Benign Prostatic Hyperplasia (BPH) is the age-related overgrowth of specific prostate tissues, which often progresses to enlargement of the prostate. The enlarged prostate can constrict the urethra, causing various lower urinary tract symptoms. Androgen Receptor gene variations have been associated with the risk for developing Benign Prostatic Hyperplasia (BPH).

Certain variants of the nucleotide sequence on the Androgen Receptor gene, known as CAG repeats, appear to determine androgen sensitivity in men. Lower numbers of CAG repeats have been associated with increased androgen sensitivity. This sensitivity and associated genotype have been associated with a myriad of physiologic effects. Three independent studies from two research groups in the U.S. and Japan, demonstrated that a lower number of CAG repeats is associated with a higher risk of developing BPH.

Currently there are two categories of medical drug therapies for the treatment of BPH, 5-alpha reductase inhibitors and alpha-andrenergic blockers. Of these, only the 5-alpha reductase inhibitors (i.e. finasteride) can shrink the prostate. Finasteride works by blocking the production of the androgen called DHT (dihydrotestosterone), a hormone that plays a pivotal role in BPH. For many years finasteride therapy, which blocks the enzyme 5-alpha reductase from converting testosterone into dihydrotestosterone (DHT), has become a mainstay to treat BPH. This treatment is an effective means to reduce prostate size and lower urinal tract symptoms (LUTS). Other medication therapies in the same drug family, such as dutasteride, have also been used for this purpose.

Studies have shown the long term efficacy of 5-alpha reductase inhibitors in reducing prostate size and relieving LUTS. Furthermore, there is evidence that lower finasteride doses (1mg to 2.5mg per day) can effectively control prostate enlargement and LUTS versus the standard 5mg/day dose. The 1mg/day dose of finasteride is prescribed for androgenetic alopecia (AGA). Therefore, patients with AGA may find the additional benefit of reduced BPH risk while taking finasteride.

Genetic sequencing of the androgen receptor gene offers a novel approach to assist doctors and patients in determining a patient's androgen sensitivity. The new HairDX (RxR) Genetic Test has been designed to determine the number of CAG repeats of a patient’s androgen receptor gene, and thereby assess if the patient carries the androgen receptor gene variant associated with an increased risk for developing BPH.

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