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Klinefelter and Turner Syndrome

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Klinefelter and Turner Syndrome

Chromosomes hold vital genetic information in the form of genes, and they exist throughout the body in the cells. As you may know, humans have 23 chromosomes, and typically, a person having either XX chromosomes (female) or XY chromosomes (male) determines their sex. However, some syndromes can affect these sex chromosomes, causing many issues for those involved, known as atypical sex chromosome patterns (Klinefelter and Turner syndrome).

Atypical sex chromosome patterns: Klinefelter and Turner syndromes

Sex chromosome patterns are atypical when they deviate from the typical XX/XY formations, which give us male or female characteristics.

Two prominent examples of this are Klinefelter’s syndrome and Turner’s syndrome.

Males with Klinefelter’s syndrome have an extra X chromosome (XXY), i.e., they develop small infertile testes, a slim frame, and enlarged breasts.

Females with Turner’s syndrome lack an X chromosome, leading to underdeveloped ovaries and infertility.

What is Klinefelter’s syndrome?

Klinefelter’s syndrome is when biologically male people (anatomically appear male) have an extra X chromosome, making their chromosome pattern XXY.

Although 10% of cases are diagnosed prenatally, two-thirds of people with the condition are unaware they have Klinefelter’s syndrome. In such cases, diagnosis is often made due to another health condition.

Klinefelter and Turner Syndrome Klinefelter's syndrome males StudySmarterNHS England states that Klinefelter’s syndrome affects around 1 in 660 males

Physical characteristics

  • Reduced body hair.

  • Slim physique.

  • Tall.

  • Gynecomastia: breast development at puberty.

  • Softening of body contours.

  • Broad hips.

  • Long limbs.

  • Underdeveloped genitals.

  • Coordination problems.

  • Clumsiness.

  • More susceptible to typically female illnesses such as breast cancer.

Psychological and behavioural characteristics

  • Poorly developed reading and language skills.

  • Passivity.

  • Shyness.

  • Lack of interest in sexual activity, infertility.

  • Inability to cope with stress.

  • Problems with executive functions such as memory and problem-solving.

What is Turner’s syndrome?

Turner’s syndrome occurs in biological females who lack an X chromosome, i.e., Turner’s syndrome patients have 45 chromosomes rather than the usual 46.

Klinefelter and Turner Syndrome Turner's syndrome females StudySmarterNHS England states that Turner’s syndrome affects around 1 in every 2000 females

Physical characteristics

  • Amenorrhoea: a lack of menstrual cycle due to their ovaries failing to develop and being sterile as a result.

  • Lack of breast development leaving them with a broad ‘shield’ chest.

  • Low set ears.

  • ‘Webbed neck’ (an area of folded skin that goes from the ears to the neck)

  • Low waist-to-hip ratio. Hips are not much bigger than the waist.

  • Physically immature, appearing prepubescent.

  • Shortness.

Psychological and behavioural characteristics

  • Above-average reading ability.

  • Reduced spatial, mathematical, and visual memory skills.

  • Socially immaturity.

  • Difficulty fitting in.

Evaluation of the Klinefelter and Turner syndromes

How would we evaluate the atypical sex chromosome patterns? Let’s look at some of their strengths and weaknesses.

Strengths

First, let’s examine some of the strengths.

Contribution to the nature-nurture debate

The existence of genetically atypical individuals means we can determine whether gender differences have a genetic basis. We can compare these individuals with chromosome-typical people. If we see psychological or physical differences between the two groups, we can infer these result from genetic differences. Thus, gender development has a biological basis, and ‘nature’ has a powerful effect on gender-related psychology and behaviour.

Practical applications

Research into atypical sex chromosome patterns is likely to lead to earlier and accurate diagnoses of both Turner’s and Klinefelter’s syndrome, meaning that positive outcomes are more likely for patients.

Herlihy et al. (2011) studied 87 Australian individuals with Klinefelter’s syndrome. They found that those treated from a young age had significant benefits compared to those diagnosed in adulthood, such as better treatment and services to help them.

Weaknesses

Here are some of the weaknesses as well.

Environmental explanations

The differences between people with atypical vs typical chromosome patterns are not causal. Therefore, other factors could influence this, such as the environment or social influences.

For example, the social immaturity cited as a symptom of Turner’s syndrome could result from women with the condition being treated as younger than they are due to their immature appearance. If they look youthful, this could lead to educational problems as teachers and parents may treat them as younger and less educated than others.

Therefore, it is wrong to assume that all the symptoms associated with both syndromes are purely a result of atypical chromosome patterns, as the environment could influence them.

Unusual sample

As we have previously discussed, the physical differences in those with Turner’s syndrome and Klinefelter’s syndrome may cause others to treat them differently, leading to psychological and social differences. This highlights the rarity of people with atypical chromosome patterns, making it difficult to generalise the results of studies using them in their sample.

What is typical?

Diagnosis of both syndromes assumes ‘typical’ gender behaviours. For example, stating that shy men are atypical suggests that confidence is a male characteristic, upholding societal views of a ‘typical male’. These assumptions could be problematic because the definitions of both syndromes use socially established gender norms to diagnose people with medical conditions.

Klinefelter and Turner Syndrome - Key takeaways

  • Sex chromosome patterns are atypical when they deviate from the typical XX/XY formations, which give us male or female characteristics.

  • Males with Klinefelter’s syndrome have an extra X chromosome (XXY), i.e., they develop small infertile testes, a slim frame, and enlarged breasts.

  • Females with Turner’s syndrome lack an X chromosome, leading to underdeveloped ovaries and infertility.

  • Studying these syndromes can help to determine the nature/nurture debate.

  • Studies of Klinefelter’s syndrome and Turner’s syndrome can help treat the conditions more effectively.

  • There might be environmental influences on gender development in people with atypical chromosome patterns that biologists fail to consider.

  • Definitions of atypical behaviours rely on gendered notions of normal behaviour for each gender.

  • We may not be able to generalise findings from studies of both syndromes due to the unique nature of the samples.

Frequently Asked Questions about Klinefelter and Turner Syndrome

Klinefelter’s syndrome is where males have an extra X chromosome: XXY. Turner’s syndrome is where females lack an X chromosome.

Turner’s syndrome is where a female has a missing or altered X chromosome. So, they will have an X chromosome instead of the usual XX.

Causes can vary. Typically, however, it is due to the chromosomes being affected during the formation of reproductive cells (sperm and egg). For instance, nondisjunction prevents the proper distribution of X chromosomes. 

The chromosome abnormality in the Klinefelter syndrome is an additional X chromosome, so males have XXY chromosomes instead of the typical XY.

The Klinefelter syndrome is not an inherited disorder, so it is neither recessive nor dominant.

Final Klinefelter and Turner Syndrome Quiz

Question

What is an atypical sex chromosome pattern?

Show answer

Answer

Sex chromosome patterns are atypical when they deviate from the typical XX/XY formations, which give us male or female characteristics. 

Show question

Question

What is Klinefelter’s syndrome?

Show answer

Answer

Males with Klinefelter’s syndrome have an extra X chromosome (XXY), i.e., they develop small infertile testes, a slim frame, and enlarged breasts.

Show question

Question

What is the chromosome pattern for people with Klinefelter’s syndrome? 


Show answer

Answer

XXY

Show question

Question

What is Turner’s syndrome?

Show answer

Answer

Turner’s syndrome is when females lack an X chromosome, leading to a lack of breast development and infertility.

Show question

Question

What is the chromosome pattern for people with Turner’s syndrome? 

Show answer

Answer

X

Show question

Question

How many chromosomes does a person with Turner’s syndrome have?


Show answer

Answer

45.

Show question

Question

What is a physical characteristic of Klinefelter’s syndrome? 


Show answer

Answer

Overdeveloped breasts.

Show question

Question

What is a psychological characteristic of Klinefelter’s syndrome?


Show answer

Answer

Passivity.

Show question

Question

 What is a physical characteristic of Turner’s syndrome?

Show answer

Answer

Under-developed breasts.

Show question

Question

 What is a psychological characteristic of Turner’s syndrome?

Show answer

Answer

Above-average reading ability.

Show question

Question

Which side of the nature-nurture debate do the symptoms of Turner’s syndrome fall on? 

Show answer

Answer

The suggestion that chromosome patterns influence behavioural and physical characteristics suggests they fall on the nature side. 

Show question

Question

What is a practical application of investigating these conditions?

Show answer

Answer

We can diagnose and treat these conditions early and effectively by investigating them.

Show question

Question

What is a criticism of research into Turner’s syndrome and Klinefelter’s syndrome?

Show answer

Answer

Diagnosis of both syndromes assumes ‘typical’ gender behaviours. For example, stating that shy men are atypical suggests that confidence is a male characteristic, upholding societal views of a ‘typical male’. These assumptions could be problematic because the definitions of both syndromes use socially established gender norms to diagnose people with medical conditions.

Show question

Question

What is one environmental explanation for the behavioural characteristics associated with Turner’s syndrome?

Show answer

Answer

The social immaturity cited as a symptom of Turner’s syndrome could result from women with the condition being treated as younger than they are due to their youthful appearance. Looking young could lead to educational problems as teachers and parents may treat them as more immature and less educated than others. 

Show question

Question

Why do researchers state it is hard to generalise the 

findings of studies into Klinefelter’s and Turner’s syndrome? 

Show answer

Answer

Because the sample is very unusual compared to the 

general population.

Show question

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