Kallman syndrome: symptoms, causes and treatment - psychology - 2023



Kallman's syndrome is a rare disease that causes fertility problems and affects both the production of sex hormones and the sense of smell, causing hypogonadism and anosmia, respectively. This disorder occurs more in men than in women, in a ratio of 5: 1.

In this article we will see what Kallman syndrome consists of, what are its main clinical manifestations and symptoms, how is it diagnosed and what is the indicated treatment.

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What is Kallman syndrome?

Kallman syndrome is a rare inherited disease characterized by the combination of hypogonadotropic hypogonadism and anosmia or hyposmia (absence or decreased sense of smell), due to a deficiency in the secretion of gonadotropin-releasing hormones secondary to a defect in the migration of neurons that release these same substances from the nasal passages to the hypothalamus.

Syndrome It is named after the psychiatrist Franz Kallman, who in 1944 described this disease in detail in three families, postulating its hereditary nature.

People with hypogonadotropic hypogonadism have insufficient or no sexual development. due to a deficiency of sex hormones and low levels of luteinizing and follicle-stimulating hormone (hormones released by the pituitary that regulate sexual reproduction), and also infertility. Anosmia or hyposmia, on the other hand, is related to the absence or hypoplasia (incomplete development) of the olfactory bulb and its tracts.

Kallman's syndrome can be sporadic or familial, and although it can affect both men and women, the latter tend to suffer from it less frequently, around 5 times less than men.

It is a genetically heterogeneous condition and in 60% of cases it is sporadic, with no family history. Research has determined that there are three types of inheritance patterns: X-linked, autosomal dominant, and autosomal recessive.


The clinical symptoms of Kallman syndrome show great variability between patients, even at the intrafamily level.

In men, hypogonadotropic hypogonadism secondary to a deficiency of gonadotropin-releasing hormones may manifest with: micropenis, cryptorchidism (incomplete descent of one or both testicles into the scrotum), absence or incomplete development of secondary sexual characteristics, decreased libido, infertility and erectile dysfunction.

In women, it may appear amenorrhea, absence of breast development, and dyspareunia (painful intercourse),

On the other hand, patients suffering from Kallmann syndrome may present other associated symptoms, which are also due to defects in embryonic genesis and, therefore, are related to the chain of fibroblast growth factors (substances responsible for functions such as blood vessel formation or embryonic development).

The most common alterations associated with this syndrome include the following: synkinesis (involuntary and unconscious jerks that occur when performing voluntary movements), agenesis of the corpus callosum, visuospatial disorder, congenital palpebral ptosis, hearing disturbances, hypodontia (defective development of one or more teeth), unilateral renal agenesis, cleft lip or palate, structural alterations in the feet or hands, obesity and other less frequent disorders.

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The vast majority of cases of Kallman syndrome are diagnosed in adolescence, due to the absence of secondary sexual characteristics, which translates, as regards men, into prepubertal testicles and the absence of virilization; and in women, poor breast development and the presence of primary amenorrhea.

When diagnosing Kallman syndrome, low or normal serum levels of luteinizing hormone and follicle stimulating hormone, with a poor initial response to the administration of gonadotropin-releasing hormone (GnRH), but with a normal response when the hormones are repeatedly injected in pulses.

On the other hand, the pituitary remains in normal conditions, as well as the secretion of pituitary hormones. There is a decrease in steroid sex hormones and serum prolactin levels are at normal levels. Anosmia or hyposmia can be confirmed by medical history or by using specific olfactory tests to identify odors.

Neuroimaging techniquesLike magnetic resonance imaging, they help to make the diagnosis, since they allow to detect the absence or hypoplasia of the olfactory bulbs; however, in up to 25% of patients this brain structure may be in perfect condition, and in those cases genetic studies must be carried out that can provide more clues for an accurate diagnosis.

In order to diagnose Kallman syndrome, there are also molecular techniques such as: fluorescent in situ hybridization, a chromosome marking technique by means of which these are hybridized with probes that emit fluorescence and allow the visualization, distinction and study of chromosomes and their anomalies; and comparative genomic hybridization, another cytogenetic technique that makes it possible to analyze the quantity and structure of chromosomes by comparing them with a reference one.


Treatment of patients with Kallman syndrome has two goals: improve fertility and treat hypogonadism. For the latter, it is necessary to stimulate the development of secondary sexual characteristics. This is achieved through hormone replacement therapy with testosterone, in the case of men; and with combined estrogens and progesterone, if women are affected.

Testosterone therapy is a safe treatment today And it can be done by intramuscular injections, or by using topical gels and liquids.

Hormone replacement treatment in women It usually consists of taking pills and oral drugs, with a medical follow-up that guarantees a correct therapeutic process.

With regard to fertility treatment, human menopausal gonadotropin or recombinant follicle-stimulating hormone (FSH) can be used to stimulate sperm production; and to stimulate folliculogenesis, the maturation process of the ovarian follicle, recombinant FSH or gonadotropin-releasing hormone can be administered in pulses.

In relation to anosmia or hyposmia, also characteristic of Kallman syndrome, there is still no specific treatment available. Patients are often advised to reduce associated risks, such as: avoiding foods that may have expired, if no one else can confirm whether a food is fresh; or not cooking or heating with natural gas at home, as they may have a hard time detecting possible leaks.

Finally, it should be noted that it is possible that the person suffering from this disease may suffer other types of alterations, such as the deterioration of the health of the bones, for example. It is important to perform a bone mineral density test to measure the amount of calcium and other minerals and to prevent the development of osteoporosis.