Hermaphroditism

Definition

Hermaphroditism is a rare condition in which ovarian and testicular tissue exist in the same person. The testicular tissue contains seminiferous tubules or spermatozoa. The ovarian tissue contains follicles or corpora albicantia. The condition is the result of a chromosome anomaly.

Description

Among human beings, hermaphroditism is an extremely rare anomaly in which gonads for both sexes are present. External genitalia may show traits of both sexes, and in which the chromosomes show male-female mosaicism (where one individual possesses both the male XY and female XX chromosome pairs). There are two different variants of hermaphroditism: true hermaphroditism and pseudohermaphroditism. There are female and male pseudohermaphrodites. True hermaphroditism refers to the presence of both testicular and ovarian tissue in the same individual. The external genitalia in these individuals may range from normal male to normal female. However, most phenotypic males have hypospadias. Pseudohermaphroditism refers to gonadal dysgenesis.

Genetic profile

The most common karyotype for a true hermaphrodite is 46XX. DNA from the Y chromosome is translocated to one of the X-chromosomes. The karyotype for male pseudohermaphrodites is 46XY. Female pseudohermaphroditism is more complicated. The condition is caused by deficiencies in the activity of enzymes. The genetic basis for three enzyme deficiencies have been identified. Deficiency of 3B hydroxysteroid dehydrogenase—Type 2 is due to an abnormality on chromosome 1p13.1. Deficiency of 21-Hydroxylase is due to an abnormality on chromosome 6p21.3. Deficiency of 11B-Hydroxylase—Type 1 is due to an abnormality on chromosome 8q21.

Demographics

True hermaphrodites are extremely rare. Approximately 500 individuals have been identified in the world to date. Because of the ambiguity of genitalia and difficulties in making an accurate diagnosis, the incidence of pseudohermaphroditism is not well established. The incidence of male pseudohermaphroditism has been estimated at between 3 and 15 per 100,000 people. The incidence of female pseudohermaphroditism has been estimated at between 1 and 8 per 100,000 people.

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Author Info: L. Fleming Fallon Jr., MD, DrPH, The Gale Group Inc., Gale, Detroit, Gale Encyclopedia of Genetic Disorders Part I, 2002

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