Turner syndrome — MCQs

10 questions

A 14-year-old girl is brought to the physician because she frequently experiences cramping and pain in her legs during school sports. She is at the 10th percentile for height. Her blood pressure is 155/90 mm Hg. Examination shows a high-arched palate with maloccluded teeth and a low posterior hairline. The patient has a broad chest with widely spaced nipples. Pelvic examination shows normal external female genitalia with scant pubic hair. Without appropriate treatment, this patient is at the greatest risk of developing which of the following complications?

A 16-year-old girl is brought to the physician because she has not yet had her 1st period. She was born at 39 weeks gestation via spontaneous vaginal delivery. She is up to date on all vaccines and meeting all developmental milestones. She has no history of a serious illness and takes no medications. Physical examination shows underdeveloped breasts with scant pubic and axillary hair. Speculum examination shows a short vagina and no cervix. The remainder of the physical examination shows no abnormalities. Pelvic ultrasound shows no uterus. Which of the following is the most likely karyotype in this patient?

A 16-year-old girl presents with primary amenorrhea. On exam, you note that she is short and has a shield chest. You order abdominal imaging, which suggests the presence of streak gonads. Of the choices listed below, which of the following karyotypes is possible in this patient? I: 45,XO II: 45,XO/46,XX mosaicism III: 46,X,del(Xp) or other structural X abnormalities

A 19-year-old woman presents to her gynecologist’s office stating that she has never had a period. She is slightly alarmed because most of her friends in college have been menstruating for years. She is also concerned about her short stature. When she previously visited her family physician during early puberty, she was told that she will gain the appropriate height during her final teenage years. However, over the past few years, she has gained only a couple of inches. On examination, she has a wide chest and short neck. Her breast development is at Tanner stage 1. Her external genitalia is normal with sparse hair distribution over the mons pubis. Her gynecologist suspects a genetic condition and sends her for genetic counseling. Based on her clinical findings, which of the following diseases is she most likely to develop?

A 19-year-old male from rural West Virginia presents to his family medicine doctor to discuss why he is having trouble getting his wife pregnant. On exam, he is 6 feet 2 inches with a frail frame and broad hips for a male his size. He is noted to have mild gynecomastia, no facial hair, and small, underdeveloped testes. He claims that although he has a lower libido than most of his friends, he does have unprotected sex with his wife. His past medical history is notable for developmental delay and difficulties in school. What is the most likely chromosomal abnormality in this patient?

A 14-year-old girl comes to the physician for exertional leg pain. The pain began last week when she started jogging to lose weight. She is at the 5th percentile for height and 80th percentile for weight. Physical examination shows a broad neck with bilateral excess skin folds that extend to the shoulders, as well as a low-set hairline and ears. There is an increased carrying angle when she fully extends her arms at her sides. Pulses are palpable in all extremities; lower leg pulses are delayed. Which of the following additional findings is most likely in this patient?

A 14-year-old boy is brought to the physician by his parents for a well-child visit. The patient was born at 38 weeks' gestation via vaginal delivery and has been healthy. He attends a junior high school and is having difficulties keeping up with his classmates in many classes. He is at the 97th percentile for height and 50th percentile for weight. Vital signs are within normal limits. Cardiac examination shows a high-frequency midsystolic click that is best heard at the left fifth intercostal space. The patient has long extremities along with excess breast tissue bilaterally. He has no axillary hair. Genital examination shows reduced scrotal size and a normal sized penis. Which of the following tests is the most likely to diagnose the patient's underlying disorder?

A 17-year-old girl is being evaluated for primary amenorrhea. A pelvic ultrasound shows no uterus, fallopian tubes, or ovaries, despite having normal external sexual organs. On physical examination, there is no axillary or pubic hair, and breast development is normal. The laboratory tests show evidence of increased serum testosterone with normal conversion to dihydrotestosterone (DHT) and increased luteinizing hormone (LH). What is the karyotype of this patient?

The medical student on the pediatric cardiology team is examining a 9-year-old girl who was referred by her primary care physician for unexplained hypertension. She is accompanied by her mother who reveals that the child is generally well but has been significantly less active than her peers for the past year. On exam, the medical student notes a thin girl in no apparent distress appearing slightly younger than stated age. Vital signs reveal a BP is 160/80, HR 80, RR 16. Physical exam is notable only for a clicking sound is noted around the time of systole but otherwise the cardiac exam is normal. Pedal pulses could not be palpated. Which of the following physical exam findings was most likely missed by both the medical student and primary care physician?

Q10

A 5-year-old girl presents to the physician with increased muscle cramping in her lower extremities after walking extended distances. The young girl is in the 10th percentile for height. Her past medical history is notable only for a cystic hygroma detected shortly after birth. Which of the following findings is most likely in this patient?

Turner syndrome US Medical PG Practice Questions and MCQs

Question 1: A 14-year-old girl is brought to the physician because she frequently experiences cramping and pain in her legs during school sports. She is at the 10th percentile for height. Her blood pressure is 155/90 mm Hg. Examination shows a high-arched palate with maloccluded teeth and a low posterior hairline. The patient has a broad chest with widely spaced nipples. Pelvic examination shows normal external female genitalia with scant pubic hair. Without appropriate treatment, this patient is at the greatest risk of developing which of the following complications?

A. Alzheimer disease
B. Hyperphagia
C. Pulmonary stenosis
D. Osteoporosis (Correct Answer)
E. Severe acne

Explanation: ***Osteoporosis*** - This patient's presentation with **short stature**, high blood pressure, **webbed neck** (implied by low posterior hairline), and **wide-spaced nipples** is highly suggestive of **Turner syndrome (45,X0)**. - Turner syndrome is characterized by **gonadal dysgenesis**, leading to **estrogen deficiency**, which is a major risk factor for developing **osteoporosis**. - Without estrogen replacement therapy, patients with Turner syndrome have significantly increased risk of **low bone mineral density** and **fractures**. *Pulmonary stenosis* - While Turner syndrome is associated with **cardiac anomalies** such as **bicuspid aortic valve** and **coarctation of the aorta**, these are typically **congenital defects** present from birth rather than complications that develop over time. - **Pulmonary stenosis** itself is not a primary cardiac finding in Turner syndrome. - The question asks about complications that develop without treatment, making **osteoporosis** more appropriate as it progressively worsens due to chronic **estrogen deficiency**. *Alzheimer disease* - **Alzheimer disease** is a neurodegenerative disorder primarily associated with aging and genetics, not typically a direct complication of Turner syndrome. - While cognitive profiles in Turner syndrome can differ (particularly with visuospatial skills), there is no established increased risk of Alzheimer disease. *Hyperphagia* - **Hyperphagia** (excessive eating) is characteristically associated with **Prader-Willi syndrome** due to hypothalamic dysfunction. - It is not a feature or complication of **Turner syndrome**. *Severe acne* - **Severe acne** is often related to increased androgen levels or hormonal fluctuations during puberty. - In Turner syndrome, there is typically **hypogonadism** and **estrogen deficiency**, which would not predispose to severe acne.

Question 2: A 16-year-old girl is brought to the physician because she has not yet had her 1st period. She was born at 39 weeks gestation via spontaneous vaginal delivery. She is up to date on all vaccines and meeting all developmental milestones. She has no history of a serious illness and takes no medications. Physical examination shows underdeveloped breasts with scant pubic and axillary hair. Speculum examination shows a short vagina and no cervix. The remainder of the physical examination shows no abnormalities. Pelvic ultrasound shows no uterus. Which of the following is the most likely karyotype in this patient?

A. 47,XXY
B. 45,X
C. 46,XY (Correct Answer)
D. 46,XX/46,XY
E. 46,XX

Explanation: ***46,XY*** - This karyotype describes an individual who is genetically male but presents phenotypically as female, often seen in **androgen insensitivity syndrome (AIS)**. - The patient's underdeveloped breasts, scant pubic/axillary hair, short vagina with no cervix, and absent uterus (on ultrasound) are classic signs of AIS, where **testosterone is produced but tissues are unresponsive** due to receptor defects, leading to female external genitalia development and lack of Müllerian structures. *47,XXY* - This karyotype is associated with **Klinefelter syndrome**, which affects males and typically presents with tall stature, small testes, gynecomastia, and infertility. - It does not explain the absence of a uterus or Mullerian structures, nor the specific presentation of underdeveloped secondary sexual characteristics in a phenotypic female. *45,X* - This karyotype describes **Turner syndrome**, which presents with primary amenorrhea, short stature, webbed neck, and **streak gonads** (absent or non-functional ovaries). - While it causes primary amenorrhea and underdeveloped secondary sexual characteristics, Turner syndrome patients typically have a **uterus** (though small) and do not have an absent cervix or a short vagina in the way described. *46,XX/46,XY* - This represents **gonadal mosaicism**, where an individual has cell lines with both male and female karyotypes. - The clinical presentation can be highly variable, ranging from ambiguous genitalia to female or male phenotypes, but it does not specifically account for the precise combination of primary amenorrhea, absent uterus, and underdeveloped secondary sexual characteristics as seen in AIS. *46,XX* - This is the normal female karyotype. While it can be associated with primary amenorrhea in conditions such as **Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome** (agenesis of the uterus and upper vagina), it would be accompanied by normal breast and pubic/axillary hair development due to functional ovaries. - The patient's underdeveloped breasts and scant pubic/axillary hair suggest a problem with androgen action, not simply Müllerian agenesis in an otherwise hormonally normal female.

Question 3: A 16-year-old girl presents with primary amenorrhea. On exam, you note that she is short and has a shield chest. You order abdominal imaging, which suggests the presence of streak gonads. Of the choices listed below, which of the following karyotypes is possible in this patient? I: 45,XO II: 45,XO/46,XX mosaicism III: 46,X,del(Xp) or other structural X abnormalities

A. I and III
B. I, II, and III (Correct Answer)
C. II and III
D. I and II
E. I only

Explanation: ***I, II, and III*** - The patient's presentation with **primary amenorrhea**, **short stature**, a **shield chest**, and **streak gonads** is classic for **Turner syndrome**. - All three listed karyotypes (I: **45,XO**, II: **45,XO/46,XX mosaicism**, and III: **46,X,del(Xp)** or other structural X abnormalities) are recognized variants that cause Turner syndrome. *I and III* - This option incorrectly excludes 45,XO/46,XX mosaicism, which is a common and clinically significant **karyotype in Turner syndrome**. - Mosaicism can lead to a milder phenotype but still presents with the characteristic features described. *II and III* - This option incorrectly excludes **45,XO**, which is the most classic and common karyotype found in individuals with Turner syndrome. - The absence of a second X chromosome is the hallmark genetic defect. *I and II* - This option incorrectly excludes **structural X abnormalities** (e.g., deletion of the short arm of the X chromosome, **46,X,del(Xp)**), which are known causes of Turner syndrome. - These structural changes lead to a similar clinical picture due to the loss of critical genes on the X chromosome. *I only* - While **45,XO** is the most common karyotype in Turner syndrome, confining the possibility to only this option is too restrictive. - Both mosaicism and structural X abnormalities also result in the clinical features of Turner syndrome.

Question 4: A 19-year-old woman presents to her gynecologist’s office stating that she has never had a period. She is slightly alarmed because most of her friends in college have been menstruating for years. She is also concerned about her short stature. When she previously visited her family physician during early puberty, she was told that she will gain the appropriate height during her final teenage years. However, over the past few years, she has gained only a couple of inches. On examination, she has a wide chest and short neck. Her breast development is at Tanner stage 1. Her external genitalia is normal with sparse hair distribution over the mons pubis. Her gynecologist suspects a genetic condition and sends her for genetic counseling. Based on her clinical findings, which of the following diseases is she most likely to develop?

A. Cystic medial necrosis
B. Coarctation of aorta (Correct Answer)
C. Supravalvular aortic stenosis
D. Intellectual disability
E. Endocardial cushion defects

Explanation: ***Coarctation of aorta*** - The patient's presentation with **primary amenorrhea**, **short stature**, a **wide chest**, and **short neck** are classic signs of **Turner syndrome (45, XO)**. - **Coarctation of the aorta** is a common cardiovascular anomaly associated with Turner syndrome, occurring in approximately 10-20% of affected individuals. *Cystic medial necrosis* - This condition is associated with conditions like **Marfan syndrome** or **Ehlers-Danlos syndrome**, which present with different physical features, such as tall stature and joint hypermobility. - While it can lead to aortic dissection, it is not a characteristic cardiovascular anomaly of Turner syndrome. *Supravalvular aortic stenosis* - This is a feature more commonly associated with **Williams syndrome**, which involves distinct facial features, intellectual disability, and a cheerful personality, none of which are described in this patient. - It involves narrowing of the ascending aorta above the aortic valve, but is not typically linked to Turner syndrome. *Intelligence disability* - Patients with **Turner syndrome typically have normal intelligence**, although they may experience specific learning difficulties, particularly in visuospatial tasks. - Significant intellectual disability is not a characteristic feature of this syndrome. *Endocardial cushion defects* - These defects, particularly **atrioventricular septal defects**, are classically associated with **Down syndrome (Trisomy 21)**. - They are not a common cardiovascular defect seen in Turner syndrome.

Question 5: A 19-year-old male from rural West Virginia presents to his family medicine doctor to discuss why he is having trouble getting his wife pregnant. On exam, he is 6 feet 2 inches with a frail frame and broad hips for a male his size. He is noted to have mild gynecomastia, no facial hair, and small, underdeveloped testes. He claims that although he has a lower libido than most of his friends, he does have unprotected sex with his wife. His past medical history is notable for developmental delay and difficulties in school. What is the most likely chromosomal abnormality in this patient?

A. Trisomy 13
B. 45: XO
C. Trisomy 21
D. 47: XYY
E. 47: XXY (Correct Answer)

Explanation: ***47: XXY*** - The patient's presentation with **infertility**, small testes, **gynecomastia**, eunuchoid body habitus (tall, frail frame, broad hips), lack of facial hair, and **developmental delay** are classic features of **Klinefelter syndrome (47, XXY)**. - This chromosomal abnormality leads to primary **hypogonadism** due to the presence of an extra X chromosome in males. *Trisomy 13* - Trisomy 13, or **Patau syndrome**, is characterized by severe developmental anomalies, including **cleft lip and palate**, polydactyly, and severe neurological defects. - Infants with Trisomy 13 rarely survive beyond the first year and do not present with the described signs of hypogonadism or gynecomastia in adolescence. *45: XO* - **45, XO** or **Turner syndrome** affects females and is characterized by **short stature**, primary amenorrhea, webbed neck, and **gonadal dysgenesis (streak gonads)**. - This karyotype is incompatible with a male phenotype and the symptoms described. *Trisomy 21* - Trisomy 21, or **Down syndrome**, is associated with distinct facial features, intellectual disability, and congenital heart defects. - While individuals with Down syndrome may have fertility issues, they do not typically present with the specific combination of **gynecomastia**, eunuchoid habitus, and **small testes** seen in this patient. *47: XYY* - **47, XYY syndrome** is associated with increased height and potentially some learning difficulties, but typically does not cause the significant **hypogonadism**, **gynecomastia**, or **small testes** seen in this patient. - Men with 47, XYY usually have normal sexual development and fertility, though some may experience learning disabilities or behavioral problems.

Question 6: A 14-year-old girl comes to the physician for exertional leg pain. The pain began last week when she started jogging to lose weight. She is at the 5th percentile for height and 80th percentile for weight. Physical examination shows a broad neck with bilateral excess skin folds that extend to the shoulders, as well as a low-set hairline and ears. There is an increased carrying angle when she fully extends her arms at her sides. Pulses are palpable in all extremities; lower leg pulses are delayed. Which of the following additional findings is most likely in this patient?

A. Triphalangeal thumb
B. Absent uterus
C. Horseshoe adrenal gland
D. Ovarian dysgenesis (Correct Answer)
E. Mitral valve prolapse

Explanation: ***Ovarian dysgenesis*** - The patient's presentation with **short stature** (5th percentile for height), **webbed neck**, low-set hairline and ears, and increased carrying angle are classic features of **Turner syndrome (45,XO)**. - **Ovarian dysgenesis (streak gonads)** is a hallmark of Turner syndrome, leading to **primary amenorrhea** and **infertility**, which would be a likely additional finding as she approaches puberty. *Triphalangeal thumb* - A triphalangeal thumb is a feature associated with conditions like **Fanconi anemia** or **Holt-Oram syndrome**, which have different constellations of anomalies (e.g., bone marrow failure, cardiac defects). - These syndromes do not typically present with the specific phenotypic features of **webbed neck** or **increased carrying angle** seen in this patient. *Absent uterus* - An absent uterus, or **Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome**, presents with normal ovaries and female secondary sexual characteristics despite the lack of a uterus. - This condition does not explain the patient's **short stature**, **webbed neck**, or **cardiovascular findings** (delayed lower leg pulses suggestive of coarctation of the aorta), which are classic for Turner syndrome. *Horseshoe adrenal gland* - A **horseshoe adrenal gland** is a rare congenital anomaly, often noted incidentally, and is not specifically associated with Turner syndrome or the patient's observed phenotypic features. - While kidney anomalies (e.g., horseshoe kidney) are common in Turner syndrome, adrenal abnormalities generally are not a prominent feature. *Mitral valve prolapse* - Although **cardiac defects** are common in Turner syndrome, the most frequent are **bicuspid aortic valve** and **coarctation of the aorta**, suggested by the delayed lower leg pulses. - While mitral valve prolapse can occur in the general population, it is not as specifically or commonly associated with Turner syndrome as **aortic anomalies**.

Question 7: A 14-year-old boy is brought to the physician by his parents for a well-child visit. The patient was born at 38 weeks' gestation via vaginal delivery and has been healthy. He attends a junior high school and is having difficulties keeping up with his classmates in many classes. He is at the 97th percentile for height and 50th percentile for weight. Vital signs are within normal limits. Cardiac examination shows a high-frequency midsystolic click that is best heard at the left fifth intercostal space. The patient has long extremities along with excess breast tissue bilaterally. He has no axillary hair. Genital examination shows reduced scrotal size and a normal sized penis. Which of the following tests is the most likely to diagnose the patient's underlying disorder?

A. Urinalysis
B. Southern blot
C. Slit-lamp examination
D. Karyotyping (Correct Answer)
E. Serum IGF-1 measurement

Explanation: ***Karyotyping*** - The patient's presentation with **tall stature**, **long extremities**, **gynecomastia**, **small testes**, and **learning difficulties** is highly suggestive of **Klinefelter syndrome (47,XXY)**. - **Karyotyping** is the definitive diagnostic test for Klinefelter syndrome as it identifies the presence of an extra X chromosome. *Urinalysis* - This test is used to detect various kidney and urinary tract conditions and would not identify a **chromosomal abnormality**. - While it can reveal issues like **proteinuria** or **hematuria**, these are not consistent with the primary presenting symptoms. *Southern blot* - This technique detects specific **DNA sequences** and is used for conditions like **fragile X syndrome** or **gene deletions**, but it is not the primary diagnostic tool for **aneuploidies** like Klinefelter syndrome. - Karyotyping provides a broader overview of the entire **chromosome set**, which is necessary to identify an extra chromosome. *Slit-lamp examination* - This examination is used to visualize the eyes and is relevant for conditions like **Marfan syndrome** (**ectopia lentis**) or other ocular abnormalities, which are not the primary concern here. - There are no symptoms presented that would suggest the need for a **slit-lamp examination**. *Serum IGF-1 measurement* - **Insulin-like growth factor 1 (IGF-1)** is measured to assess **growth hormone levels** and diagnose conditions like **acromegaly** or **dwarfism**. - While the patient is tall, his other features (gynecomastia, small testes, learning difficulties) point strongly to a **chromosomal disorder** rather than a primary growth hormone abnormality.

Question 8: A 17-year-old girl is being evaluated for primary amenorrhea. A pelvic ultrasound shows no uterus, fallopian tubes, or ovaries, despite having normal external sexual organs. On physical examination, there is no axillary or pubic hair, and breast development is normal. The laboratory tests show evidence of increased serum testosterone with normal conversion to dihydrotestosterone (DHT) and increased luteinizing hormone (LH). What is the karyotype of this patient?

A. 47, XXY
B. 45, X0
C. 46, XX
D. 46, XY (Correct Answer)
E. 47, XXX

Explanation: ***46, XY*** - This patient presents with **complete androgen insensitivity syndrome (CAIS)**. Despite having a **46, XY karyotype** (genetically male), the body's cells are unable to respond to androgens. - While genetically male, the lack of androgen action prevents the development of male internal and external genitalia, leading to the development of **female external genitalia** and **normal breast development** due to estrogen action (from androgen aromatization) but no uterus, fallopian tubes, or ovaries. The **absence of axillary and pubic hair** (secondary sex characteristics dependent on androgens) further supports CAIS, along with high testosterone and LH. *47, XXY* - This karyotype corresponds to **Klinefelter syndrome**, a condition in which individuals are genetically male with an extra X chromosome. - Individuals with Klinefelter syndrome typically present with **hypogonadism**, **gynecomastia**, and are phenotypically male, often with small testes and infertility. They would not present with female external genitalia or absent internal female organs as described. *45, X0* - This karyotype describes **Turner syndrome**, characterized by the absence of one X chromosome, typically resulting in a female phenotype. - Patients with Turner syndrome usually present with **primary amenorrhea**, **streak gonads**, **short stature**, and **lack of breast development** (due to ovarian failure), which contradicts the normal breast development seen in this patient. *46, XX* - This is the normal female karyotype. A patient with this karyotype would typically have **normal female internal and external genitalia**, including a uterus, fallopian tubes, and ovaries. - The absence of a uterus, fallopian tubes, and ovaries in this patient, along with normal breast development but absent axillary/pubic hair, rules out a normal female karyotype. *47, XXX* - This karyotype refers to **Triple X syndrome**, which typically results in a female phenotype. - Women with Triple X syndrome are often phenotypically normal and fertile, although some may experience **learning difficulties** or **mild developmental delays**. They would generally have **normal female internal and external reproductive organs**, which is contrary to the findings in this case.

Question 9: The medical student on the pediatric cardiology team is examining a 9-year-old girl who was referred by her primary care physician for unexplained hypertension. She is accompanied by her mother who reveals that the child is generally well but has been significantly less active than her peers for the past year. On exam, the medical student notes a thin girl in no apparent distress appearing slightly younger than stated age. Vital signs reveal a BP is 160/80, HR 80, RR 16. Physical exam is notable only for a clicking sound is noted around the time of systole but otherwise the cardiac exam is normal. Pedal pulses could not be palpated. Which of the following physical exam findings was most likely missed by both the medical student and primary care physician?

A. Long philtrum
B. Prominent occiput
C. Webbed neck (Correct Answer)
D. Cleft palate
E. Single palmar crease

Explanation: ***Webbed neck*** - The combination of **hypertension** with **unpalpable pedal pulses** and a **systolic click** in a pediatric patient strongly suggests **coarctation of the aorta**. - **Webbed neck** (or **pterygium colli**) is a classic phenotypic feature associated with **Turner syndrome**, which frequently co-occurs with coarctation of the aorta. *Long philtrum* - A **long philtrum** is a craniofacial feature sometimes associated with certain genetic syndromes like **fetal alcohol syndrome** or **Marfan syndrome**, but it is not specifically linked to coarctation of the aorta or Turner syndrome. - While these syndromes can have cardiovascular manifestations, a long philtrum does not directly point to the specific findings presented. *Prominent occiput* - A **prominent occiput** is a non-specific finding that can be seen in various conditions, including some **chromosomal abnormalities** or **skeletal dysplasias**. - It is not a characteristic feature of **Turner syndrome** or **coarctation of the aorta**. *Cleft palate* - **Cleft palate** is a birth defect affecting the roof of the mouth, often associated with a wide range of genetic or environmental factors. - While patients with cleft palate can have associated congenital heart defects, it is not a direct or common association with **Turner syndrome** or **coarctation of the aorta**. *Single palmar crease* - A **single palmar crease** (simian crease) is a dermatoglyphic feature often associated with **Down syndrome** (Trisomy 21). - While Down syndrome is associated with various congenital heart defects (e.g., AV septal defect), it is not typically associated with **coarctation of the aorta** or **Turner syndrome**.

Question 10: A 5-year-old girl presents to the physician with increased muscle cramping in her lower extremities after walking extended distances. The young girl is in the 10th percentile for height. Her past medical history is notable only for a cystic hygroma detected shortly after birth. Which of the following findings is most likely in this patient?

A. Inferior erosion of the ribs
B. Barr bodies on buccal smear
C. Apparent hypertrophy of the calves
D. Endocardial cushion defect
E. Differential blood pressures between upper and lower extremities (Correct Answer)

Explanation: ***Differential blood pressures between upper and lower extremities*** - This patient's presentation of **muscle cramping** in the lower extremities after exertion (claudication), being in the **10th percentile for height**, and history of **cystic hygroma** is highly suggestive of **Turner syndrome** (45,XO). - A common cardiovascular anomaly associated with Turner syndrome is **coarctation of the aorta**, which causes **higher blood pressure in the upper extremities** compared to the lower extremities due to narrowing of the aorta, typically distal to the left subclavian artery. - This finding is the **classic clinical sign** on physical examination and would be present at any age when coarctation exists, making it the most likely finding in this **5-year-old patient**. - The reduced blood flow to the lower extremities explains the muscle cramping with exertion (intermittent claudication). *Inferior erosion of the ribs* - **Rib notching** (inferior erosion) is indeed associated with **coarctation of the aorta** due to collateral circulation through dilated intercostal arteries. - However, this is a **chronic radiological finding** that typically develops over many years and is more commonly seen in **older children and adults** with long-standing coarctation. - In a **5-year-old child**, rib notching is **unlikely to have developed yet**, making differential blood pressures a more likely finding at this age. *Apparent hypertrophy of the calves* - **Calf pseudohypertrophy** is characteristic of **Duchenne muscular dystrophy**, a progressive X-linked recessive disorder typically affecting boys by age 3-5, caused by dystrophin deficiency leading to fatty and fibrous tissue replacement of muscle. - While both conditions can present in childhood, this patient's **female sex**, history of **cystic hygroma**, and **short stature** point toward Turner syndrome rather than Duchenne muscular dystrophy. *Endocardial cushion defect* - **Endocardial cushion defects** (including atrioventricular septal defects) are classically associated with **Down syndrome** (Trisomy 21). - While congenital heart defects are common in Turner syndrome (occurring in 30-50% of patients), **bicuspid aortic valve** and **coarctation of the aorta** are the most characteristic cardiac anomalies, not endocardial cushion defects. *Barr bodies on buccal smear* - **Barr bodies** represent an **inactivated X chromosome** and are visible in cells with at least two X chromosomes (e.g., normal XX females). - **Turner syndrome** is characterized by **monosomy X** (45,XO), meaning there is only one X chromosome and thus **no Barr bodies** would be found on buccal smear.

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free