118. Karyogram of an individual shows presence of 45 chromosomes (44+x) and one
sexchromosome is missing. The individual has a female appearance and dwarfism. Whichof the
following is the most probable condition associated with this individual?
(a) Down’s syndrome,
(b) Edward’s syndrome,
(c) Klienfelter’s syndrome,
(d) Turner’s syndrome

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Understanding Turner’s Syndrome: A Genetic Condition with Female Appearance and Dwarfism

Turner’s syndrome is a genetic disorder that affects females, and it is characterized by the presence of only one X chromosome instead of two. This condition leads to various physical and developmental features, including a female appearance, short stature (dwarfism), and several other health-related complications. In this article, we will explore Turner’s syndrome in detail, focusing on its genetic causes, symptoms, and how it is typically diagnosed.

What is Turner’s Syndrome?

Turner’s syndrome, also known as monosomy X, occurs when one of the two X chromosomes typically found in females is missing or partially deleted. This results in a total of 45 chromosomes instead of the typical 46 chromosomes. The missing sex chromosome is a hallmark of the condition, leading to various physical and developmental characteristics.

Key Genetic Characteristics of Turner’s Syndrome:

1. Karyotype with 45 Chromosomes: Individuals with Turner’s syndrome typically have a karyotype of 45, X (44 autosomal chromosomes and a single X chromosome). In some cases, the X chromosome is partially missing or may have structural abnormalities, but the condition is still associated with the absence of a second sex chromosome.

2. Female Appearance: Although females typically have two X chromosomes, individuals with Turner’s syndrome exhibit a female phenotype. This means they typically appear female, but they may have underdeveloped secondary sexual characteristics such as a lack of menstruation or non-functioning ovaries.

3. Dwarfism (Short Stature): One of the hallmark features of Turner’s syndrome is short stature. Individuals with Turner’s syndrome often have a significantly shorter height compared to their peers, with an average adult height of about 4’8″ (142 cm). Growth hormone therapy is sometimes used to help improve growth.

Symptoms and Characteristics of Turner’s Syndrome:

• Physical Characteristics:

  • Short stature (dwarfism)

  • Broad, webbed neck

  • Low-set ears

  • Puffy hands and feet

  • Shield-shaped chest with widely spaced nipples

  • Poorly developed ovaries leading to infertility or absent menstruation

• Health Issues:

  • Heart defects (such as bicuspid aortic valve)

  • Kidney abnormalities

  • Hearing loss

  • Learning difficulties (primarily in spatial reasoning and mathematics)

  • Thyroid problems and autoimmune disorders

• Developmental Delays: While individuals with Turner’s syndrome usually have normal intelligence, they may experience developmental delays, particularly in motor skills and spatial awareness. Social skills may also be affected, though these individuals often thrive with appropriate support and therapy.

Diagnosis of Turner’s Syndrome:

Turner’s syndrome is usually diagnosed through genetic testing. A karyotype analysis can reveal the presence of a single X chromosome (45,X), confirming the diagnosis. In some cases, a genetic mutation or abnormality in the X chromosome may be identified.

Differential Diagnosis:

It’s important to distinguish Turner’s syndrome from other genetic conditions that may present with similar features. Some common conditions that might be confused with Turner’s syndrome include:

• Down’s Syndrome: Caused by an extra copy of chromosome 21 (trisomy 21), Down’s syndrome presents with developmental delays, characteristic facial features, and intellectual disabilities. However, individuals with Down’s syndrome usually have 47 chromosomes, not 45.

• Edwards Syndrome: Edwards syndrome is caused by trisomy 18, where there is an extra chromosome 18. It is associated with severe developmental issues, physical malformations, and a very short life expectancy.

• Klinefelter’s Syndrome: Klinefelter’s syndrome affects males who have an extra X chromosome (47, XXY). This results in male physical characteristics, but with some features such as infertility, breast enlargement, and lower testosterone levels.

• Turner’s Syndrome: As explained earlier, Turner’s syndrome involves a missing or incomplete X chromosome and is characterized by female appearance, dwarfism, and other health issues, making it the most probable diagnosis in this case.

The Correct Diagnosis:

Given the presence of 45 chromosomes (44 autosomal chromosomes + 1 X chromosome), the individual with female appearance and dwarfism most likely has:

(d) Turner’s syndrome.

Treatment and Management:

While there is no cure for Turner’s syndrome, various treatments are available to manage the symptoms and improve quality of life. These treatments include:

• Growth hormone therapy: To help increase height during childhood.

• Estrogen replacement therapy: To induce puberty and develop secondary sexual characteristics.

• Cardiac care: To manage heart-related issues, which are common in individuals with Turner’s syndrome.

• Fertility treatments: While most individuals with Turner’s syndrome are infertile, some may benefit from assisted reproductive technologies.

Conclusion:

Turner’s syndrome is a genetic condition that results in the loss of a sex chromosome, leading to various physical, developmental, and health-related challenges. Despite these challenges, individuals with Turner’s syndrome can lead fulfilling lives with the proper medical care and support. Recognizing the genetic causes and symptoms of Turner’s syndrome is critical for early diagnosis and intervention.