevalence in certain races and increased concordance in identical twins suggest a strong genetic predisposition to keloid formation. The highest incidence of keloids is found in the black population, where it has been estimated around 4-6% and up to 16% in random samples of black Africans. SMAD genes 3, 6 and 7 were investigated as candidate genes in Jamaican patients with keloid scars (n = 183) and a matched control population (n = 121) because of their previously reported involvement in fibrotic disorders and to determine if they were associated with keloid disease susceptibility. Thirty Five SNPs across these genes were genotyped using Time-of-Flight Mass Spectrometry (MALDI-TOF MS) and iPLEX assay. Linkage disequilibrium (LD) was established between several of the SNPs investigated. In the Jamaican population, the SMAD SNPs investigated for this study were not strongly associated with increased risk of developing KD. Identification of genetic markers in candidate genes such as the SMAD family may be of significant importance in diagnosis, prognosis and development of new therapies in the management of keloid scarring.