TURNER SYNDROME

Turner syndrome is a rare genetic disorder exclusive to females, causing various issues from short stature to heart abnormalities. It may go undiagnosed until adolescence or early adulthood due to its mild symptoms.

The condition stems from the absence of specific genes typically found on the X chromosome, of which females have two copies while males have one X and one Y chromosome.

Causes of Turner syndrome

Different scenarios are causing Turner syndrome:

1. Monosomy: The complete absence of one X chromosome in all cells due to an issue with the egg or sperm from one of the parents.
2. Mosaicism: During early fetal development, incorrect cell division results in some cells having two complete copies of the X chromosome while others have only one.
3. X chromosome abnormalities: Cells possess one complete and one abnormal or missing copy of the X chromosome.
4. Y chromosome material: In rare instances, some cells have one X chromosome and others have one X chromosome along with some Y chromosome material. Despite developing as females biologically, the presence of Y chromosome material elevates the risk of a cancer type called gonadoblastoma.

Approximately 70,000 women and girls in the United States are affected by Turner syndrome. Research indicates that nearly 99% of babies missing an X chromosome are miscarried, but in about 1% of cases, these babies are born with the syndrome.

Symptoms

The signs of this syndrome may become apparent even before birth, offering parents early indications that their baby might have the condition. During prenatal ultrasounds, abnormalities like heart and kidney issues or fluid buildup may be detected in affected fetuses.

Furthermore, a simple DNA test utilizing a blood sample from the mother can screen for this syndrome before the baby is born.

At birth or in infancy, girls with Turner syndrome may exhibit various physical characteristics indicating the condition. These can include:

1. Swollen hands and feet or below-average height at birth.
2. Distinctive physical features such as:
   • A broad or web-like neck with additional folds of skin.
   • A small or receding lower jaw and a high, narrow palate.
   • Low-set ears and a hairline that sits lower than usual.
   • A broad chest with widely spaced nipples.
   • Arms that turn outward at the elbows.
   • Short fingers and toes, along with narrow fingernails and toenails.
   • Delayed growth.
   • Heart defects.
   • Eyelids that turn downward.
   • Short roots of teeth.
   • Abnormalities in the kidneys.
   • An increased number of moles on the skin.

As affected females age, symptoms may persist throughout their lives, potentially including:

1. Lack of expected growth spurts during childhood.
2. Shorter stature compared to the anticipated height based on parental height.
3. Learning difficulties.
4. Inability to undergo normal puberty due to ovarian failure.
5. Absence of menstrual cycles.
6. Infertility.

Complications of Turner Syndrome

From birth and throughout life,this syndrome can be associated with various health conditions, including:

1. Heart problems stemming from its physical structure.
2. Increased risk of diabetes and high blood pressure.
3. Hearing impairment.
4. Kidney issues, which can elevate the risk of high blood pressure and urinary tract infections.
5. Immune disorders such as diabetes, inflammatory bowel disease, and hypothyroidism, where the thyroid gland fails to produce enough hormone for proper bodily function.
6. Gastrointestinal bleeding.
7. Dental and vision impairments.
8. Scoliosis, characterized by a curvature of the spine, and osteoporosis, leading to fragile bones.
9. Learning disabilities.
10. Mental health challenges.
11. Obesity.
12. Difficulty conceiving in women with Turner syndrome, and if pregnancy occurs, issues like high blood pressure and gestational diabetes may arise.

Diagnosis

If abnormalities are detected during prenatal ultrasound, your doctor may recommend examining the baby’s chromosomes through a process called karyotyping. This involves aligning and comparing chromosomes. To obtain samples, various methods may be used:

1. Amniocentesis: Extraction of amniotic fluid surrounding the baby in the uterus.
2. Blood sample: Testing to determine if the baby is missing all or part of an X chromosome.
3. Chorionic villus sampling (CVS): Removal of tissue samples from a portion of the placenta, typically performed around 10-12 weeks of pregnancy.
4. Cheek scraping or skin sample: Cells scraped from the inside of the cheek (buccal smear) or a sample of skin cells may be used for testing.

If a diagnosis is not made before or at birth, additional laboratory tests checking hormones, thyroid function, and blood sugar levels can aid in diagnosis.

Due to the potential complications associated with Turner syndrome, doctors often recommend tests for kidney function, heart health, and hearing.

Treatment for Turner Syndrome

Medical care for this syndrome typically involves a multidisciplinary team of specialists tailored to meet each individual’s specific needs due to the wide variation in cases.

While there’s no cure, most girls with Turner syndrome undergo similar main therapies during childhood and adolescence, including:

1. Growth hormone therapy: Administered via injections a few times a week to maximize height potential.
2. Estrogen therapy: Initiated around the onset of puberty until reaching the average age of menopause. This hormone treatment aids in growth and facilitates adult sexual development.

Additionally, almost all women with Turner syndrome require fertility treatments to achieve pregnancy. However, pregnancy comes with associated health risks, which should be discussed thoroughly with a doctor for those with Turner syndrome.

Sources

1. National Institutes of Health-U.S. National Library of Medicine Genetics Home Reference: “Turner Syndrome,” “X chromosome.”
2. Turner Syndrome Society of the United States: “About Turner Syndrome.”
3. Medscape: “Turner Syndrome.”
4. Mayo Clinic: “Turner Syndrome.”
5. National Organization for Rare Disorders: “Turner Syndrome.”
6. American Thyroid Association: “Hypothyroidism.”
7. American Family Physician: “Turner Syndrome: Diagnosis and Management.”