Symptoms and signs
The symptoms of Leydig cell hypoplasia include pseudohermaphroditism, i.e., feminized, ambiguous, or relatively mildly underdeveloped (e.g., micropenis, severe hypospadias, and/or cryptorchidism [undescended testes]) external genitalia, a female gender identity or gender variance, hypergonadotropic hypogonadism (hypogonadism despite high levels of gonadotropins), delayed, impaired, or fully absent puberty with an associated reduction in or complete lack of development of secondary sexual characteristics (sexual infantilism), impaired fertility or complete sterility, tall stature (due to delayed epiphyseal closure), eunuchoid skeletal proportions, delayed or absent bone maturation, and osteoporosis. Cause
Leydig cell hypoplasia is caused by genetic mutations in LHCGR, a gene which encodes the LH/hCG receptor. LH normally acts through the LH/hCG receptor to stimulate the growth of Leydig cells in the testicles and the production of androgens such as testosterone and dihydrotestosterone (DHT) by these cells. In Leydig cell hypoplasia however, there is a reduced capacity for the LH/hCG receptor to respond to LH. This results in hypoplasia or absence of Leydig cells, testicular atrophy, and lower than normal androgen levels. In the most severe form of the condition in which there is a complete lack of response of the Leydig cells to LH, androgen production by the testicles is virtually negligible and secondary sexual characteristics entirely fail to develop at puberty. Diagnosis
Since the Sertoli cells are not affected by Leydig cell hypoplasia, anti-Müllerian hormone is secreted normally and so there are no Müllerian structures. Wolffian structures, such as the prostate, vasa deferentia, and epidydimides are present.
See also
Disorders of sex development
Intersexuality, pseudohermaphroditism, and ambiguous genitalia
Hypogonadism and hypogonadotropic hypogonadism
Familial male-limited precocious puberty (or LH oversensitivity)
Follicle-stimulating hormone insensitivity
Gonadotropin-releasing hormone insensitivity
Inborn errors of steroid metabolism
Isolated 17,20-lyase deficiency
Combined 17α-hydroxylase/17,20-lyase deficiency
17β-Hydroxysteroid dehydrogenase III deficiency
Androgen insensitivity syndrome

References


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