Turner syndrome is a congenital sex chromosome anomaly that occurs exclusively in females. It arises when one of the individual's two sex chromosomes (the X chromosome) is completely or partially missing. Normally, females have two X chromosomes, whereas individuals with Turner syndrome are missing one of these chromosomes (usually 45,X). This condition occurs directly due to differences in the genetic makeup and can be detected before or after birth using various methods. Turner syndrome occurs by chance and is not hereditary in most cases.
Turner syndrome is usually diagnosed through chromosome analysis. It may present with different clinical pictures in different individuals, and therefore some people are diagnosed at an early age, while others receive a diagnosis during adolescence or adulthood. Early diagnosis is of great importance in terms of improving the individual's quality of life with appropriate medical support. Although individuals with Turner syndrome require versatile medical follow-up and support throughout their lives, he can live as successful individuals in education, social life, and professional fields.
What Causes Turner Syndrome?
Turner syndrome occurs as a result of a genetic chromosome anomaly. Normally, female individuals have two X sex chromosomes (XX), but in Turner syndrome, one of these chromosomes may be completely missing (monosomy 45,X), structurally damaged, or present in a mosaic structure (for example, 45,X/46,XX). This genetic difference occurs due to errors in cell division during fertilization or in the early embryonic development stage.
This chromosomal deficiency occurs randomly; meaning it is usually not inherited and does not originate from the genetic makeup of the mother or father. The genetic differences caused by Turner syndrome can affect the development of many organs and systems in the body. However, it cannot be predicted in advance which exact cell division error will lead to which clinical picture. Therefore, Turner syndrome is a genetic condition too complex to be explained by a single cause-and-effect relationship.
What Are the Symptoms of Turner Syndrome?
The symptoms of Turner syndrome can vary greatly from person to person; while some individuals are diagnosed with prominent physical findings, in others these symptoms may be mild, and the diagnosis is only made in adolescence or adulthood. Symptoms may be noticed from birth or may appear during the developmental process.
The most common symptoms are:
Short stature: A slowdown in growth rate is observed during childhood, and height growth is limited in adolescence.
Delay or absence of puberty: Due to ovarian failure, estrogen production drops; which can cause puberty signs such as breast development and menstruation to be delayed or never begin.
Infertility: Because the ovaries do not develop sufficiently, natural pregnancy is usually not possible.
Webbed neck (thickening of the skin on the neck): A broad, webbed skin structure may be seen in the nape area.
Cardiovascular system anomalies: Congenital heart diseases, especially coarctation of the aorta, are common.
Thyroid diseases: Autoimmune thyroid diseases such as Hashimoto's thyroiditis are more common.
Learning disabilities: Intelligence level is generally normal, but difficulties may be experienced, especially in mathematics, navigation, and visuospatial skills.
Swelling in hands and feet: Edema in the hands and ankles may be observed, especially during infancy.
The course of Turner syndrome may show individual differences. Therefore, it is important to establish a personalized follow-up and treatment plan after diagnosis.
What Are the Types of Turner Syndrome?
Although Turner syndrome appears to be a single-type genetic disorder, it is actually a syndrome that can present with different genetic variants. These differences can affect the individual's clinical picture and treatment process. The types of Turner syndrome are basically classified according to the structure of the deficiency or abnormality in the X chromosome. The main types of Turner syndrome are explained in detail below:
1. Classical Turner Syndrome (45,X Monosomy)
This type is the most common and distinct form of Turner syndrome. There is only one X chromosome in the cells, and the other X chromosome is completely absent. In this case, the individual's chromosome arrangement is 45,X. This form is seen in approximately 45-50% of individuals with Turner syndrome.
In classical Turner syndrome, symptoms are usually more pronounced. Many systemic findings such as short stature, ovarian dysfunction, and heart and kidney abnormalities may accompany it. Since this genetic deficiency is present in all cells in these individuals, the clinical effects of the syndrome are observed more widely and clearly.
2. Mosaic Turner Syndrome (45,X/46,XX or 45,X/46,XY, etc.)
In mosaic Turner syndrome, some cells in the individual's body have 45,X (missing X chromosome), while other cells have a normal (46,XX) or another abnormal chromosome arrangement. In this form, both normal and abnormal cells coexist in the individual. This condition occurs due to an error in cell division occurring in the early stage of the embryo after fertilization.
The mosaic form is seen in approximately 30-40% of individuals with Turner syndrome. Clinical symptoms are usually milder compared to the classical form. For example, in some individuals, puberty signs such as menstruation or breast development may occur partially. The possibility of fertility may exist, albeit rarely. However, if these individuals have cells carrying a Y chromosome (e.g., 45,X/46,XY), he must be kept under special surveillance due to the risk of a tumor called gonadoblastoma in the future.
3. Structural X Chromosome Anomalies (Deletion, Isochromosome, Ring Chromosome)
In this type, the X chromosome is not completely lost, but contains structural impairments. The following sub-groups are examined under this heading:
a. Isochromosome Xq (46,X,i(Xq))
In this type, the short arm of the X chromosome is lost, while the long arm is duplicated twice. That is, while the individual has two long arms (Xq), the short arm (Xp) is missing. This causes some genes to be in double dose and some genes to be deficient. Symptoms such as ovarian failure and delayed puberty are common in individuals carrying an isochromosome.
b. Ring Chromosome X
The X chromosome has broken off at its ends and taken a ring shape. Different symptoms may occur depending on which regions of the chromosome are missing. A mosaic picture can also be encountered in this type.
c. Partial deletions (partial losses)
Certain regions of the X chromosome may be lost. Especially the loss of the Xp11.2 region is associated with short stature. Clinical symptoms in these types vary depending on which genetic information is lost.
4. Turner Syndrome Containing Y Chromosome (45,X/46,XY or other variants carrying Y material)
In some individuals with Turner syndrome, genetic material belonging to the Y chromosome can be detected within the mosaic structure. The external appearance of these individuals is female, but cells carrying the Y chromosome increase the risk of developing gonadoblastoma, which is a gonad (ovary) tumor. Therefore, surgical removal of the gonads is recommended for preventive purposes in such individuals.
The type of Turner syndrome can affect the health problems the individual may encounter, treatment options, and fertility potential. Therefore, after diagnosis, it is of great importance to determine which Turner variant the individual has through genetic tests such as karyotype analysis. Supportive treatment plans such as appropriate growth hormone, estrogen therapy, heart and kidney checks are established according to the type.
In conclusion, Turner syndrome is a complex syndrome that does not fit into a single mold and appears with different genetic variations. These variations can affect many areas from the individual's physical development to reproductive health, and from psychosocial status to quality of life. Therefore, it requires a versatile monitoring and treatment process that considers individual differences.
Can Turner Syndrome Be Diagnosed During Pregnancy?
Turner syndrome is a genetic disease that can be diagnosed during pregnancy. Thanks to the developing medical technologies today, the chromosome
structure of the baby in the womb can be examined in detail, so Turner syndrome can be detected in the prenatal period. The diagnosis process can be carried out with both invasive and non-invasive tests. Even if there is no family history, when risky findings are detected during routine pregnancy screenings, Turner syndrome can be suspected, and advanced tests for diagnosis can be performed.
Screening with Non-Invasive Prenatal Test (NIPT)
The non-invasive prenatal test (NIPT), which can be applied starting from approximately the 10th week of pregnancy, screens for possible chromosomal disorders in the baby by examining fetal DNA fragments circulating in the mother's blood. NIPT can also determine anomalies in sex chromosomes, especially Down syndrome (Trisomy 21). In this context, the risk of 45,X, which is Turner syndrome, can also be detected with a certain accuracy rate.
However, NIPT is a screening test; meaning it does not make a definitive diagnosis. If the test result shows a high risk for Turner syndrome, invasive diagnostic methods must be resorted to for a definitive diagnosis.
Invasive Prenatal Diagnostic Methods
The definitive diagnosis of Turner syndrome is made by invasive tests where the genetic structure of the baby's cells is directly examined. These tests are:
1. Chorionic Villus Sampling (CVS):
It can be performed between the 11th and 14th weeks of pregnancy. Chromosome analysis of the baby is performed using a small tissue sample taken from the placenta. It provides high accuracy in the diagnosis of chromosomal disorders such as Turner syndrome.
2. Amniocentesis:
It is usually applied between the 15th and 20th weeks of pregnancy. The baby's cells are examined with the sample taken from the amniotic fluid. It is one of the gold standard methods in the diagnosis of Turner syndrome.
3. Cordocentesis (Percutaneous Umbilical Cord Blood Sampling):
It is a method rarely resorted to after the 18th week. Genetic analysis is performed by taking a blood sample from the baby's umbilical cord. It can be used for late-stage diagnosis of Turner syndrome or in cases requiring more detailed examination.
Suspicion with Ultrasound Findings
Ultrasonography performed during pregnancy follow-up can enable the realization of some physical anomalies. The following ultrasound findings in fetuses with Turner syndrome may raise suspicion in terms of diagnosis:
- Increased nuchal thickness (nuchal translucency)
- Lymphatic fluid accumulation (cystic hygroma)
- Heart abnormalities (especially disorders in left heart development)
- Kidney structural disorders
- Fetal growth restriction
- Insufficient amniotic fluid (oligohydramnios)
- When such findings are seen, genetic counseling is recommended, and a referral is made to invasive tests to confirm the diagnosis.
Diagnosing Turner syndrome during pregnancy gives the family time and information in the process of making important decisions. With early diagnosis, the family is informed about the health status, needs, treatment, and follow-up plans of the baby to be born. At the same time, this information is of vital importance in terms of determining the center where birth will take place, organizing postpartum care, and planning necessary medical supports.
However, some families may face ethically and emotionally challenging decisions regarding continuing or terminating the pregnancy after diagnosis. Therefore, offering genetic counseling, psychological support, and multidisciplinary medical guidance to the family in the post-diagnosis process is of great importance.
Turner syndrome is a genetic disease that can be diagnosed during pregnancy. It can be detected in the early stages of pregnancy with both screening and diagnostic tests. The screening process starting with non-invasive prenatal tests is supported by definitive diagnostic methods such as CVS or amniocentesis if necessary. Thanks to early diagnosis, the family is offered an important advantage in terms of providing the best health conditions for the child to be born, making medical plans, and making informed decisions.
What Are the Diseases Seen in Persons with Turner Syndrome?
Turner syndrome is not only a chromosome deficiency but also a condition that can affect numerous organs and systems. Therefore, various health problems can be seen throughout the life of individuals with Turner syndrome. Although the type and severity of diseases vary from person to person, early diagnosis and treatment are possible with regular health checks. The diseases frequently encountered in individuals with Turner syndrome are systematically explained below:
1. Cardiovascular Diseases
Anomalies related to the cardiovascular system are encountered in approximately 30-50% of individuals with Turner syndrome. The most common ones are:
Bicuspid aortic valve (the aortic valve having two leaflets instead of the normally three leaflets)
Risk of aortic dissection (tear in the aorta vessel) – can become more serious especially if hypertension is present.
Hypertension (high blood pressure) – can be seen even at early ages and requires lifelong follow-up.
Since these heart conditions can lead to serious consequences, early diagnosis and regular cardiological checks are very important.
2. Endocrinological Problems
Turner syndrome directly affects the hormonal system:
Ovarian failure (gonadal dysgenesis): The production of female hormones decreases; this condition affects pubertal development and fertility.
Growth hormone deficiency: It is one of the main causes of short stature and is treatable.
Hypothyroidism: Autoimmune thyroid diseases, especially Hashimoto's thyroiditis, are common. This condition can manifest itself with symptoms such as fatigue, weight gain, and mood changes.
Insulin resistance and type 2 diabetes: The risk of metabolic syndrome increases, especially in adulthood.
3. Kidney Diseases
Kidney structural disorders are found in approximately 30% of individuals with Turner syndrome. The most common conditions:
- Horseshoe kidney (the lower ends of the two kidneys being fused)
- Unilateral renal agenesis (absence of one kidney)
- Narrowing or reflux in the urinary tract
These conditions can affect kidney functions and create a susceptibility to infections. Early diagnosis is possible with a routine kidney ultrasound.
4. Hearing Problems
Both conductive and sensorineural hearing loss can be seen in individuals with Turner syndrome:
- Susceptibility to middle ear infections is common during childhood.
- Hearing loss in older ages may occur due to inner ear-related (sensorineural) causes.
- Regular audiological evaluation is important.
5. Eye Problems
Some structural and functional disorders related to the eyes can be seen:
- Drooping of the eyelid (ptosis),
- Strabismus (crossed eyes),
- Refractive errors such as astigmatism and myopia,
- Color blindness is among the reported findings, albeit rarely.
6. Musculoskeletal System Problems
- Scoliosis (spinal curvature)
- Bone loss (osteoporosis): Bone density may decrease at an early age due to estrogen deficiency.
- Skeletal features such as short neck and low hairline may be prominent.
7. Digestive System and Liver Problems
Problems such as gallbladder stones and elevated liver enzymes can be encountered in some individuals with Turner syndrome. Although liver diseases usually have a mild course, regular follow-up is recommended.
8. Psychological and Neurological Problems
- Attention deficit and learning difficulties (especially in mathematical skills)
- Difficulties in social communication – emotional intelligence is generally good, but a lack of social skills may be seen in some individuals.
- Susceptibility to mood disorders such as anxiety and depression
9. Autoimmune Diseases
Susceptibility to diseases related to the immune system may increase in individuals with Turner syndrome:
Hashimoto's thyroiditis, celiac disease, inflammatory bowel diseases (rare).
Turner syndrome is not just a genetic difference, but a condition requiring versatile medical monitoring. It can lead to health problems in cardiological, endocrinological, nephrological, psychological, and many other fields. Therefore, individuals with Turner syndrome can lead a healthy life through lifelong monitoring with a multidisciplinary approach; early diagnosis, regular follow-up, and timely treatment.
How Is Turner Syndrome (TS) Diagnosed?
Since Turner syndrome (TS) is a genetic disease, the diagnosis process usually starts based on physical findings, but a definitive diagnosis is made only with genetic tests. Diagnosis can be made before birth (prenatal), at birth, or in later periods of life. Diagnosis is initiated either by suspecting physical symptoms or by detecting a chromosomal anomaly in routine screenings. The diagnostic process proceeds in several stages:
1. Physical Examination and Clinical Findings
If a newborn baby or an individual in childhood/adolescence has certain prominent features, Turner syndrome is suspected. Especially the following situations direct doctors to genetic evaluation:
- · Swelling in hands and feet at birth
- · Short stature (staying below the growth curve)
- · Delay in breast development or menstruation in puberty
- · Thickening of the neck skin (webbed neck), low hairline
- · Heart or kidney anomalies
When these symptoms are detected, genetic tests are requested, and the diagnosis is confirmed.
2. Karyotype Analysis (Chromosome Analysis) – Definitive Diagnosis
The gold standard method in diagnosing Turner syndrome is karyotype analysis. This test is performed by examining chromosomes obtained from cell samples such as blood or amniotic fluid under a microscope.
45,X: It is the most classical and common form (monosomy X).
Mosaic forms (e.g., 45,X/46,XX): Some cells of the individual have a missing X chromosome, while others have a normal structure.
Structural disorders: Anomalies such as deletions, ring chromosomes, or isochromosomes in the X chromosome can be detected with karyotype.
This test helps to establish a personalized follow-up and treatment plan by determining the type of Turner syndrome.
3. Prenatal Diagnosis
Turner syndrome can also be detected during pregnancy. This is especially recommended when anomalies are seen in ultrasound findings or in advanced maternal age pregnancies.
Non-Invasive Prenatal Test (NIPT): Risk assessment is performed by analyzing fetal DNA from the mother's blood.
Amniocentesis and Chorionic Villus Sampling (CVS): Applied at certain weeks of pregnancy to directly analyze the baby's chromosome structure.
4. Auxiliary Tests and Screening Tools
After diagnosis is made by karyotype analysis, the following tests can be performed to evaluate systemic problems that may accompany Turner syndrome:
Echocardiography: To evaluate heart structural anomalies
Renal ultrasonography: To detect kidney anomalies
Hormone tests: Ovarian function is evaluated by checking hormone levels such as estrogen, FSH, LH
Thyroid function tests: Important for the health of the thyroid gland
Hearing and vision tests: Eye and ear-related problems can be detected at an early stage
Since Turner syndrome is a genetically based disease, although the diagnostic process starts with clinical observations, it is confirmed by genetic tests such as karyotype analysis. Early diagnosis is of critical importance in terms of monitoring the individual's physical, hormonal, and psychological health and supporting it with appropriate interventions. Therefore, every individual suspected of having Turner syndrome must be evaluated in the field of genetic expertise.
How Is Turner Syndrome Treated?
Turner syndrome is a genetic condition that arises due to chromosome deficiency and is therefore not a completely curable disease. However, with early diagnosis and correct treatment, the quality of life of individuals with Turner syndrome can be significantly increased. The treatment approach is planned personally and generally covers many areas such as growth, puberty, fertility, cardiovascular health, hormone balance, and psychosocial support. Here are the basic approaches used in the treatment of Turner syndrome:
1. Growth Hormone Therapy
Growth retardation (short stature) is seen in the vast majority of individuals with Turner syndrome. Therefore, growth hormone therapy is applied during childhood.
It is usually started between the ages of 4–6 when a slowdown in the growth curve is noticed. It is done with recombinant human growth hormone (rGH) injected subcutaneously on a daily basis.
Goal: To promote height growth and ensure that the individual's adult height approaches normal. The success rate of growth hormone therapy is high, but it requires regular follow-up and dosage adjustments.
2. Estrogen and Progesterone Replacement Therapy (Hormone Therapy)
Estrogen production is low in individuals with Turner syndrome as a result of the ovaries not developing normally. This prevents pubertal development and the menstrual cycle.
It is started around the ages of 11–13, the period when the natural puberty process should begin. It is started with a low dose of estrogen, the dose is increased over time, and then progesterone therapy is added.
It aims to ensure breast development, uterine growth, and menstruation; at the same time protecting bone health. This hormone therapy usually continues until the age of menopause.
3. Fertility and Assisted Reproductive Methods
Natural pregnancy is very rare in Turner syndrome due to ovarian failure. However, different options are available for individuals who want to have children:
Egg donation: In vitro fertilization (IVF) treatment with an egg taken from another woman
Surrogacy: Can be recommended for individuals with heart disease or other health problems
Embryo freezing: Can be applied at an early age in individuals who have mosaic Turner syndrome and at least some ovarian reserve.
Cardiovascular health must be evaluated in detail in individuals with Turner syndrome planning pregnancy. They are in the high-risk pregnancy group due to the risk of aortic aneurysm.
4. Follow-up of Heart and Vascular Diseases
Congenital heart anomalies and hypertension are common in individuals with Turner syndrome. Therefore:
Regular follow-up of the heart should be done with imaging methods such as echocardiography and MRI. Blood pressure should be measured regularly. The development of hypertension can occur at an early age. Surgical intervention may be required in individuals carrying the risk of aortic aneurysm.
5. Thyroid and Metabolism Management
Autoimmune thyroid diseases (Hashimoto's thyroiditis) are particularly common in individuals with Turner syndrome. Thyroid function tests should be done regularly. If hypothyroidism is present, it is treated with levothyroxine. They carry the risk of metabolic syndrome in terms of insulin resistance, type 2 diabetes, and high cholesterol. Therefore, healthy nutrition, exercise, and weight control are important.
6. Psychological and Academic Support
Although the intelligence level is generally normal, learning difficulties (especially in mathematical and visuospatial skills) may occur in some individuals. In addition, the risk of social anxiety, lack of self-confidence, and depression may increase.
Learning support: Special education and counseling may be required in educational life.
Psychological support: Individual therapy, family support, and psychiatric support if necessary are beneficial.
7. Other Medical Follow-ups
Hearing tests: Periodic audiological evaluation for middle and inner ear problems
Vision checks: Follow-up of conditions such as the need for glasses or strabismus
Kidney ultrasound: To evaluate the presence of structural anomaly
Bone density measurement: Should be done especially after puberty for the risk of osteoporosis.
The treatment of Turner syndrome must be carried out with a multidisciplinary approach. Many fields such as endocrinology, cardiology, nephrology, gynecology, psychiatry, genetics, and child development must work together. With early diagnosis and regular follow-up, individuals with Turner syndrome can lead a healthy, productive, and happy life. Although the treatment process is long-term, individuals with a high quality of life can be raised with a conscious and planned approach.