Virilization
Encyclopedia
In biology and medicine, virilization refers to the biological development of sex differences, changes that make a male
body different from a female
body. Most of the changes of virilization are produced by androgen
s. Virilization is most commonly used in three medical and biology of gender
contexts: prenatal sexual differentiation
, the postnatal changes of normal male puberty
, and excessive androgen effects in girls or women.
, thinning and rugation of the scrotum
, growth of the phallus
, and closure of the urethral groove
to the tip of the penis
. In this context masculinization is synonymous with virilization.
conditions.
Prenatal virilization (or masculinization) of a genetically female fetus can occur when an excessive amount of androgen is produced by the fetal adrenal gland
s or is present in maternal blood. In the severest form of congenital adrenal hyperplasia
, complete masculinization of a genetically female fetus results in an apparently normal baby boy with no palpable testes. More often, the virilization is partial and the genitalia are ambiguous.
It can also be associated with progestin-induced virilisation
.
. Examples of undervirilization are androgen insensitivity syndrome
, 5 alpha reductase deficiency, and some forms of congenital adrenal hyperplasia
.
, in which testosterone
changes a boy's body into a man's. These effects include growth of the penis and testes, accelerated growth, development of pubic hair
, and other androgenic hair of face, torso, and limbs, deepening of the voice, increased musculature, thickening of the jaw, prominence of the neck cartilage, and broadening of the shoulders.
, accelerated growth and bone maturation, increased muscle strength, acne
, and adult body odor. In a boy, virilization may signal precocious puberty
, while congenital adrenal hyperplasia
and androgen producing tumors (usually) of the gonad
s or adrenals are occasional causes in both sexes.
enlargement, increased muscle strength, acne, hirsutism
, frontal hair thinning, deepening of the voice, and menstrual disruption due to anovulation
.
Some of the possible causes of virilization in women are:
Male
Male refers to the biological sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization...
body different from a female
Female
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...
body. Most of the changes of virilization are produced by androgen
Androgen
Androgen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...
s. Virilization is most commonly used in three medical and biology of gender
Biology of gender
Biology of gender can have different meanings, depending on the meaning of gender.* In medicine and biology it usually refers to the biology of sexual dimorphism, e.g...
contexts: prenatal sexual differentiation
Sexual differentiation
Sexual differentiation is the process of development of the differences between males and females from an undifferentiated zygote...
, the postnatal changes of normal male puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
, and excessive androgen effects in girls or women.
Prenatal virilization
In the prenatal period, virilization refers to closure of the perineumPerineum
In human anatomy, the perineum is a region of the body including the perineal body and surrounding structures...
, thinning and rugation of the scrotum
Scrotum
In some male mammals the scrotum is a dual-chambered protuberance of skin and muscle containing the testicles and divided by a septum. It is an extension of the perineum, and is located between the penis and anus. In humans and some other mammals, the base of the scrotum becomes covered with curly...
, growth of the phallus
Phallus
A phallus is an erect penis, a penis-shaped object such as a dildo, or a mimetic image of an erect penis. Any object that symbolically resembles a penis may also be referred to as a phallus; however, such objects are more often referred to as being phallic...
, and closure of the urethral groove
Urethral groove
The primary urethral groove or urethral groove is a temporary linear indentation on the underside of the male penis during embryonic development....
to the tip of the penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...
. In this context masculinization is synonymous with virilization.
High
Prenatal virilization of genetic females and undervirilization of genetic males are common causes of ambiguous genitalia and intersexIntersex
Intersex, in humans and other animals, is the presence of intermediate or atypical combinations of physical features that usually distinguish female from male...
conditions.
Prenatal virilization (or masculinization) of a genetically female fetus can occur when an excessive amount of androgen is produced by the fetal adrenal gland
Adrenal gland
In mammals, the adrenal glands are endocrine glands that sit atop the kidneys; in humans, the right suprarenal gland is triangular shaped, while the left suprarenal gland is semilunar shaped...
s or is present in maternal blood. In the severest form of congenital adrenal hyperplasia
Congenital adrenal hyperplasia
Congenital adrenal hyperplasia refers to any of several autosomal recessive diseases resulting from mutations of genes for enzymes mediating the biochemical steps of production of cortisol from cholesterol by the adrenal glands ....
, complete masculinization of a genetically female fetus results in an apparently normal baby boy with no palpable testes. More often, the virilization is partial and the genitalia are ambiguous.
It can also be associated with progestin-induced virilisation
Progestin-induced virilisation
Maternal use of androgens or high doses of certain weakly androgenic synthetic progestogens structurally related to testosterone can masculinize the external genitalia of a female fetus during susceptible times in pregnancy....
.
Low
Undervirilization can occur if a genetic male cannot produce enough androgen or the body tissues cannot respond to it. Extreme undervirilization occurs when no significant androgen can be produced or the body is completely insensitive to it, and results in a female body. Partial undervirilization produces ambiguous genitalia part-way between male and female. The mildest degree of undervirilization may be a slightly small penis with hypospadiasHypospadias
Hypospadias is a birth defect of the urethra in the male that involves an abnormally placed urinary meatus...
. Examples of undervirilization are androgen insensitivity syndrome
Androgen insensitivity syndrome
Androgen insensitivity syndrome is a condition that results in the partial or complete inability of the cell to respond to androgens. The unresponsiveness of the cell to the presence of androgenic hormones can impair or prevent the masculinization of male genitalia in the developing fetus, as...
, 5 alpha reductase deficiency, and some forms of congenital adrenal hyperplasia
Congenital adrenal hyperplasia
Congenital adrenal hyperplasia refers to any of several autosomal recessive diseases resulting from mutations of genes for enzymes mediating the biochemical steps of production of cortisol from cholesterol by the adrenal glands ....
.
Normal virilization
In common as well as medical usage, virilization often refers to the process of normal male pubertyPuberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
, in which testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
changes a boy's body into a man's. These effects include growth of the penis and testes, accelerated growth, development of pubic hair
Pubic hair
Pubic hair is hair in the frontal genital area, the crotch, and sometimes at the top of the inside of the legs; these areas form the pubic region....
, and other androgenic hair of face, torso, and limbs, deepening of the voice, increased musculature, thickening of the jaw, prominence of the neck cartilage, and broadening of the shoulders.
Abnormal childhood virilization
Virilization can occur in childhood in either boys or girls due to excessive amounts of androgens. Typical effects of virilization in children are pubic hairPubic hair
Pubic hair is hair in the frontal genital area, the crotch, and sometimes at the top of the inside of the legs; these areas form the pubic region....
, accelerated growth and bone maturation, increased muscle strength, acne
Acne vulgaris
Acne vulgaris is a common human skin disease, characterized by areas of skin with seborrhea , comedones , papules , pustules , Nodules and possibly scarring...
, and adult body odor. In a boy, virilization may signal precocious puberty
Precocious puberty
As a medical term, precocious puberty describes puberty occurring at an unusually early age. In most of these children, the process is normal in every respect except the unusually early age, and simply represents a variation of normal development. In a minority of children, the early development is...
, while congenital adrenal hyperplasia
Congenital adrenal hyperplasia
Congenital adrenal hyperplasia refers to any of several autosomal recessive diseases resulting from mutations of genes for enzymes mediating the biochemical steps of production of cortisol from cholesterol by the adrenal glands ....
and androgen producing tumors (usually) of the gonad
Gonad
The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, spermatozoon and egg cells are gametes...
s or adrenals are occasional causes in both sexes.
Virilization in adolescent or adult women
Virilization in a woman can manifest as clitoralClitoris
The clitoris is a sexual organ that is present only in female mammals. In humans, the visible button-like portion is located near the anterior junction of the labia minora, above the opening of the urethra and vagina. Unlike the penis, which is homologous to the clitoris, the clitoris does not...
enlargement, increased muscle strength, acne, hirsutism
Hirsutism
Hirsutism or frazonism is the excessive hairiness on women in those parts of the body where terminal hair does not normally occur or is minimal - for example, a beard or chest hair. It refers to a male pattern of body hair and it is therefore primarily of cosmetic and psychological concern...
, frontal hair thinning, deepening of the voice, and menstrual disruption due to anovulation
Anovulation
An anovulatory cycle is a menstrual cycle during which the ovaries do not release an oocyte. Therefore, ovulation does not take place. However, a woman who does not ovulate at each menstrual cycle is not necessarily going through menopause...
.
Some of the possible causes of virilization in women are:
- Polycystic ovary syndromePolycystic ovary syndromePolycystic ovary syndrome is one of the most common female endocrine disorders. PCOS is a complex, heterogeneous disorder of uncertain aetiology, but there is strong evidence that it can to a large degree be classified as a genetic disease....
- AndrogenAndrogenAndrogen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...
-producing tumors of the- ovaries
- adrenal glands
- pituitary gland
- HypothyroidismHypothyroidismHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
- Anabolic steroidAnabolic steroidAnabolic steroids, technically known as anabolic-androgen steroids or colloquially simply as "steroids", are drugs that mimic the effects of testosterone and dihydrotestosterone in the body. They increase protein synthesis within cells, which results in the buildup of cellular tissue ,...
exposure - Congenital adrenal hyperplasia due to 21-hydroxylase deficiencyCongenital adrenal hyperplasia due to 21-hydroxylase deficiencyCongenital adrenal hyperplasia due to 21-hydroxylase deficiency , in all its forms, accounts for over 95% of diagnosed cases of congenital adrenal hyperplasia, and "CAH" in most contexts refers to 21-hydroxylase deficiency...
(late-onset) - Hormone replacement therapy (female-to-male)Hormone replacement therapy (female-to-male)Hormone replacement therapy for transgender gender variant and transsexual introduces hormones associate with the gender that the patient identifies with...
- Conn's Syndrome
See also
- Sexual differentiationSexual differentiationSexual differentiation is the process of development of the differences between males and females from an undifferentiated zygote...
- Secondary sex characteristicSecondary sex characteristicSecondary sex characteristics are features that distinguish the two sexes of a species, but that are not directly part of the reproductive system. They are believed to be the product of sexual selection for traits which give an individual an advantage over its rivals in courtship and aggressive...
s - Ambiguous genitalia
- AndrogenAndrogenAndrogen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...
- ClitoromegalyClitoromegalyClitoromegaly is an abnormal enlargement of the clitoris ....
- HirsutismHirsutismHirsutism or frazonism is the excessive hairiness on women in those parts of the body where terminal hair does not normally occur or is minimal - for example, a beard or chest hair. It refers to a male pattern of body hair and it is therefore primarily of cosmetic and psychological concern...