RESUMO
Cytochromes P-450 are a supergene family of enzymes involved in the metabolism of a wide range of endogenous and foreign compounds. The existing genetic variations of the distinct isozymes lead to interindividually different metabolic capacity. Since vitamin A, endogenous retinoids and their natural metabolites are morphogenic for the sebaceous gland, we investigated the polymorphisms of cytochrome P-450 1A1, as being one of the most active isozymes involved in their interconversion. From the known mutations, two were investigated; an additional cleavage site for MspI in the 3'-flanking region identified as a thymine-to-cytosine transition 1,194 bp downstream of exon 7 (m1) and an adenine-to-guanine transition at position 4889 in exon 7 (m2). We studied 96 acne patients for m1 and m2 mutations by restriction fragment length polymorphism and allele-specific polymerase chain reaction, respectively, and compared the results with 408 reference individuals. No statistically significant difference was found in the distribution of m2 alleles; the frequency was 3.13 and 3.06% of the alleles, respectively (odds ratio = 1.02, confidence limits 0.41-2.52, p = 0.96). In contrast, a trend to an overrepresentation of m1 alleles in acne patients was observed; allele frequency was 8.33 in the patients and 6.99% in the control subjects, respectively (odds ratio 1.21, 95% confidence limits 0.68-2.16, p = 0.52). As the m1 mutation might define a marker for alterations on regulatory sites, the biological efficacy of natural retinoids could be greatly impaired by their rapid metabolism to inactive compounds. The resulting deficit of active natural retinoids may lead to abnormal sebocyte differentiation and hyperkeratinization of the follicular canal implicating the development of acne in some patients.
