Genetic test Hairdx
It's an interesting time for us as we share a new and recent advance made at a genetic level, developed by an American company (www.hairdx.com) which may help in the fight against alopecia. In the words of Spencer Kobren, founder of the American Hair Loss Association:  “The genetic test by Hairdx for the early diagnosis of male baldness represents a great advance in the fight against hair loss. It is well known that the key to success in the treatment of androgenic alopecia (common hereditary baldness) is medical treatment in its early stages”. Introduction The genetic test for the detection of androgenic alopecia (AGA) is the first test which detects the risk of suffering from AGA before the symptoms actually appear. This means that we can diagnose the pathology in its initial stages and begin treatment at a time when the probabilities for success are greater The research has demonstrated a high risk of AGA with increasing phenotype expression (that the baldness develops) as we get older; approximately 65% in men and 50% of women suffer AGA at the age of 60 years. The actual diagnosis of AGA is carried out in a diagnostic clinic, based on the development of the alopecia when we already have bald or thinning areas. We know that a visible miniaturization isn´t detected until 50% of hair is lost from a certain area. Therefore, diagnosis depends on the development of a pattern of hair loss, implying that a significant amount of hair is lost before the patient can undergo a hair transplant procedure. This fact is important because the two medications which are currently FDA approved, (minoxidil and finasteride), are more efficient at stabilizing hair loss than in obtaining new growth in the follicles. In theory, until now, there is no therapy available which can recuperate lost hair follicles, only strengthen those units which have haven´t been miniaturized yet or are only partly miniaturized. So a test that could detect AGA could identify patients with high risk of alopecia and therefore offer them the opportunity of early treatment before the appearance of visible signs of thinning hair, when stabilization is our best and option for aesthetics. Our goal is to always stop the development of alopecia, not obtain a "hair growth" which returns that which has already been lost. The success against the pathology lies in its prevention. The Hairdx genetic test The advances made in human genetics have favored the discovery of the genetic bases of many illnesses. As the science progresses, new discoveries are more and more common. Even though the genes that cause AGA haven't been completely identified, current evidence shows that hereditary alopecia is based on the polygenic model (the confluence of various genes is what controls the pathology). The autosomal theories and the simple genomic transmission don´t correspond with the observed patterns. The efforts to identify the causal genes are centered on those that have known relations with mechanisms of hair growth. Not one single test has been able to reveal the association between the suspected genes and AGA, except in one case. 4 publications, containing a total of 2000 patients studied, have established the link between AGA and the androgen receptor gene (AR) of chromosome X. A particular polymorphism (or allele variation "G") of the androgen receptor gene (AR) is the one which was noted for having a high risk of developing AGA (approximately 70%). On the contrary, another protector allele (variant "A", less frequent) has been associated with a small possibility of developing AGA (70% probability of not developing AGA). If we also integrate the family history of AGA of the patient's parents, this will also help to validate the predictive power of the test. So, the patient with a positive test result for the variant AR G whose father has a history of AGA (NW 2A or more) has an 80% risk of suffering AGA. The patient who tests negative and whose father has no history of AGA has more than 90% probability of not suffering from AGA. The test offers a credible and reproducible method for determining the risk of suffering from AGA before actual symptoms appear. It also allows the identification of patients with AR variants of low risk in families with significant history of AGA, a relevant fact when it comes to planning medical and / or surgical strategy. Due to the current limitations on specificity (70, 80%), sometimes a second confirmation test is required before determining the need for medical therapy. The best trichological confirmation test is to determine the anagen/telogen quotient. A normal range for A/T is 12/1. As the AGA develops and progresses, this value may fall to 5/1. A documented drop in the A/T range implies the onset of alopecia. Although the genetic test is very sensitive, its poor specificity reduces its predictive value, so when then is the test better than clinical observation? Firstly, research has shown that men are reluctant to see a doctor unless they believe that there is something wrong (2007, interactive survey carried out by Harris for the AAFP) and, without visible signs of miniaturization, the majority won't go to the doctor for advice or treatment. What's more, many patients lose hair very gradually, and if they don't see lost hairs (in the sink, pillow or clothing for example) they don't realize that they are losing their hair until the pattern of alopecia is definitively developed. Therefore, given that the patients who have undergone the test are aware of the risk, they can keep a close eye and investigate the best options available and seek the best medical advice before deciding on the best treatment. On the contrary, there are patients who lose their hair rapidly, in the sense that the hair is not lost gradually, but due to a sudden change from anagen to telogen with the resulting hair loss occurring without the normal preliminary miniaturization. This group of patients would require a rapid intervention to disrupt the hair loss process. The absence of planning, the delay in diagnosing the problem and the use of alternative treatments give rise to unnecessary loss of hair. The continued use of treatments which are ineffective or unapproved for hair loss lead to many patients being misinformed as to which kind of therapy really works. A simple probe test, non-invasive and easy to carry out and repeat, can focus the attention of the patient to seek a better solution. Furthermore, other family members of the patient with AGA can become interested in researching his own genes. It may be that some patients who begin medical therapy never develop hair loss or require surgery. Types of Hairdx Test: 1. Genetic Test for the detection of Androgenic Alopecia (AGA) The objective of this test is to identify by genetic analysis certain genes in the chromosome X, the inheritance of the androgen receptor (AR) gene, which allows for the early detection of the risk of occurrence of alopecia. Until now the FDA approved remedies for androgenic alopecia (finasteride and minoxidl) are more effective at stabilizing hair loss then for the re-growth of hair, therefore the sooner the problem is identified then the better as this will improve results of the chosen treatment. Androgenic alopecia (AGA) in men (XY) and in women (XX) is a pathology which is inherited maternally, paternally or both via many genes present in the chromosome X. Until now, scientists have identified one gene, the receptor gene for the androgens, which is strongly associated with the early appearance of androgenic alopecia. In the case of men, a variant of this gene is studied in such a way that if the result gives positive for the high risk variant (variant G), there is a 70% possibility of developing alopecia if no preventative action is taken. In the case of women, the indications that prove the risk of alopecia are based on variations in the androgen receptor gene of the number of CAG repetitions (DNA nucleotide sequence for chromosome X). A short repetition of the CAG (cytosine-adenine-guanine) is associated with an increase in sensitivity to the androgens and consequently greater risk of developing alopecia Thanks to a scientifically backed result this information allows for the determination of the best treatment to adopt. It involves a quick and simple test which is carried out at the clinic. A sample of cheek cells is taken with a swab which is then sent to the laboratories in the USA. The result is received in about 3 weeks. 2. Genetic test for the response of men to Finasteride The androgen receptor gene has been identified as an important and determining factor in androgenic alopecia (AGA) or male pattern baldness. Some variants in the nucleotide sequence (DNA bases) in the androgen receptor gene, known as CAG repetitions, appear to determine the sensitivity of androgens in men. It has been demonstrated in independent studies by two research groups based in Japan that a lower number of CAG repetitions affect the patient's capacity to respond to the medication for AGA. Currently, one of the most prescribed medications, finasteride, acts by blocking the production of DHT (dihydrotestosterone), the hormone responsible for the miniaturization of hair in androgenic alopecia. For many years, finasteride therapy, which blocks the 5-alfa reductase responsible for the conversion of the testosterone in dyhydrotestosterone (DHT), has become one of the most important methods of treating AGA. This treatment is an effective means for stabilizing the loss of hair (85%) and in some cases to strengthen or promote normal growth of miniaturized hairs (66%). Other pharmaceutical therapies based on drugs from the same family, such as dutasteride, have been used but are not yet approved for use for treating AGA. However, these drugs have some side effects, (the most frequent being a 2% decrease in libido, as well as other rare effects such as gynecomastia and testicular pain). In spite of the small percentage of patients affected, the threat of suffering from side affects is enough to dissuade many patients into not taking the medication as they are unsure of the "risk-benefit" ratio of the treatment. An added value of this test is that many studies have demonstrated correlations between the lengths of the repetitions of CAG in the androgen receptor gene and a greater risk of developing benign prostatic hyperplasia (HPB). This means that these studies have shown "protector" benefit for the prostrate in those patients who take 1 mg finasteride for androgenic alopecia. This is a positive point when it comes to evaluating the risk-benefit ratio of the medication. By using this test it can be genetically determined if finasteride treatment would be beneficial by studying the number of repetitions in the CAG sequence of the androgenic receptor gene and its sensitivity. This implies not having to wait to see if the medication has any effect for each case and provides a more concrete and scientifically backed result and risk-benefit ratio. 3. Genetic Test of the Sensitivity of Women to Androgens Androgenic alopecia in women has the same hereditary pattern as in men. Women have 2 X chromosomes of which one is always active in a determined tissue while the second one remains inactive. The genetic design of the inactive X chromosome in terms of hair will decide whether said patient develops alopecia or not. The sensitivity to androgens is determined by the number of repetitions in the DNA sequence known as CAG in the inactive X chromosome. A small number of CAG repetitions imply a high sensitivity to androgens, which results in higher risk of developing alopecia. Scientific studies have demonstrated that those women with high sensitivity to androgens would benefit from anti- androgen treatment such as finasteride, espironolactona, etc. By means of these tests not only can it be determined if the origin of the alopecia is androgenetic, but also if there are high possibilities that the alopecia is advanced and if the current medical treatment would be beneficial.
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