What is the most common cause of primary hypogonadism (hypergonadotrophic hypogonadism)? [AI 10]
Klinefelter syndrome
What are the important features of Klinefelter's syndrome? [IOM 06]
Klinefelter's syndrome is characterized by small, firm testes, testicular atrophy, [IOM 04], azoospermia, [UP 01] gynecomastia, and elevated levels of plasma gonadotropins in men with 2 or more X chromosomes.
The common karyotype is 47XXY. [MP 01, MANIPAL 01]
Presence of inactivated X chromosome (Barr body).
Most common causes of primary hypogonadism in males.
Presents with testicular atrophy; a eunuchoid body shape; tall, long extremities; gynecomastia; and female hair distribution.
Mild mental deficiency present. [AIIMS 91]
Abnormality of thyroid function, diabetes mellitus, and pulmonary disease may be present.
The risk of breast cancer is 20 times than that of normal men.
Which of the following is true regarding Klinefelter syndrome? [AI 96, 98]
C) Subnormal intelligence
What are the features of Kallmann syndrome?
Decreased GnRH leading to secondary hypogonadism (hypogonadotrophic hypogonadism) [AI 10]
X-linked : single gene defect
Anosmia [PGI 01] (d/t hypoplasia of olfactory bulb) - permanent even after treatment.
Gynecomastia
Low FSH, LH
Low testosterone
Treatment is with testosterone or synthetic GnRH
A child with decreased levels of LH, FSH and testosterone presents with delayed puberty. Which of the following is the most likely diagnosis: [AI 12]
B. Kallman's syndrome
In Klinefelter and Testicular infection (viral orchitis); there is hypergonadotrophic hypogonadism.
Androgen insensitivity syndrome is hypogonadism d/t end organ resistance to action of testosterone (so normal or elevated testosterone).
Causes of hyperogonadotrophic hypogonadism in males (Primary testicular failure)
- Klinefelter's syndrome
- Noonan syndrome (Nelson's)
- Cryptorchidism
- Testicular infections (infectious orchitis)
- Testicular trauma/torsion
- Cancer chemotherapy and radiation
- Anorchia syndrome (testicular agenesis)
- Myotonic dystrophy (testicular atrophy)
What are the features of turner's syndrome? [AIIMS 98,00, UP 00,AI 04,11]
Gonadal dysgenesis or Turners syndrome is characterized by primary amenorrhea, sexual infantilism, short stature, multiple congenital abnormalities and bilateral streak gonads in phenotypic woman with several defects of the X-chromosome. 50% of cases has 45,XO karyotype. [MANIPAL 02, AI 03]
Hypergonadotrophic hypogonadism.
Lymphedema of the hands and feet, webbing of neck, low posterior hairline, redundant skin folds on the back of neck, a shieldlike chest with widely placed nipples are other features.
Increased carrrying angle, short fourth metacarpal.
There is no breast development [UP 99] unless exogenous estrogen in given.
10-20% have coarctation of aorta. [AI 95]
Renal malformations (horse shoe kidney), pigmented nevi, hypoplastic nails, glucose intolerane are other features.
On USG, finding of cystic hygroma is suggestive of:
B. Turner's syndrome
- cystic hygroma of neck is suggestive but not specific for Turner's syndrome
Why is there cystic hygroma in Turner's syndrome?
Cystic hygroma is is common in Turner's syndrome due to defective draining lymphatics.
It is the reason for edema of the limbs.[AIIMS 2003]
The loose skin in the neck (web neck) is due to shrinkage of cystic hygroma.
What is pure gonadal dysgenesis?
Some phenotypically and genetically normal females have gonadal lesions identical to 45.X patients but without somatic features of Turner syndrome, this condition is termed as pure gonadal dysgenesis or pure ovarian dysgenesis.
This disorder is rarely recognized in children because the external genitals are normal, no other abnormalities are visible, and the growth is normal.
At pubertal age, sexual maturation fails to take place.
Plasma gonadotropin level are elevated.
Delay in epiphyseal fusion results in a eunuchoid habitus.
Tumor of gonads have been reported in these patients.
Treatment consists of estrogen replacement therapy.
What are the features of Noonan's syndrome? [AI 97,03]
Noonan's syndrome is also called as XY Turner phenotype.
It is an autosomal dominant disorder seen in both sexes.
It is characterized by webbed neck, short stature, congenital heart disease, cubitus valgus and other congenital defects despite normal karyotypes and normal gonads.
Antimongoloid slant - condition in which the nasal corners of the palpebral fissure are higher than the temporal corners, as opposed to the typical mongoloid slant.
The cardiac defect is most often the pulmonary valvular stenosis [AIIMS 95], hypertrophic cardiomyopathy or atrial septal defect, whereas coarctation of aorta is rare; the reverse is true for 'true' Turner syndrome.
Males frequently have cryptoorchidism and small testes, puberty is delayed 2 years on average.
Girls have normal sexual maturation, but is delayed 2 years on average and premature ovarian failure has been reported.
Noonan's syndrome has mental retardation, but Turners syndrome patients do not have mental retardation.
[@ NOONans is 12q and autosomal dominant, in noonans NOON sounds like afterNOON , so noon is 12 and at that time it will be sunny so sun is dominant at that time]
What are the causes of male and female pseudohermophroditism ?
Male - testicular feminization, complete androgen insensitivity syndrome
Female - CAH, androgens producing tumors
Which of the following is the most common cause of female pseudohermaphroditism [AIIMS 02]
D) CAH
Congenital adrenal hyperplasia due to classic 21-hydroxylase deficiency [AI 92] is the most common cause of ambigious genitalia in the newborn.
Y chromosome is always present is which of the following conditions [SGPGI 99]
B) Klinefelter syndrome
What are the important causes of gynecomastia? [AI 94,98,UP 96]
