Notes from NEET topper
Turner’s syndrome
Definition:
Turner syndrome, also known as 45,X syndrome, is a chromosomal disorder that affects females. It is characterized by the complete or partial absence of one of the X chromosomes, resulting in a variety of physical and developmental differences.
Causes:
Turner syndrome occurs due to a random error during the formation of egg cells. Instead of the typical XX chromosome configuration in females, individuals with this syndrome have a 45,X karyotype, where one of the X chromosomes is either missing or structurally altered. This error typically happens during conception and is not inherited from parents.
Characteristics and Clinical Features:
1. Short Stature:
Short stature is one of the most common and noticeable features of Turner syndrome. Affected individuals tend to be significantly shorter than their peers.
2. Physical Characteristics:
Webbed neck: Some individuals may have a webbed appearance of the neck due to extra skin folds.
Low-set ears.
Swelling of the hands and feet (lymphedema) in infancy.
Broad chest with widely spaced nipples.
Reproductive anomalies: Most individuals with Turner syndrome have underdeveloped or absent ovaries, leading to infertility.
3. Cardiovascular Issues:
Congenital heart defects may occur in some individuals, particularly coarctation of the aorta.
4. Kidney Abnormalities:
Some individuals may have kidney abnormalities.
5. Hormonal Imbalance:
Reduced production of sex hormones (estrogen) leads to delayed or absent puberty.
This can result in the lack of secondary sexual characteristics like breast development and menstruation.
6. Learning and Cognitive Features:
Normal intelligence, but there may be specific learning disabilities, particularly in mathematics.
7. Hearing Loss:
Some individuals may experience hearing loss, especially in the higher frequencies.
Diagnosis:
Turner syndrome can be diagnosed through karyotype analysis, which involves examining a blood sample for chromosomal abnormalities. Prenatal diagnosis can also be performed through chorionic villus sampling or amniocentesis.
Management and Treatment:
Hormone replacement therapy (estrogen replacement) is usually initiated at the appropriate age to induce puberty, develop secondary sexual characteristics, and support bone health.
Growth hormone therapy may be considered to improve final adult height.
Cardiac monitoring is important to detect and manage any heart defects.
Regular check-ups and screenings for kidney and hearing issues.
Life Expectancy:
With appropriate medical care and support, individuals with Turner syndrome can lead healthy lives. Life expectancy is generally normal.
Genetic Counseling:
Genetic counseling may be recommended for individuals with Turner syndrome who are planning to have children, as they have a higher risk of having daughters with Turner syndrome.