Androgen action disorders

DISORDERS OF ANDROGEN ACTION PRODUCE FEMINIZATION IN MALES... 

Steroid Sa-reductase deficiency is an autosomal recessive disorder that causes decreased conversion of testosterone to dihydrotestosterone and decreased androgen action that is particularly critical during sexual development. 

Definitive evidence that dihydrotestosterone (DHT) is a potent androgen with its own important physiological and pathophysiological actions, separate from those of testosterone, was provided by two reports in 1974 of a rare inborn disorder of male phenotypic sexual differentiation caused by a deficiency in 5a-reductase, the enzyme that converts testosterone to DHT. The reduction in the conversion of testosterone to DHT by 5a-reductase, which underlies this syndrome, leads to a specific developmental defect in the formation of the male external genitalia and the prostate. Males with this genetic disorder exhibit a striking phenotype, in which the internal genitalia are normal... 

Acne results from disordered function of the pilosebaceous follicle whereby abnormal keratin and sebum (the production of which is androgen driven), form debris which plugs the mouth of the follicle. Propionibacterium acnes colonises the debris. Bacterial action releases inflammatory fatty acids from the sebum. 

XY disorder of sex development with ambiguous genitalia (former male pseudohermaphroditism) is most frequently caused by an abnormal plasma testosterone level or an abnormal testosterone response. The most common causes are disorders in androgen synthesis or action. 

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