Turner syndrome (Year of the Zebra)

Summary

Turner syndrome is a chromosomal disorder affecting females, caused by the partial or complete absence of one X chromosome, resulting in a 45X karyotype. This condition leads to a range of physical and developmental challenges, including short stature, streak ovaries, heart defects, and kidney abnormalities. Treatment often involves growth hormone therapy and sex hormone replacement to aid physical development and fertility. The syndrome can also present with symptoms like neck webbing and limb abnormalities. While some individuals may have mosaic forms with varying effects, Turner syndrome is commonly diagnosed through karyotype analysis, and early intervention can help manage symptoms.

Takeaways

• 😀 Turner syndrome is a chromosomal disorder that affects females, caused by the absence of one X chromosome, either completely or partially.
• 😀 The typical chromosomal pattern for Turner syndrome is 45X, meaning the individual has only 45 chromosomes instead of the usual 46.
• 😀 Turner syndrome can result from non-disjunction during meiosis, where the X chromosomes fail to separate correctly during cell division.
• 😀 There are three primary types of Turner syndrome: monosomy (45X), mosaicism (46XX/45X), and partial X deletion.
• 😀 Common physical characteristics of Turner syndrome include short stature, neck webbing, and swelling in the hands and feet (lymphedema).
• 😀 Individuals with Turner syndrome may also experience congenital heart defects like coarctation of the aorta and bicuspid aortic valve.
• 😀 Kidney abnormalities, such as horseshoe kidney, are common in those with Turner syndrome, increasing the risk of urinary tract infections.
• 😀 Ovaries in people with Turner syndrome are underdeveloped, leading to streak ovaries, infertility, and primary amenorrhea (lack of menstruation).
• 😀 Diagnosis of Turner syndrome is typically made via karyotype analysis, but ultrasounds and blood tests can help identify associated health issues.
• 😀 Treatment for Turner syndrome often involves growth hormone therapy in childhood and estrogen replacement therapy during adolescence to induce puberty.
• 😀 Many women with Turner syndrome are infertile, but assisted reproductive techniques like in vitro fertilization (IVF) can help some conceive.

Q & A

What is Turner syndrome?

Turner syndrome is a chromosomal disorder that affects females, where one X chromosome is either completely or partially absent. This leads to a variety of developmental and physical issues.

Who first described Turner syndrome?

Turner syndrome was first described by Henry Turner, hence the name of the condition.

How are human chromosomes typically arranged?

Humans typically have 46 chromosomes, arranged in 23 pairs. Each pair consists of one chromosome from each parent. The sex chromosomes determine biological sex, with females having two X chromosomes and males having one X and one Y chromosome.

What is non-disjunction and how does it relate to Turner syndrome?

Non-disjunction is the failure of chromosomes to separate properly during cell division, which can result in cells with an extra chromosome or missing one. In Turner syndrome, non-disjunction of the sex chromosomes can lead to the absence of one X chromosome, resulting in a 45X karyotype.

What is mosaicism in the context of Turner syndrome?

Mosaicism in Turner syndrome occurs when some cells in the body have the 45X karyotype (one X chromosome missing), while others have the normal 46XX karyotype. This happens due to non-disjunction during mitosis after conception.

What are the main health issues associated with Turner syndrome?

Individuals with Turner syndrome are at higher risk for cardiovascular issues like coarctation of the aorta and bicuspid aortic valve, kidney abnormalities such as horseshoe kidney, lymphatic and skeletal problems, and endocrine disorders like hypothyroidism and type 2 diabetes.

How does Turner syndrome affect the reproductive system?

Turner syndrome affects the female reproductive system by causing the ovaries to become non-functional, leading to streak ovaries, early menopause, and infertility. The lack of functional ovaries leads to low estrogen levels and associated secondary sexual characteristics.

What are some common physical features of individuals with Turner syndrome?

Common physical features of Turner syndrome include short stature, broad chest with widely spaced nipples, low-set ears, outward-turning elbows, neck webbing, and swelling of the hands and feet at birth.

How is Turner syndrome diagnosed?

Turner syndrome is diagnosed through karyotype analysis, which identifies the number and structure of chromosomes. It can be diagnosed prenatally through procedures like chorionic villus sampling or amniocentesis.

What treatments are available for Turner syndrome?

Treatment for Turner syndrome typically involves growth hormone therapy during childhood to promote height, and sex hormone replacement therapy starting in adolescence to support the development of secondary sexual characteristics. For some, in vitro fertilization may help achieve pregnancy despite infertility.