Androgenetic alopecia (androgenetic alopecia) - Gen AR.

Androgenic alopecia is a common form of hair loss in men and women. In males, also it is known as male pattern baldness. The hair is lost in a well - defined pattern beginning above both temples. Over time, the hairline recedes to make a characteristic "M". Hair also decreases at the crown and often progresses to complete baldness or partial. For its part, the pattern of hair loss in women differs from male pattern baldness. In these cases, the hair becomes thinner all over the head, and the hairline does not recede. Androgenic alopecia in women rarely leads to total baldness.

Androgenic alopecia in men has been associated with other disorders, including coronary heart disease and prostate hyperplasia. In addition, prostate cancer, disorders of insulin resistance, such as diabetes and obesity, and hypertension. In women, it is associated with an increased risk of polycystic ovary syndrome (PCOS), characterized by a hormonal imbalance that can cause irregular menstruation, acne, hirsutism and weight gain.

This process is due to mutations in the AR gene, located on the long arm of chromosome X (Xq12). This gene encodes a protein called androgen receptor. Androgens are important for male sexual normal development before birth and during puberty. Androgen receptors allow the body to respond appropriately to these hormones. Receptors are present in many body tissues, where androgens bind. The resulting androgen-receptor complex binds to DNA and regulates the activity of genes responsive to androgens. The androgen receptor helps guide the development of male sexual characteristics. Androgens and androgen receptors also have other important functions in both males and females, such as regulating hair growth and sex drive. In a region of the AR gene, a DNA segment known as CAG repeats several times. This segment is called CAG triplet or trinucleotide repeat. In most people, the number of CAG repeats in the AR gene ranges from less than 10 to about 36 times.

Alterations in the AR gene are associated with increased risk of androgenic alopecia. These variations result from small changes in the number or base pairs that comprise the AR gene. These genetic changes appear to be more common in men with hair loss that starts at an early age. It is likely that variations of the AR gene may increase the activity of androgen receptors in the scalp. Although androgenetic alopecia is related to the effects of androgens on hair growth, it is unclear how changes in the AR gene increase the risk of hair loss in men and women with this condition.

The inheritance pattern of androgenic alopecia is uncertain because many genetic and environmental factors may be involved. However, this condition tends to cluster in families, and have a close relative with a pattern of hair loss appears to be a risk factor for the development of androgenic alopecia.

Tests in IVAMI: in IVAMI perform detection of mutations associated with androgenic alopecia, by complete PCR amplification of the exons of the AR gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).