Hypogonadism, which affects about one in 5000 people, is an alteration of the gonads (ovaries or testes). This syndrome is often detected around puberty and can be treated with hormonal injections. 

Hypogonadism, also called gonadotropic deficit, is a defect in the reproductive system that causes loss of function of the gonads (ovaries or testes).

The gonads have two functions:

• Produce gametes: eggs or sperm
• Produce hormones: testosterone, estradiol, antimulleric hormone, progesterone, inhibin B

Les types d’hypogonadisme

• Primary hypogonadism: In men, the testes are hypoactive and do not produce enough testosterone.
• Secondary hypogonadism: The pituitary does not secrete hormones that stimulate the testes.

The causes of hypogonadism

• Klinefelter’s syndrome. This syndrome is caused by a chromosomal abnormality where a boy, normally having one X chromosome and one Y chromosome, has at least two X chromosomes and one Y chromosome.
• Cryptorchidism, or undescended testes. One or both of the testicles remain in the abdominal cavity. Usually, the testes descend into the scrotum just before birth. At birth, about 3% of boys have the testicles that have not descended, but in most of them the testes descend spontaneously during the first 4 months of life.
• The absence of Leydig cells. These cells are found in the testes and produce testosterone. Their absence leads to the development of partially developed or ambiguous genitalia. Ambiguous genitalia are not clearly male or female.
• Kallmann’s syndrome. It is a genetic disease causing delayed puberty and impaired sense of smell. Children with this syndrome have a deficiency in sex hormones.
• Prader-Willi syndrome. It is a genetic disease linked to the missing part of a chromosome. The function of the reproductive organs is impaired and delays growth and sexual development.
• Other causes also promote hypogonadism: obesity, trauma to the testicles, use, use of opioids, chemotherapy, etc.

Depending on the causes of the syndrome, hypogonadism can appear in utero, before puberty or in adulthood.

Hypogonadism is a rare disease whose prevalence is poorly understood (around 1/5000).

The symptoms of hypogonadism are all related to primary or secondary sexual characteristics:

• Infant-sized genitals
• Low levels of sex hormones in the blood
• Ambiguous genitalia: they are not clearly male or female 
• Absence of periods or premature menopause
• Delay see absence of puberty
• Low libido and fatigue
• Alteration of secondary sexual characteristics: hairiness, voice, distribution of fat, etc.

Since sex hormone deficiency rarely has consequences in childhood, hypogonadism is often not diagnosed until puberty. 

Diagnosis is based on an exam, blood tests, and sometimes chromosome analysis. Depending on the cause, treatment may include:

• Hormonal treatment: injection of estrogen then estrogen-progestogen in girls, testosterone in boys
• Surgery for cryptorchidism to place undescended testicles back into the scrotum. This intervention generally allows the return of a good functioning of the testicles.
• Treatment against infertility if there is a desire for pregnancy. The pregnancy is then taken care of in a specialized center which may offer gonadotropin injections in certain situations when the ovaries are functional.

The results of rapid management are generally favorable but depend on the severity of the gonadotropic deficit and the age at the start of treatment.

The clinical follow-up and the dosages of the sex hormones allow in men the reduction of fatigue and the resumption of libido and in women, a return of menstruation, less fatigue. 

In the event of hormonal treatment, it is advisable for men to have a regular prostate checkup. Women should be particularly careful with early osteoporosis.