By Momina Shehzadi | BS Zoology Graduate, Pakistan In this article, we will learn Fungi - Morphology, Reproduction, Physiology and Importance - in simple words with diagram. This topic is very important for BS Zoology and Microbiology students. Fungi are found everywhere around us. They are present in soil, in water, in air, on dead plants, on dead animals, on our food, on our skin and even inside our body. When bread becomes old, green or black spots appear on it. These spots are fungi. When we see mushroom growing after rain, that is also a fungus. When yeast is used to make bread soft, that is also a fungus. Fungi are very different from bacteria and plants. They are eukaryotic organisms. It means their cells have a true nucleus and other membrane bound organelles. They do not have chlorophyll, so they cannot make their own food like plants. They get their food from other living or dead things. That is why they are called heterotrophic organisms. The study of fungi is called mycolog...
By Momina Shehzadi | BS Zoology Graduate, Pakistan
In this article, we will learn about Turner Syndrome - 45,X - in simple words with karyotype, causes, symptoms, diagnosis and treatment. This topic is very important for BS Zoology, Genetics, and MBBS students.
In this article, we will learn about Turner Syndrome - 45,X - in simple words with karyotype, causes, symptoms, diagnosis and treatment. This topic is very important for BS Zoology, Genetics, and MBBS students.
What is Turner Syndrome?
Turner Syndrome is a genetic disorder that affects only females. It occurs when one of the X chromosomes is completely or partially missing. In a normal female, there are 46 chromosomes including two X chromosomes (46,XX). But in Turner Syndrome, there are only 45 chromosomes with a single X chromosome (45,X). This condition was first described by Dr. Henry Turner in 1938.
This syndrome is not very rare. According to medical data, it affects about 1 in 2,500 newborn girls worldwide. Because one X chromosome is missing, the development of ovaries and physical growth is affected from birth.
It is important to understand that Turner Syndrome is not caused by anything the parents did. It is a random error that happens during the formation of reproductive cells.
Karyotype of Turner Syndrome
To understand Turner Syndrome, we must understand the karyotype.
The normal karyotype of a human female is 46,XX. This means 44 autosomes plus two sex chromosomes XX.
The karyotype of a girl with Turner Syndrome is 45,X. This means 44 autosomes plus only one X chromosome. The second sex chromosome is missing. This condition is called Monosomy.
There is another type called Mosaic Turner Syndrome. In this type, some cells of the body have 45,X and some cells have normal 46,XX. The mosaic karyotype is written as 45,X / 46,XX. The symptoms in mosaic type are usually milder than in complete monosomy.
This missing chromosome is the main reason for all the symptoms seen in Turner Syndrome.
Causes of Turner Syndrome
The main cause of Turner Syndrome is an error in cell division called nondisjunction.
Nondisjunction means that the chromosomes fail to separate properly during meiosis. Meiosis is the process that forms eggs and sperms. If nondisjunction happens during the formation of an egg or sperm, the resulting egg may have no X chromosome. When such an egg is fertilized by a normal sperm carrying an X chromosome, the baby will have only one X chromosome (45,X).
In most cases, about 70% to 80%, the single X chromosome comes from the mother. This means the paternal X chromosome is missing.
Turner Syndrome is not an inherited disorder. Parents who have one child with Turner Syndrome usually do not have a higher risk of having another child with the same condition. It is a random event that happens at the time of conception.
Signs and Symptoms of Turner Syndrome
The symptoms of Turner Syndrome can be different for each girl. Some symptoms are visible at birth, while others appear during childhood or puberty.
1. Symptoms at Birth and Infancy:
The most common signs at birth are swelling of the hands and feet, known as lymphedema. This happens due to abnormal development of the lymphatic system. Other signs include a webbed neck, which means extra skin folds on the sides of the neck, a low hairline at the back of the head, and low-set ears. Some babies also have a small jaw and a high, narrow roof of the mouth.
2. Symptoms in Childhood and Adulthood:
The most consistent feature of Turner Syndrome is short stature. Girls with Turner Syndrome are usually much shorter than average if they do not receive growth hormone treatment. The average adult height without treatment is about 4 feet 8 inches.
Another major symptom is ovarian failure. The ovaries do not develop normally and are replaced by streaks of fibrous tissue. Because of this, most girls do not enter puberty naturally. They do not develop breasts, and they do not get menstrual periods. They are also infertile, meaning they cannot become pregnant naturally, although pregnancy is possible with assisted reproductive technology using donor eggs.
Other health problems are also common. About 30% of girls have heart defects, especially coarctation of the aorta, which is narrowing of the main blood vessel from the heart. Kidney problems, high blood pressure, hearing loss, and thyroid problems like hypothyroidism are also more common. Some girls may also have learning difficulties, especially with spatial concepts and math, although intelligence is usually normal.
How is Turner Syndrome Diagnosed?
The diagnosis of Turner Syndrome is done by a test called karyotyping. Karyotyping is the study of chromosomes under a microscope.
If a doctor suspects Turner Syndrome based on physical features, a blood sample is taken. The chromosomes from the white blood cells are stained and examined. If only one X chromosome is seen, the diagnosis is confirmed.
Turner Syndrome can also be diagnosed before birth. If an ultrasound shows swelling or heart problems in a female fetus, the doctor may suggest amniocentesis. In this test, a small amount of amniotic fluid is tested to check the chromosomes of the baby.
Early diagnosis is very important because early treatment can improve growth and overall health.
Treatment and Management
There is no cure for Turner Syndrome because it is a chromosomal condition. However, the symptoms can be managed effectively with proper medical care.
1. Growth Hormone Therapy: To improve height, growth hormone injections are given. This treatment usually starts in early childhood, around 5 to 6 years of age. If started early, it can add several inches to the final adult height.
2. Estrogen Replacement Therapy: To induce puberty, estrogen and progesterone hormones are given. This therapy usually starts around 11 to 12 years of age. It helps in the development of breasts and other female characteristics and also helps in maintaining bone health and inducing menstrual cycles.
3. Regular Medical Monitoring:Girls with Turner Syndrome need regular checkups throughout their life. This includes heart checkups by a cardiologist, blood pressure monitoring, thyroid function tests, hearing tests, and kidney ultrasound. Early detection of any problem can prevent complications.
4. Psychological Support: Learning support and counseling can help girls cope with short stature and infertility issues. Many women with Turner Syndrome lead normal, healthy, and productive lives with proper support.
Conclusion
Turner Syndrome is a manageable genetic condition. Although it presents challenges related to growth and reproduction, early diagnosis and modern treatments allow affected girls to live a near-normal life. Awareness and timely medical care are the keys to better outcomes.
FAQs for Exam:
Q1: What is the karyotype of Turner Syndrome?
Ans: The karyotype is 45,X. Normal female is 46,XX. In Turner, one X chromosome is missing. Mosaic type is 45,X / 46,XX.
Q2: Does Turner Syndrome affect only females?
Ans: Yes, it affects only females because it is due to missing X chromosome. Males have XY, so they cannot have Turner Syndrome.
Q3: Is Turner Syndrome inherited from parents?
Ans: No, it is not inherited. It is a random error called nondisjunction during meiosis. Parents with normal chromosomes can have a child with Turner Syndrome.
Q4: Can a woman with Turner Syndrome become pregnant?
Ans: Most women are infertile due to streak ovaries. Natural pregnancy is very rare, but pregnancy is possible with donor egg IVF and medical care.
Written by Momina Shehzadi, BS Zoology Graduate from Pakistan.
Disclaimer: This article is for educational purposes only and is intended for Zoology and Medical students. It does not provide medical advice. Please consult a qualified healthcare professional for diagnosis and treatment.
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