Sexual Differentiation and Development — MCQs

10 questions

A 15-year-old female presents with primary amenorrhea. Her breasts are Tanner stage 4, but she has no axillary or pubic hair. What is the most likely diagnosis?

Which of the following is the least common cause of ambiguous genitalia in a female child

Adrenarche is the maturation of the adrenal cortex leading to increased androgen production. Adrenarche typically starts at the age of:

Delayed puberty in a female is characterized by which of the following?

Which structure may persist as a remnant of the Müllerian duct in males?

If a baby has a XX or XY genotype, normal internal gonads, but ambiguous external genitalia, it is called?

An XX baby presenting with male genitalia (penis and scrotum) is likely due to which of the following conditions?

Congenital adrenal hyperplasia most commonly presents as

A teenage girl presents with a history of amenorrhea. Local examination is shown in the image. What karyotype analysis would you consider for further evaluation?

Q10

13 yr old child visit gynaecology OPD with a complaint of not attaining menarche with karyotype 46XX. On examination, clitoromegaly is seen. Which enzyme is most likely to be deficient in the above condition?

Sexual Differentiation and Development Indian Medical PG Practice Questions and MCQs

Question 1: A 15-year-old female presents with primary amenorrhea. Her breasts are Tanner stage 4, but she has no axillary or pubic hair. What is the most likely diagnosis?

A. Turner's syndrome
B. Complete Androgen Insensitivity Syndrome (CAIS) (Correct Answer)
C. Premature ovarian failure
D. Mullerian agenesis

Explanation: ***Complete Androgen Insensitivity Syndrome (CAIS)*** - Previously known as **Testicular Feminization Syndrome**, this condition presents with **breast development (due to peripheral conversion of androgens to estrogens)** but **absent pubic/axillary hair** due to **androgen receptor insensitivity**. - Affected individuals are **genetically male (46, XY)** but have a female external phenotype and **no uterus**, leading to **primary amenorrhea**. *Turner's syndrome* - Characterized by **gonadal dysgenesis (streak gonads)**, leading to **absent or rudimentary breast development** and **primary amenorrhea**. - Individuals are typically **45, XO** and often present with short stature and characteristic physical features like a webbed neck. *Mullerian agenesis* - Involves the **agenesis or hypoplasia of the Mullerian ducts**, resulting in an **absent or hypoplastic uterus and vagina**. - Patients have **normal breast and pubic/axillary hair development** because their ovaries are functional and produce hormones. *Premature ovarian failure* - Involves the **cessation of ovarian function before age 40**, leading to **menopausal symptoms** and **amenorrhea**. - However, patients would have initially gone through **normal puberty**, including the development of pubic/axillary hair, which is absent in this case.

Question 2: Which of the following is the least common cause of ambiguous genitalia in a female child

A. WNT-4 gene mutation
B. Congenital adrenal hyperplasia
C. Fetal placental aromatase deficiency (Correct Answer)
D. Fetal placental steroid sulfatase deficiency
E. Maternal androgen exposure

Explanation: ***Fetal placental aromatase deficiency*** - This condition is exceedingly rare and is considered one of the **least common genetic causes** of ambiguous genitalia in a female. - Deficiency of **aromatase** in the placenta prevents the conversion of androgens to estrogens, leading to **masculinization of a female fetus**, but this pathway is only a minor contributor to fetal androgenization. *WNT-4 gene mutation* - **WNT-4** is crucial for **female sexual differentiation** and acts as an anti-testis factor. - Mutations can lead to **Müllerian aplasia** and variable degrees of virilization in genetic females, making it a recognized, though not the most common, cause of ambiguous genitalia. *Congenital adrenal hyperplasia* - This is the **most common cause** of ambiguous genitalia in a female, primarily due to **21-hydroxylase deficiency**. - Excess adrenal androgens lead to **virilization** of the external genitalia in genetic females. *Maternal androgen exposure* - Virilization can occur from **maternal sources** such as androgen-secreting tumors, exogenous androgen use, or aromatase inhibitors during pregnancy. - This is an **uncommon but recognized cause**, more frequent than aromatase deficiency but far less common than CAH. *Fetal placental steroid sulfatase deficiency* - This deficiency typically results in **low maternal estrogen levels** and can cause **placental insufficiency** and abnormalities in labor, but it does **not directly cause ambiguous genitalia** in a female fetus. - While it affects steroid metabolism, it does not lead to the accumulation of androgens necessary for virilization of female external genitalia.

Question 3: Adrenarche is the maturation of the adrenal cortex leading to increased androgen production. Adrenarche typically starts at the age of:

A. 7 (Correct Answer)
B. 8
C. 11
D. 12

Explanation: ***7*** - **Adrenarche** typically begins around **6 to 8 years of age**, with some earlier maturation seen in African American children. - This process involves the maturation of the adrenal cortex, leading to increased production of **adrenal androgens** like DHEA and DHEAS. *8* - While 8 years is within the general range, **7 years of age** is often cited as a more precise average onset for adrenarche. - The onset of adrenarche marks the development of **pubic and axillary hair** (pubarche and axillarche) and **body odor**, preceding gonadarche. *11* - An age of 11 years is generally considered the average onset of **gonadarche** (true puberty), which involves the activation of the hypothalamic-pituitary-gonadal axis. - **Adrenarche** precedes gonadarche by several years and is a separate maturational process of the adrenal glands. *12* - By 12 years of age, most children have already undergone **adrenarche** and are well into the stages of gonadarche, experiencing significant pubertal changes. - This age is typically associated with peak pubertal development, including **growth spurts** and more pronounced secondary sexual characteristics.

Question 4: Delayed puberty in a female is characterized by which of the following?

A. Menarche > 16 year (Correct Answer)
B. FSH < 20 in 16 year
C. Menarche occurring more than 1 year after breast budding
D. No breast budding by age 10

Explanation: ***Menarche > 16 year*** - Delayed puberty is defined as the **absence of menarche by 16 years of age**, or the absence of any secondary sexual characteristics by age 13. - This option correctly identifies one of the key diagnostic criteria for delayed puberty in females. *No breast budding by age 10* - This is incorrect; the absence of **breast budding by age 13** is the accepted cutoff for delayed puberty. - Breast development typically begins between ages 8 and 13. *Menarche occurring more than 1 year after breast budding* - This is incorrect; menarche typically occurs within **2 to 3 years** of breast development. A delay of merely one year following breast budding is usually within normal limits. *FSH < 20 in 16 year* - This statement itself does not definitively characterize delayed puberty and requires more context. A **low Follicle-Stimulating Hormone (FSH)** level in a 16-year-old with delayed puberty would suggest a **hypogonadotropic hypogonadism**, whereas high FSH levels would indicate **hypergonadotropic hypogonadism** (e.g., primary ovarian failure). - The threshold of FSH < 20 is not a universal or standalone diagnostic criterion for delayed puberty.

Question 5: Which structure may persist as a remnant of the Müllerian duct in males?

A. Seminal vesicle
B. Epididymis
C. Prostatic utricle (Correct Answer)
D. Ureter

Explanation: ***Prostatic utricle*** - The **Müllerian ducts** (paramesonephric ducts) are primarily female reproductive structures. In males, the **anti-Müllerian hormone (AMH)** causes their regression. - The **prostatic utricle** is a small blind-ended pouch located at the prostatic urethra, representing the remnant of the fused caudal ends of the Müllerian ducts. *Seminal vesicle* - The **seminal vesicles** develop from the **mesonephric (Wolffian) ducts**, not the Müllerian ducts. - They contribute to semen production and are functional male reproductive organs, not remnants of female structures. *Epididymis* - The **epididymis** also develops from the **mesonephric (Wolffian) ducts**. - It functions in sperm maturation and storage and is part of the male reproductive tract, not a Müllerian remnant. *Ureter* - The **ureters** are conduits for urine from the kidneys to the bladder and develop from the **ureteric bud**, an outgrowth of the mesonephric duct, but are distinct from Müllerian structures. - They are part of the urinary system in both sexes and are not considered remnants of the Müllerian duct.

Question 6: If a baby has a XX or XY genotype, normal internal gonads, but ambiguous external genitalia, it is called?

A. True hermaphrodite
B. Disorder of Sex Development (DSD) (Correct Answer)
C. Intersex (outdated term)
D. Any of the above
E. Pseudohermaphrodite

Explanation: ***Disorder of Sex Development (DSD)*** - This is the **current preferred medical terminology** that encompasses conditions where there is a discrepancy between chromosomal sex, gonadal sex, and anatomical sex. - The scenario described—normal XX or XY genotype and normal internal gonads with **ambiguous external genitalia**—fits the definition of a DSD. - This **umbrella term** has replaced older terminology and is the most appropriate answer in modern medical practice. *True hermaphrodite* - A true hermaphrodite, now referred to as **ovotesticular DSD**, possesses both ovarian and testicular tissue simultaneously. - The question specifies **normal internal gonads** (either ovaries or testes, not both), which excludes this diagnosis. *Intersex (outdated term)* - While "intersex" was historically used to describe individuals with atypical sexual characteristics, it is now considered an **outdated and less precise** term in medical contexts. - "Disorder of Sex Development" is the preferred and more comprehensive medical classification. *Pseudohermaphrodite* - This was the **classical medical term** for exactly this presentation: normal chromosomal sex and appropriate internal gonads but ambiguous external genitalia. - Examples include 46,XX DSD with virilization (e.g., **congenital adrenal hyperplasia**) or 46,XY DSD with undervirilization (e.g., **androgen insensitivity syndrome**). - This term has been **replaced by DSD terminology** in modern medical practice to avoid stigmatizing language. *Any of the above* - While multiple terms have been used historically, **DSD is the most accurate and currently accepted medical term** for this specific presentation. - Therefore, this option is incorrect as it suggests all answers are equally valid.

Question 7: An XX baby presenting with male genitalia (penis and scrotum) is likely due to which of the following conditions?

A. Turner syndrome
B. None of the options
C. Klinefelter syndrome
D. High level of testosterone in maternal blood (Correct Answer)

Explanation: ***High level of testosterone in maternal blood*** - An **XX baby** (genetically female) presenting with **fully masculinized external genitalia** (penis and scrotum) indicates significant **androgen exposure** during the critical period of sexual differentiation (8-12 weeks of gestation). - While the most common cause is **congenital adrenal hyperplasia (CAH)** due to fetal androgen excess, **maternal sources of androgens** can also cause complete masculinization. - Maternal causes include **virilizing tumors** (e.g., luteoma of pregnancy, Krukenberg tumor, arrhenoblastoma), **exogenous androgen administration**, or **maternal CAH**. - High sustained maternal testosterone crosses the placenta and causes **virilization of female fetus**, which can range from clitoromegaly to complete male phenotype. - This is the **only medically correct option** among the choices given, though CAH (not listed) would be the most common cause overall. *Klinefelter syndrome* - **47, XXY karyotype** - genetically male due to presence of Y chromosome with SRY gene. - Presents as phenotypic male, not relevant to an **XX individual**. - Features include hypogonadism, infertility, tall stature, and gynecomastia. *Turner syndrome* - **45, X karyotype** - monosomy X, genetically and phenotypically female. - Presents with **female external genitalia**, streak gonads, short stature, webbed neck. - Cannot explain masculinized genitalia in any scenario. *None of the options* - This is incorrect because **high level of testosterone in maternal blood** is a documented cause of XX virilization with male phenotype, though less common than fetal CAH.

Question 8: Congenital adrenal hyperplasia most commonly presents as

A. 46,XY DSD
B. Ovotesticular DSD
C. 46,XX DSD with virilization (Correct Answer)
D. 46,XY DSD with undervirilization

Explanation: ***46,XX DSD with virilization*** (formerly female pseudohermaphroditism) - This is the **most common presentation** of congenital adrenal hyperplasia (CAH), particularly due to **21-hydroxylase deficiency**, which accounts for >90% of CAH cases. - Affects genetically female (46,XX) individuals with excess **androgens** produced by hyperplastic adrenal glands leading to **virilization** of external genitalia. - Clinical features include **clitoromegaly, labioscrotal fusion**, and varying degrees of masculinization, while **internal female organs (uterus, ovaries, fallopian tubes) remain normal**. - This is the classic presentation that brings CAH to clinical attention in newborn screening programs. *46,XY DSD* (formerly 46,XY intersex) - This terminology refers to conditions where genetically male individuals (46,XY) have atypical genital development. - Common causes include **androgen insensitivity syndrome** or disorders of testosterone synthesis (5α-reductase deficiency, 17β-hydroxysteroid dehydrogenase deficiency). - CAH in 46,XY individuals typically presents with **isosexual precocious pseudopuberty** (early virilization) in simple virilizing forms or **salt-wasting adrenal crisis** in severe forms, not undervirilization. *Ovotesticular DSD* (formerly true hermaphroditism) - Very rare condition where an individual has **both ovarian and testicular tissue**, either as separate gonads or combined as ovotestes. - Often involves complex chromosomal patterns including **46,XX/46,XY mosaicism** or 46,XX with SRY translocation. - Not related to CAH pathophysiology, which involves enzymatic defects in steroidogenesis. *46,XY DSD with undervirilization* (formerly male pseudohermaphroditism) - Occurs when 46,XY individuals have **undervirilized or ambiguous external genitalia** due to impaired androgen synthesis or action. - Causes include disorders of testicular development, androgen biosynthesis defects, or **androgen insensitivity**. - While CAH can affect males, it causes **excess androgens** leading to precocious puberty, not undervirilization.

Question 9: A teenage girl presents with a history of amenorrhea. Local examination is shown in the image. What karyotype analysis would you consider for further evaluation?

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

Explanation: ***45 XO*** - The image shows a **webbed neck** and **short stature** (suggested by the overall body proportions typically associated with Ullrich-Turner Syndrome), alongside primary amenorrhea, which are classic features of **Turner Syndrome**. - **Turner Syndrome** is a chromosomal disorder characterized by the absence of all or part of one X chromosome in females, resulting in a **45, XO karyotype**. *46 XY* - This karyotype indicates a **phenotypic male** with normal male chromosomal constitution. - Individuals with this karyotype would not typically present with **primary amenorrhea** as they do not have a uterus. *46 XX* - This is the **normal female karyotype**, and while a female with this karyotype could experience amenorrhea (e.g., due to Asherman's syndrome or PCOS), the physical features associated with the image (like webbed neck) are not consistent. - This option does not explain the **physical stigmata** often seen in genetic causes of primary amenorrhea, such as in Turner syndrome. *47 XXY* - This karyotype is characteristic of **Klinefelter Syndrome**, which affects males and is associated with hypogonadism and gynecomastia. - It would not be found in a female patient presenting with **amenorrhea** and the physical features shown in the image. *47 XXX* - This karyotype represents **Triple X Syndrome** (Trisomy X), which affects females and typically presents with **normal female appearance** and often normal fertility. - While some individuals may have menstrual irregularities, the **distinctive physical features** shown in the image (webbed neck, short stature) are not characteristic of Triple X syndrome, which usually lacks specific dysmorphic features.

Question 10: 13 yr old child visit gynaecology OPD with a complaint of not attaining menarche with karyotype 46XX. On examination, clitoromegaly is seen. Which enzyme is most likely to be deficient in the above condition?

A. 21 alpha-hydroxylase (Correct Answer)
B. 11 beta-hydroxylase
C. 17 alpha-hydroxylase
D. 3 beta-hydroxysteroid dehydrogenase

Explanation: ***21 alpha-hydroxylase*** - A deficiency in **21-alpha-hydroxylase** is the most common cause of **congenital adrenal hyperplasia (CAH)**, leading to **excess androgen production**. [1] - In a 46 XX individual, this excess androgen causes **virilization**, presenting as **clitoromegaly** and **primary amenorrhea** (lack of menarche) due to the suppression of normal ovarian function and early epiphyseal fusion. *11 beta-hydroxylase* - Deficiency of **11-beta-hydroxylase** also leads to **CAH** and androgen excess, causing **virilization**. - However, it is characterized by the accumulation of **11-deoxycorticosterone (DOC)**, which has mineralocorticoid activity, leading to **hypertension**, which is not mentioned in the present case. *17 alpha-hydroxylase* - A deficiency in **17-alpha-hydroxylase** impairs the synthesis of both **androgens** and **estrogens**. - This typically results in **female external genitalia** in 46 XY individuals and **primary amenorrhea** with **lack of secondary sexual characteristics** in 46 XX individuals, often accompanied by **hypertension** due to elevated **DOC**, which contradicts the clitoromegaly seen. *3 beta-hydroxysteroid dehydrogenase* - Deficiency of **3-beta-hydroxysteroid dehydrogenase** impairs the synthesis of all major adrenal steroids (mineralocorticoids, glucocorticoids, and androgens). - In 46 XX individuals, this can cause mild **virilization** due to the accumulation of **DHEA**, but it is also associated with **salt-wasting crises** and **adrenal insufficiency**, which are not indicated here.

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