Swyer Syndrome

Epidemiology and Etiology

Synonyms

• 46,XY complete gonadal dysgenesis Gonadal dysgenesis A number of syndromes with defective gonadal developments such as streak gonads and dysgenetic testes or ovaries. The spectrum of gonadal and sexual abnormalities is reflected in their varied sex chromosome (sex chromosomes) constitution as shown by the karyotypes of 45, X monosomy (Turner syndrome); 46, XX (gonadal dysgenesis, 46xx); 46, XY (gonadal dysgenesis, 46, xy); and sex chromosome mosaicism. Their phenotypes range from female, through ambiguous, to male. This concept includes gonadal agenesis. Wilms Tumor ( CGD CGD Chronic granulomatous disease (CGD), as the name implies, is a chronic disorder that is characterized by granuloma formation. This disorder is a consequence of defective phagocytic cells that are unable to produce bactericidal superoxide because of a defect in nicotinamide adenine dinucleotide phosphate (NADPH), the oxidase responsible for the respiratory burst in phagocytic leukocytes. Chronic Granulomatous Disease)
• Gonadal dysgenesis Gonadal dysgenesis A number of syndromes with defective gonadal developments such as streak gonads and dysgenetic testes or ovaries. The spectrum of gonadal and sexual abnormalities is reflected in their varied sex chromosome (sex chromosomes) constitution as shown by the karyotypes of 45, X monosomy (Turner syndrome); 46, XX (gonadal dysgenesis, 46xx); 46, XY (gonadal dysgenesis, 46, xy); and sex chromosome mosaicism. Their phenotypes range from female, through ambiguous, to male. This concept includes gonadal agenesis. Wilms Tumor, XY female type

Epidemiology

• 1 in 80,000–100,000 live births
• Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship have a higher risk of developing gonadoblastoma or dysgerminoma compared with the general population.

Etiology

The karyotype Karyotype The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere. Congenital Malformations of the Female Reproductive System of an individual with Swyer syndrome is 46 XY.

Swyer syndrome can be caused by various genetic abnormalities:

• Sex-determining region Y (SRY) gene mutation Gene Mutation Myotonic Dystrophies
  • Occurs in 20% of cases
  • SRY gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics plays a vital role in male sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria determination by triggering the transformation Transformation Change brought about to an organism’s genetic composition by unidirectional transfer (transfection; transduction, genetic; conjugation, genetic, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell’s genome. Bacteriology of gonadal tissue into testes Testes Gonadal Hormones.
  • The mutation Mutation Genetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations is most often a small deletion in the DNA-binding region of the SRY gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics on the Y chromosome Y chromosome The male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans and in some other male-heterogametic species in which the homologue of the X chromosome has been retained. Basic Terms of Genetics.
• Map3K1 gene mutation Gene Mutation Myotonic Dystrophies
  • Occurs in 18% of cases
  • Encodes a protein that aids in determining sexual characteristics during gestation
  • Mutations reduce the expression of SOX9 and SRY genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure and activate the expression of female-specific genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure (WNT, beta-catenin, and FOXL2).
• NR5A1 gene mutation Gene Mutation Myotonic Dystrophies
  • Occurs in 9% of cases
  • Encodes for the steroidogenic factor-1 nuclear receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors, a protein important for the production of sexual hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types/differentiation
• SOX9 gene mutation Gene Mutation Myotonic Dystrophies
  • Usually inhibits the creation of the female reproductive system, allowing for the development of male reproductive organs

Pathophysiology and Clinical Presentation

Pathophysiology

• Normal development until eighth week of gestation
• SRY gene mutation Gene Mutation Myotonic Dystrophies occurs → primordial gonads Gonads The gamete-producing glands, ovary or testis. Hormones: Overview and Types do not develop into testes Testes Gonadal Hormones → anti-Müllerian hormone ( AMH AMH A glycoprotein that causes regression of mullerian ducts. It is produced by sertoli cells of the testes. In the absence of this hormone, the mullerian ducts develop into structures of the female reproductive tract. In males, defects of this hormone result in persistent mullerian duct, a form of male pseudohermaphroditism. Primary Amenorrhea) and testosterone Testosterone A potent androgenic steroid and major product secreted by the leydig cells of the testis. Its production is stimulated by luteinizing hormone from the pituitary gland. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to dihydrotestosterone or estradiol. Androgens and Antiandrogens are not secreted → undeveloped male genitalia + development of uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy and vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor: Anatomy

Clinical presentation

• Phenotypically female
• Normal prepubertal development
• Tall stature (10–12 cm taller than those without Swyer syndrome [age and sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria matched])
• Cognition/intelligence: normal
• Behavioral phenotype Phenotype The complete genetic complement contained in the DNA of a set of chromosomes in a human. The length of the human genome is about 3 billion base pairs. Basic Terms of Genetics: normal
• Sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria development/ fertility: 
  • Primary amenorrhea Amenorrhea Absence of menstruation. Congenital Malformations of the Female Reproductive System
  • Infertility Infertility Infertility is the inability to conceive in the context of regular intercourse. The most common causes of infertility in women are related to ovulatory dysfunction or tubal obstruction, whereas, in men, abnormal sperm is a common cause. Infertility due to non-functioning ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries: Anatomy ( pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care is possible with ova donation)
  • ↓ Estrogen Estrogen Compounds that interact with estrogen receptors in target tissues to bring about the effects similar to those of estradiol. Estrogens stimulate the female reproductive organs, and the development of secondary female sex characteristics. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds. Ovaries: Anatomy due to non-functional ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries: Anatomy (streak gonads Gonads The gamete-producing glands, ovary or testis. Hormones: Overview and Types)
• Associations: ↑ risk of tumor Tumor Inflammation formation in the abnormal gonads Gonads The gamete-producing glands, ovary or testis. Hormones: Overview and Types (gonadoblastoma or dysgerminoma)

Diagnosis and Management

Diagnosis

• Mainly clinical, based on lack of puberty Puberty Puberty is a complex series of physical, psychosocial, and cognitive transitions usually experienced by adolescents (11-19 years of age). Puberty is marked by a growth in stature and the development of secondary sexual characteristics, achievement of fertility, and changes in most body systems. Puberty and secondary sexual characteristics Secondary Sexual Characteristics Precocious Puberty
  • Delayed or no breast development
  • Lack of pubic hair
  • Amenorrhea Amenorrhea Absence of menstruation. Congenital Malformations of the Female Reproductive System 
• Confirmed via karyotype Karyotype The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere. Congenital Malformations of the Female Reproductive System testing:
  • 46,XY: Swyer syndrome
  • 46,XX: primary ovarian failure
  • 45,XO: Turner syndrome Turner syndrome Turner syndrome is a genetic condition affecting women, in which 1 X chromosome is partly or completely missing. The classic result is the karyotype 45,XO with a female phenotype. Turner syndrome is associated with decreased sex hormone levels and is the most common cause of primary amenorrhea. Turner Syndrome
• Laboratory studies
  • Elevated follicle-stimulating ( FSH FSH A major gonadotropin secreted by the adenohypophysis. Follicle-stimulating hormone stimulates gametogenesis and the supporting cells such as the ovarian granulosa cells, the testicular sertoli cells, and leydig cells. Fsh consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity. Menstrual Cycle) and luteinizing ( LH LH A major gonadotropin secreted by the adenohypophysis. Luteinizing hormone regulates steroid production by the interstitial cells of the testis and the ovary. The preovulatory luteinizing hormone surge in females induces ovulation, and subsequent luteinization of the follicle. Luteinizing hormone consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity. Menstrual Cycle) hormone levels 
  • Tumor Tumor Inflammation markers should be tested to identify gonadoblastoma or dysgerminoma: alpha-fetoprotein Alpha-fetoprotein The first alpha-globulins to appear in mammalian sera during fetal development and the dominant serum proteins in early embryonic life. Hepatocellular Carcinoma (HCC) and Liver Metastases, beta-human chorionic gonadotropin, lactate dehydrogenase Lactate Dehydrogenase Osteosarcoma, and placental alkaline phosphatase Alkaline Phosphatase An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. Osteosarcoma.
• Adjunct studies
  • Genetic testing Genetic Testing Detection of a mutation; genotype; karyotype; or specific alleles associated with genetic traits, heritable diseases, or predisposition to a disease, or that may lead to the disease in descendants. It includes prenatal genetic testing. Myotonic Dystrophies and sequencing to determine defective gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics (does not affect treatment plan)
  • Transabdominal pelvic ultrasound
    • Evaluates status of Müllerian structures Müllerian structures Congenital Disorders of Sexual Development and ovaries Ovaries Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall and to the uterus by ligaments. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes). Ovaries: Anatomy
    • Shows streak gonads Gonads The gamete-producing glands, ovary or testis. Hormones: Overview and Types and normal Müllerian structures Müllerian structures Congenital Disorders of Sexual Development

Management

• Hormone replacement therapy Hormone Replacement Therapy Hormone replacement therapy (HRT) is used to treat symptoms associated with female menopause and in combination to suppress ovulation. Risks and side effects include uterine bleeding, predisposition to cancer, breast tenderness, hyperpigmentation, migraine headaches, hypertension, bloating, and mood changes. Noncontraceptive Estrogen and Progestins (to induce normal female puberty Puberty Puberty is a complex series of physical, psychosocial, and cognitive transitions usually experienced by adolescents (11-19 years of age). Puberty is marked by a growth in stature and the development of secondary sexual characteristics, achievement of fertility, and changes in most body systems. Puberty and the development of normal secondary sexual characteristics Secondary Sexual Characteristics Precocious Puberty):
  • Estrogen-based therapy
  • Cyclical estrogen Estrogen Compounds that interact with estrogen receptors in target tissues to bring about the effects similar to those of estradiol. Estrogens stimulate the female reproductive organs, and the development of secondary female sex characteristics. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds. Ovaries: Anatomy and progestin replacement therapy (for 50 years)
• Gonadectomy: indicated in all patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with Swyer syndrome due to risk of neoplasia in abnormal streak gonads Gonads The gamete-producing glands, ovary or testis. Hormones: Overview and Types
• Psychotherapy Psychotherapy Psychotherapy is interpersonal treatment based on the understanding of psychological principles and mechanisms of mental disease. The treatment approach is often individualized, depending on the psychiatric condition(s) or circumstance. Psychotherapy
• Fertility treatment
  • Only option for pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care is the use of donor ova
  • Since most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with Swyer syndrome have a hypotrophic uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy, they will require an elective cesarean section at 36 weeks to avoid uterine rupture Uterine Rupture A complete separation or tear in the wall of the uterus with or without expulsion of the fetus. It may be due to injuries, multiple pregnancies, large fetus, previous scarring, or obstruction. Antepartum Hemorrhage during labor.

Differential Diagnosis

The following conditions are differential diagnoses for Swyer syndrome:

• Congenital adrenal hyperplasia Hyperplasia An increase in the number of cells in a tissue or organ without tumor formation. It differs from hypertrophy, which is an increase in bulk without an increase in the number of cells. Cellular Adaptation: a group of rare autosomal recessive Autosomal recessive Autosomal inheritance, both dominant and recessive, refers to the transmission of genes from the 22 autosomal chromosomes. Autosomal recessive diseases are only expressed when 2 copies of the recessive allele are inherited. Autosomal Recessive and Autosomal Dominant Inheritance diseases characterized by defects in enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes of the adrenal glands Adrenal Glands The adrenal glands are a pair of retroperitoneal endocrine glands located above the kidneys. The outer parenchyma is called the adrenal cortex and has 3 distinct zones, each with its own secretory products. Beneath the cortex lies the adrenal medulla, which secretes catecholamines involved in the fight-or-flight response. Adrenal Glands: Anatomy involved in cortisol Cortisol Glucocorticoids, androgen, and aldosterone Aldosterone A hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium. Hyperkalemia synthesis Synthesis Polymerase Chain Reaction (PCR). Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may present with a wide range of symptoms, including virilization in females, salt-wasting leading to hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension and other electrolyte abnormalities, and premature Premature Childbirth before 37 weeks of pregnancy (259 days from the first day of the mother’s last menstrual period, or 245 days after fertilization). Necrotizing Enterocolitis completion of growth resulting in short stature.
• Complete androgen insensitivity syndrome Complete Androgen Insensitivity Syndrome Androgen Insensitivity Syndrome: an X-linked recessive X-Linked Recessive Duchenne Muscular Dystrophy condition in which a genetic mutation Mutation Genetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations causes a complete resistance Resistance Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow. Ventilation: Mechanics of Breathing to testosterone Testosterone A potent androgenic steroid and major product secreted by the leydig cells of the testis. Its production is stimulated by luteinizing hormone from the pituitary gland. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to dihydrotestosterone or estradiol. Androgens and Antiandrogens. As a result, individuals with this disorder are genotypically a male with 46,XY karyotype Karyotype The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere. Congenital Malformations of the Female Reproductive System, but without masculinization of external genitalia or virilization. It does not significantly impair female genital or sexual development.
• Hypergonadotropic ovarian dysgenesis Ovarian Dysgenesis Congenital Malformations of the Female Reproductive System: also known as 46,XX ovarian dysgenesis Ovarian Dysgenesis Congenital Malformations of the Female Reproductive System, a primary defect of the development of the ovary that leads to premature ovarian failure Premature ovarian failure Primary ovarian insufficiency (POI) is a condition resulting from the depletion or dysfunction of the ovarian follicles, leading to cessation of ovulation and menses before age 40. Primary ovarian insufficiency is primarily idiopathic. Patients present with signs and symptoms of menopause prior to age 40, including oligo- or amenorrhea, vaginal dryness (often leading to dyspareunia), and infertility. Primary Ovarian Insufficiency in a woman with a normal karyotype Karyotype The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere. Congenital Malformations of the Female Reproductive System (46,XX). The failure of gonadal development is caused by resistance Resistance Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow. Ventilation: Mechanics of Breathing to gonadotrophin stimulation.