What is Intersex and/ or DSD?
DSD is a medical term for differences of sex development, or intersex. Intersex is also a term for biologically not having strictly male or female sex characteristics. Having one of many differences of sex development is the reason this can occur. To clarify, intersex or differences of sex development refer to the biology and/ or appearance (phenotype) of an individual, where as gender (how a person identifies) and sexual orientation (who a person is attracted to) are different things. Click here for an interactive visual that can help explain, entitled the Genderbread person.
With these differences, variations in the usual path of prenatal development of parts of the reproductive system cause traits that we don’t usually expect in typical boys and girls. There may be unexpected patterns of the X and Y chromosomes (karyotype), gonads (the term for either testes, ovaries, or ovotestes), internal reproductive and urinary organs (uterus, fallopian tubes, bladder and urethra), or different looking genitalia. Potential causes include genetic differences, changes in number of sex chromosomes, variations in gonads, exposure to unusual levels of sex hormones, or levels of response to hormones. DSD are not life-threatening, although they may be associated with a serious medical condition such as salt-wasting congenital adrenal hyperplasia (SW CAH). Each case can be unique, and anyone with DSD has the same chances to be healthy and live happy and productive lives as anyone else.
Understanding sex development is key to understanding how intersex traits happen. Sex development is a process that takes place in multiple steps. There are key “branch points” during embryonic and fetal life that shape a baby’s chemistry and anatomy. This link on the website of Hospital for Sick Children in Toronto, Canada directs you to an animated explanation of the developmental pathways of many DSD.
Definitions
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Karyotype is a test that gives a picture of all of the chromosomes present in a single one of your cells. When looking for intersex traits, your doctor may look specifically at the sex chromosomes of a karyotype which are typically XX or XY, but can have many variations, such as XXY, XXXY or others. This test doesn’t provide an exact diagnosis, but it can provide clues to where to look for more information. -
Gonad is generic term used to describe both testes, ovaries, or an ovotestes. It is especially useful when a structure might not appear typical.
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Sex is the physical characteristics of “male” or “female”. A baby develops internal structures that usually can become testes or ovaries at about 7 weeks of gestation.
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Two parts make up sex development. Sex determination is the process of development in gonads. Sex differentiation is the process of development of the internal and external genitalia, under the influence of what is secreted by the gonads. Both of these together equal sex development.
All fetuses begin life in a sexually “neutral” or “bipotential” state, with same internal and external structures. Internal structures, or “gonads” are at first neither testes nor ovaries, and genitalia are undeveloped, neither male nor female. Whether a child develops as a boy or a girl depends on the effects of a whole lot of genes, not just having an X or Y chromosome.
What we think of as the typical route of development is first the chromosomal sex, then genetic sex, followed by gonadal sex, then hormonal, followed by phenotypic sex (genitalia), and finally gender. That is a complicated process!
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Phenotype is the physical appearance, or how you look on the outside.
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Gender is how one feels on the inside, typically male or female. This may or may not match their phenotype, or how they appear on the outside. This is a social and cultural role as well as an identity and there is a wide spectrum of how one can feel.
Things that can sometimes, but not always, contribute to gender are genetics, prenatal or possibly postnatal hormones, social, cultural, and environmental influences.
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Sexual orientation is who a person is attracted to, such as males, females, or diverse individuals. This is separate from gender and sex or sex development. Sexual orientation is the same statistically for those who are intersex as it is for those in the general population.
Examples of Development
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Were you taught that XX = female and XY = male? While that may be the typical expectation, it’s not always true. Just like there is a spectrum of height and eye color, there is a spectrum in reproductive development as well. Sex development is complex and can follow many different patterns, but here is what usually happens in an abbreviated form for most males and females.
The pattern for most boys: 46 XY chromosomes are present with testes genes that cause the testes to develop and secrete androgens (male hormones like testosterone). The receptors function to allow for development, finally ending with the epididymis, vas deferens, penis, and scrotum.
The pattern for most girls: 46 XX chromosomes are present with ovary genes that cause the ovaries to develop with no hormones during fetal development, ending with fallopian tubes, uterus, clitoris, vagina and labia.
Just like there are many ways to get to the same destination, there are many ways to end up male or female that are not along these typical pathways.
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Congenital Adrenal Hyperplasia (CAH) is a group of differences caused by a genetic mutation affecting the adrenal glands, and can occur in both 46 XX and 46 XY individuals. The most common is 21-hydroxylase deficiency (21-OHD), which is inherited along a spectrum of mild to more diverse symptoms. Classical CAH, is usually detected in infancy through early childhood. The milder form, called Non-classical CAH (NCAH), may cause symptoms at anytime from infancy through adulthood. Non-classical CAH is a much more common than Classical CAH, but medication and quality care can help make it possible to have healthy, typical lives.
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46, XX salt-wasting CAH (SWCAH) is due to genetic mutations in enzymes of the adrenal gland, which sit on top of the kidneys. These enzymes are chemicals needed by the adrenal gland to make cholesterol into three important hormones that help to regulate the body’s functions: cortisol, aldosterone and androgen. If one of the enzymes needed to make cortisol and/or aldosterone is not working properly, the adrenal glands fail to work in a balanced way. They make too little cortisol and/or aldosterone, and more androgen than usual. When there is not enough cortisol or aldosterone, babies with SW CAH may become very sick. They can become dehydrated and lose blood pressure if not treated urgently. A baby with XX SW CAH has a uterus and ovaries, but the genital appearance may be female-typical, male-typical or in between. Babies with other types of CAH may not have genital difference.
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Androgen Insensitivity Syndrome (AIS) occurs when an individual has one X and one Y chromosome (what is thought to be the typical male presentation), but the body is unable to respond to androgens (male sex hormones like testosterone). During prenatal development, an individual with complete AIS (CAIS) will develop female external genitalia, while a person with partial AIS (PAIS) may have external genitalia that appear mainly female, or mainly male, or anything on the spectrum between. Because the testes function, a hormone is secreted that causes the uterus and fallopian tubes to not develop. The vagina may be of any length, from short to typical. During puberty, development includes feminine appearance of breasts and hip shape. The testes are immature, and do not have viable sperm. Stature resembles those genetically related with Y chromosomes, so the individual is likely to have a similar height to the biological males in the family. In PAIS, there is an increased risk of cancer developing in the testes, so surgical removal is commonly recommended. The risk of cancer development in CAIS is much lower (studies show lower than breast cancer), and many are choosing to keep their gonads for a more natural puberty where they benefit from their own hormone production and a process called aromatization. Aromatization is where excess testosterone is converted in to estrogen.
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46, XY complete gonadal dysgenesis (Swyer syndrome) occurs when a baby is born with one X and one Y chromosome, but the testes do not develop. During prenatal development, these babies develop typical female external genitalia and a small uterus. The underdeveloped gonads become fibrous tissue called “streaks”, neither testis nor ovary. These children need to take hormones for puberty. Because there is an increased risk of cancer developing in streak gonads, removal is commonly recommended.
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46, XY partial gonadal dysgenesis in a baby with XY chromosomes causes development of testes that do not function at the same level as typical testes. Sometimes the testes disappear or regress. Babies’ genitals can vary in appearance depending on how much the testes function. Tumors occur about 20-30 % of the time. (reference).
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Gonadal dysgenesis/ Mixed gonadal dysgenesis: In partial gonadal dysgenesis, the testes function, but not at the same level as typical testes, resulting in ambiguous genitalia at birth. In mixed gonadal dysgenesis, a streak gonad develops on one side, and a partially developed testis on the other side. As the internal gonads in both of these conditions are more prone to develop cancer, surgical removal is usually recommended. Hormone supplementation is then required to promote development at puberty. Chromosomal pattern is often mixed, with any combination of 46, XX, 46, XY, and 45, X patterns.
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In 5 alpha reductase-3 deficiency (5 ARD deficiency ) and 17beta-hydroxysteroid dehydrogenase-3 deficiency (17 BHSD deficiency), genetic mutations in XY babies with testes result in unusual levels of sex hormones. All hormones are made from cholesterol by enzymes, and these mutations change the function of enzymes needed to make androgens. Children with 5 ARD deficiency and 17 BHSD deficiency have XY chromosomes and testes, but their testes make a version of androgen that is weaker than usual. The appearance of babies’ genitalia may range from female-typical or vary along the spectrum of genital difference.At puberty, when levels of androgen increase dramatically, the large amount of weaker androgens can cause male-typical changes, like deepening of the voice, growth of facial hair, and muscle development. If a child does not want these changes, puberty can be blocked by medication. There are reports of fertility in adults with 5 ARD, but not 17 BHSD deficiency.
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Ovotesticular DSD: In typical sex development, the fetus develops two tiny organs called “proto-gonads”. In typical males, those proto-gonads become testes, whereas in females, those proto-gonads become ovaries. In some circumstances the proto-gonad may become an ovotestis, which means it contains some cellular elements of ovaries as well as some cellular elements of testes. Although a person may be born with two ovotestes, it is much more common for a person to be born with a typical ovary on one side but an ovotestis on the other, or one testis with an ovotestis on the other side. Some people with ovotestes look fairly female-typical at birth, some look fairly male-typical, and some look more in-between. Many different chromosomal and anatomical combinations have been observed in people with ovotestes. Diagnosis of ovotestes will not reveal the sex chromosomes, genetic composition, or internal anatomy of a patient. Other tests are required to determine those elements. The testicular portion of ovotestes increases the risk of cancer development. For this reason, when ovotestes are diagnosed, usually the testicular portion is surgically removed. In a patient who identifies as male, the ovarian tissue may also be removed.
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Girls with typical 46, XX chromosomes and ovaries may have atypical development of internal structures such as the vagina, the uterus, and the Fallopian tubes. MRKH Syndrome sometimes also involves differences in development of the skeleton, internal ears, and in rarer cases, the heart, fingers and toes.
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Steroidogenic factor 1 (SF1, NR5A1) is a type of receptor that regulates several genes involved in adrenal and gonadal development, steroidogenesis, and reproductive development. Gonadal dysgenesis and primary adrenal failure can be caused by a mutation in SF1, as well as 46,XY partial gonadal dysgenesis and typical adrenal function. The phenotype can appear anywhere on the spectrum from typical “male” to typical “female”.
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Leydig cell hypoplasia is an autosomal recessive condition in which the LHCGR gene does not function typically which leads to a difference in sex development. Two types of LCH have been defined (Toledo, 1992). Those with type I, have complete inactivation of LHCGR, and may have a typical female phenotype with 46,XY chromosomes, low testosterone and high LH levels. They can achieve secondary sex characteristics with hormone replacement. Those with type II, caused by partial inactivation of the gene, can have a phenotype (appearance) anywhere along the spectrum of development. 46, XX Females with inactivating mutations in the LHCGR gene may have difficulty with follicular development and ovulation.
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Hypospadias is when the urethral meatus, or the urethral opening, is located along the underside, rather than at the tip of the penis. In some hypospadias, the meatus may be located on the underside of the penis, in the glans. For some with hypospadias, the urethra may be open from mid-shaft out to the glans, or sometimes the urine exits the bladder behind the penis. Hypospadias is common. There are groups where men and boys with hypospadias, their families, and parents of boys with hypospadias can receive further support, such as the Hypospadias and Epispadias Association (HEA). Many are members in both HEA and AIS-DSD Support Group.
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Klinefelter Syndrome is a spontaneous genetic difference in males caused by an extra X chromosome at conception. It occurs in one in every 500-1000 male births but can increase in children born with different neurologically diverse. Having another X chromosome can result in a broad spectrum of differences. These include behavioral struggles, dyspraxia (balance and coordination issues), learning difficulties and speech differences. As they reach puberty, testes may not grow to typical size and breast tissue may devleop, a condition known as gynecomastia. Those with kleinfelters syndrome might also have psychological challenges or become more susceptible to illness than developmentally typical boys. Affected men may sometimes have a low libido, and need extra care to prevent osteoporosis at an earlier age than the general population. At other times, there are no outward physical or psychological symptoms, and it is only discovered by chance when the person is being investigated for infertility. Advances in fertility have made it possible to extract viable sperm for some affected men, and a correlation between viable sperm and early treatment has been made.
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There are many more diagnoses not in our list. Even after rigorous genetic testing, sometimes intersex traits and differences of sex development can occur with no clear diagnosis available. In other cases, genetic testing wasn’t accessible when individuals were discovering they were intersex. Advances in genetics and the understanding human development is still occurring at a rapid pace, yet, it may be a long time before we have all the answers. Whether or not you have a clear diagnosis, or if you have one of the many of the diagnoses that are not listed here, you will still be welcomed and highly valued in our community.
