Intersex syndrome is intermingling of characteristics of both sexes in varying degrees in one individual, including physical form, reproductive organs and sexual behavior. It results from some defect in the embryonic development. It can be divided into four groups:
1. Pure gonadal agenesis: In this condition the testes or ovaries have never developed. The affected individuals have streak gonads [ovaries or testes].
2. Gonadal dysgenesis: In this condition, the external sexual structures are appropriate to the phenotype, but at puberty the testes or the ovaries fail to develop. Two common syndromes that are well known in this category are:
a) Klinefelter’s syndrome: The phenotype is male but the sex chromosome pattern is XXY (47 chromosomes). Features that are seen are gynecomastia, azoospermia, low levels of testosterone, sterility, increased urinary gonadotrophins and increased height. Histology of the gonads shows testicular atrophy with hyalinization of seminiferous tubules.
b) Turner’s syndrome: The phenotype is female and the chromosome pattern is XO. This syndrome is characterized by primary amenorrhoea, sterility, lack of development of primary and secondary sexual characteristics, increased urinary gonadotrophin excretion, pigmented naevi, a short fourth metatarsal, webbed neck and wide set nipples.
3. True hermaphroditism: It is a rare condition of bisexuality characterized by the presence of an ovary and a testicle or two ovotestes in the affected individual. The external genitalia may be of either sex. The uterus may be absent or rudimentary. Phallus may be penile or clitoral. Neither gonad is completely functional.
|| Caption : Sagittal transabdominal ultrasound.
Description : Posterior to the bladder is seen a small structure that could represent a rudimentary uterus.
Please click here to view the source of this image.
4. Pseudo- hermaphroditism: In this condition the gonadal tissue of only one sex is seen internally, but external appearance is of the opposite sex.
a. Male pseudohermaphroditism: [click here to view]
- The genetic sex is XY.
- The gonads are exclusively testes.
- The external genitalia are either ambiguous or completely female.
Male pseudohermaphroditism can occur due to many reasons, common to all of which is defective virilization of the male embryo. Complete androgen
insensitivity syndrome is the most common form, resulting from a mutation in the gene for the androgen receptor. This disorder is inherited as X linked recessive. Its management involves corrective surgery of the genitalia and removal of the testes. Estrogen therapy is begun at the appropriate age to allow development of normal female secondary sex characters.
b. Female pseudohermaphroditism:
- The genetic sex is XX.
- The gonads are ovaries.
- The external genitalia are ambiguous or virilized.
Female pseudohermaphroditism occurs due to excessive and inappropriate exposure to androgenic steroids during the early part of gestation. The commonest condition is congenital adrenal hyperplasia (autosomal recessive trait) that occurs due to classic 21 hydoxylase deficiency. Its manifestations include hypertrophy of clitoris, partial fusion of labioscrotal folds and variable virilization of the urethra. Its management involves surgical correction of the external genitalia and treatment with appropriate glucocorticoids to prevent the consequences of its deficiency and arrest rapid virilization.