1,25-Dihydroxyvitamin D is the biologically active form of
vitamin D for the treatment of skin eruptions in patients with
psoriasis. 1,25-(OH)(2)D(3) elicits its action on skin eruptions through the
vitamin D receptor (VDR). Allelic frequencies of VDR were studied in 86 normal subjects and 50 patients with
psoriasis. Genomic
DNA was extracted from peripheral blood leukocytes and the VDR gene was amplified using a heminested polymerase chain reaction (PCR). The products were digested with respective restriction
enzymes ApaI, TaqI and BsmI. The restriction fragment length polymorphisms (RFLP) were coded as Aa, Tt or Bb. The frequencies of
ApaI, BsmI and TaqI RFLP genotypes in
psoriasis patients showed no significant differences compared with normal controls. The frequency of the AA genotype was significantly higher in
pustulosis palmaris et plantaris patients than in
psoriasis vulgaris patients ( P<0.05), and in
psoriasis vulgaris patients than in
psoriasis pustulosa patients ( P<0.01). In patients with
psoriasis, the levels of serum
alanine 2-oxoglutarate aminotransferase (ALT) were significantly higher in patients with the AA genotype (54.0+/-22.0 IU/l, n=4) than in those with the aa genotype (24.0+/-15.9 IU/l, n=27; P<0.02). The distribution of
ApaI, BsmI, TaqI RFLP VDR genotypes showed no significant relationship to the PASI score, serum
aspartate 2-oxoglutarate aminotransferase or
triglyceride levels, or age at onset. These results show that the VDR genotype contributes to the
liver dysfunction in patients with
psoriasis, although no correlation was found between VDR genotype and the skin eruptions of
psoriasis.