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Swyer syndrome

Swyer syndrome is very specific rare health condition which was first described by Dr. Swyer G.I. in 1955 – it is actually gonadal disgenesis (inherited disorder) which appeared only during puberty. It is typical Disorder of Sex Development (DSD) with population incidence 1: 100 000. Syndrome is characterized by a 46 XY karyotype (male karyotype, male sex chromosomes) with normal female appearance (female phenotype) which includes normal female external genitalia, hypoplastic (small) uterus and streak ovaries. Sometimes patients could have normal uterus and Fallopian tubes but always not developed ovaries. Girls with this syndrome usually have amenorrhea (never have menstrual periods) and not developed breasts. Ovaries contain fibrous tissue but no follicles can be found – these ovaries don’t have any hormonal or reproductive potential.

Before puberty syndrome of Swyer is not visible and it is very difficult to identify. Starting from puberty, usually healthy ovaries increase production of female hormones (estrogen and progesterone) which triggers menstrual cycles, breast development and female body changes. Unfortunately during Swyer syndrome streak ovaries are not able to produce needed female hormones.

Swyer syndrome affects embryo early development through mutated SRY gene. According to chromosomal analysis, this genetic disorder develops because of deletion (missing part of genetic information) of short arm of Y chromosome – defect is found in parts responsible for gonadal (ovarian) development. Actually absence of development in puberty is correlated with absence of development of internal sex organs (uterus, Fallopian tubes, and ovaries) and correlated also with the Y chromosome defect.

Sometimes Swyer syndrome called “46,XY complete gonadal dysgenesis” which fully explains deficit of ganadal (ovarian) development. This syndrome can occur as the result of new gene mutation or can be inherited in an autosomal dominant, autosomal recessive, X-linked or Y-linked manner.

Health experts noted easy and fast transformation of not developed ovarian tissue into cancerous cells. This is why most experts recommend surgical removal of streak (not developed) ovaries in puberty (as soon as possible). About 30% of females with Swyer syndrome develop ovarian cancer or benign tumors formed from ovarian fibrous tissue.

Swyer syndrome

Swyer syndrome

Most patients with syndrome of Swyer are usually raised as girls and have full female gender identity (female appearance, female character and female behavior) but they never produce eggs, never have menstrual periods and are not able to become pregnant. Lack of development in puberty can be compensated by hormones. Thanks to modern Assisted Reproductive Technologies (ART) women can become mothers with donated eggs or donated embryo.

It was already mentioned that Swyer syndrome usually affects reproductive system but sometimes it can affect also nerve system (neuropathy) and skeletal system (campomelic dysplasia, severe skeletal abnormalities).

Swyer syndrome – symptoms

Usually all symptoms appear during early puberty:

  • Delayed puberty;
  • Absence of menstrual periods (primary amenorrhea);
  • Absence of breast development (flat or very small breasts);
  • Increased size of clitoris;
  • High growth;
  • Pubic hair deficit (minimal development of pubic hair);
  • Primary infertility;
  • Increased level of some pituitary hormones – FSH (follicle-stimulating hormone) and LH (luteinising hormone);
  • Decreased levels of female hormones (mainly estrogens).

Swyer syndrome – diagnosis

Syndrome of Swyer can be easily identified based on general examination (body sex characteristics, breast development, weight, height, etc.), pelvic exam, genetic analysis, ultrasound and hormonal blood tests.

In time diagnosis is essential for several reasons:

  • Adequate hormone replacement therapy,
  • Prevention of ovarian tumors (cancerous or benign),
  • Prevention of osteoporosis,
  • Development of future possible reproduction plans.

Swyer syndrome – complications

  • Absence of breast development,
  • Absence of menstrual cycles,
  • Infertility,
  • Osteoporosis,
  • Ovarian tumors (benign or cancerous).

Swyer syndrome – treatment

Treatment complex include psychological counseling, hormonal therapy and surgical removal of not developed ovaries.

Assisted reproductive technologies can offer few solutions including donated oocytes for IVF (in vitro fertilization) or intra-cytoplasmic injection (ICSI).


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