Overview

Turner syndrome is a genetic condition that affects females and is characterized by the complete or partial absence of one of the X chromosomes. It occurs in approximately 1 in 2,500 live female births. Individuals with Turner syndrome often experience short stature, delayed puberty, infertility, and certain physical features such as a webbed neck or low-set ears. While the condition can present with a variety of features, intellectual development is usually normal. Early diagnosis and management are essential to address medical complications and promote healthy development.

Causes

Turner syndrome is caused by a genetic abnormality involving the X chromosome:

• Monosomy X: The most common cause, where an entire X chromosome is missing in all cells (45,X karyotype).
• Mosaicism: Some individuals have a mixture of cells, some with the typical two sex chromosomes and others with only one X chromosome (45,X/46,XX).
• Structural abnormalities: In some cases, one X chromosome may be partially missing or have structural changes, such as a ring chromosome or isochromosome.

Turner syndrome is usually not inherited and occurs due to random errors during cell division in early fetal development.

Symptoms

The symptoms of Turner syndrome vary widely, and not all individuals will have every feature. Common signs and symptoms include:

• Short stature: Most noticeable feature, with adult height significantly below average without treatment.
• Delayed puberty: Lack of typical development of breasts and menstruation due to ovarian failure.
• Infertility: Most individuals with Turner syndrome are infertile due to nonfunctioning ovaries.
• Physical features: Webbed neck, low-set ears, broad chest with widely spaced nipples, and swelling of hands and feet (especially at birth).
• Heart defects: Common abnormalities include coarctation of the aorta and bicuspid aortic valve.
• Kidney abnormalities: Structural differences in kidneys can increase the risk of hypertension or infections.
• Learning difficulties: Normal intelligence is typical, but some may experience problems with spatial reasoning or mathematics.
• Hearing problems: Increased risk of recurrent ear infections and gradual hearing loss.
• Eye issues: Problems like drooping eyelids or farsightedness may occur.
• Skin abnormalities: Increased likelihood of moles or skin nevi.

Diagnosis

Turner syndrome can be diagnosed at different stages of life, including prenatal, infancy, or during childhood:

• Prenatal diagnosis: Noninvasive prenatal testing (NIPT), chorionic villus sampling (CVS), or amniocentesis can identify chromosomal abnormalities before birth.
• Physical examination: Characteristic physical features may prompt further testing in newborns or children with short stature or delayed puberty.
• Karyotype analysis: The most definitive test that examines the chromosomal makeup and confirms the absence or abnormality of one X chromosome.
• Genetic testing: More detailed analysis may reveal structural abnormalities or mosaicism.
• Imaging tests: Echocardiogram and kidney ultrasound are commonly used to detect associated heart and kidney issues.
• Hormone tests: Blood tests may reveal low levels of sex hormones due to ovarian dysfunction.

Treatment

There is no cure for Turner syndrome, but various treatments can help manage symptoms and improve quality of life:

• Growth hormone therapy: Regular injections can increase final adult height when started in early childhood.
• Estrogen replacement therapy: Initiated around puberty to promote development of secondary sexual characteristics and regulate menstrual cycles.
• Fertility options: Assisted reproductive technologies, such as in vitro fertilization (IVF) with donor eggs, may offer pregnancy possibilities for some individuals.
• Regular screenings: Monitoring for heart, kidney, thyroid, and hearing problems to allow early intervention.
• Educational support: Assistance with learning difficulties, particularly in math and spatial skills, if needed.
• Psychological support: Counseling or support groups can help address emotional and social challenges.
• Healthy lifestyle: Encouraging physical activity, a balanced diet, and regular medical care helps prevent complications such as osteoporosis or hypertension.

Prognosis

The prognosis for individuals with Turner syndrome has improved significantly with early diagnosis and appropriate management. With medical care and support, most girls with Turner syndrome lead healthy and fulfilling lives. Growth hormone and hormone replacement therapies can help address physical development, and modern healthcare allows monitoring and treatment of associated health risks.

While infertility is common, reproductive options are available, and life expectancy is near normal with good management. Regular follow-up with healthcare providers ensures early detection of complications and promotes overall well-being. Education, social support, and personalized care plans are essential in helping individuals with Turner syndrome achieve their fullest potential.