Does the determination of the Bb vitamin D receptor genotype identify psoriasis vulgaris patients responsive to topical tacalcitol?

LETTER TO THE EDITOR. Summary. In recent years, increasing evidence has demonstrated an association between several human pathologic conditions and the allelic variation in the 1,25-dihydroxyvitamin D receptor (VDR)… In both the Korean and Turkish population, a significant difference in VDR genotypes between normal controls and psoriasis vulgaris patients was demonstrated but so far no correlation with psoriasis clinical form was found, nor any role for the BsmI polymorphism analysis of the VDR gene in predicting clinical response to calcipotriol… Since VDR genotype distribution varies dramatically in different ethnic groups, we questioned whether in Italian Caucasian psoriasis patients the VDR polymorphism could be somehow related to clinical efficacy of topical tacalcitol, a potent vitamin D analogue… statistical analysis of PASI variation (variance analysis, significant for p < 0.05) displayed clearcut differences according VDR genotype. In particular, ‘‘Bb’’ patients could be regarded as better responders, whereas the ‘‘BB’’ group derived the poorest benefit from tacalcitol administration, and ‘‘bb’’ subjects had an intermediate improvement… although conducted on a small group, our study represents the first report of a ‘‘Bb’’ genotype-restricted responsiveness to vitamin D analogues in psoriasis vulgaris.