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Kallmann syndrome – frequently asked questions. Part 1.

June 7, 2011

Kallmann Syndrome + Hypogonadotrophic Hypogonadism

Frequently Asked questions

These questions and  answers are meant as a brief introduction for anybody interested in finding out more about Kallmann Syndrome and Hypogonadotrophic Hypogonadism and have been written by people who have Kallmann syndrome.

It is highly recommended that expert medical advice should be sought from health professionals specialising in developmental
endocrinology or reproductive endocrinology.

What is Kallmann syndrome?

Kallmann syndrome is a congenital hormonal condition characterised by the failure of an individual to enter puberty. It is a form of
hypogonadotrophic hypogonadism. The underlying cause is a failure in the communication pathways within the body that should operate in order to initiate puberty at the correct time. In particular it is a failure of communication between two structures inside the brain called the hypothalamus and the anterior pituitary gland. This failure of communication results in the sex organs or gonads (testes or ovaries) failing to maturing in the usual manner during puberty.

Why is it called Kallmann syndrome?

Franz Kallmann was a German born American scientist who published a paper in 1944 about the cases of 3 families who all had members who failed to enter puberty and had no sense of smell. He was the first person to propose that this was a genetic condition and it was named after him.

The first mention of the condition came in 1856 when a paper was published by Aureliano Maestre de San Juan highlighted an autopsy report on a patient with undeveloped sex organs and absent olfactory lobes (the part of the brain concerned with sense of smell). In Spanish-speaking parts of the world the condition is still called after him.

In 1954 de Morsier published a paper on 14 cases of anosmia (lack of sense of smell) and absent puberty and proved the neuro-pathological basis of the condition.

This has led to a number of different names being given to the same syndrome, depending on what part of the world you are in:

de Morsier’s Syndrome II;

Morsier-Gauthier Syndrome;

Kallmann-de Morsier Syndrome;

Maestre-Kallmann-de Morsier Syndrome;

Maestre de San Juan-Kallmann Syndrome;

Maestre de San Juan-Kallmann-de Morsier Syndrome;

When does puberty become ‘delayed’?

The age of onset of puberty can vary. It starts earlier in girls than in boys. Some specialists think it that if by the age of 13 for
girls and 15 for boys no signs of starting puberty then they should be referred to a specialist doctor, usually an endocrinologist.

In general any girl who has not had their first period or a boy showing any testicular development by the age of 15 should be
investigated for a delay of puberty by an endocrinologist.

In boys the testes should have descended in the scrotum before or just after birth. Un-descended testes (cryptorchidism) is a not an
uncommon event in boys and can be easily rectified with drugs or surgery. A history of bilateral cryptorchidism (both testes un-descended) should alert doctors to the possibility of a problem with puberty later, but this does not necessarily mean that a boy with cryptorchadism will develop Kallmann syndrome.

What does congenital mean?

Congenital means the condition is present from birth. It arises from the genetic make up you are born with. It means Kallmann syndrome cannot be caught or contracted during life.

What does hypogonadal mean?

‘hypo’ means below or under (as in hypodermic – below the skin). ‘gonadal’ means relating to the sex organs, i.e. the ovaries or testes. In this context the term implies that the sex organs have not developed into their normal state they would have achieved if puberty had occurred and are not responding in the usual post-pubertal manner in producing the normal sex hormones – oestrogen and testosterone.

The term hypogonadism covers a wide range of conditions and is not unique to Kallmann syndrome. There are more common genetic disorders that can result in hypogonadism such as Kleinfelter syndrome and Turner syndrome.

Hypogonadal conditions can be classed as either primary or secondary.

Primary hypogonadism is due to the sex organs themselves not functionally correctly or being unable to respond to the correct hormone signals. Kleinfelters and Turners are primary hypogonadism conditions. There are other primary hypogonadal conditions that can occur during life where previously normally functional gonads stop producing their specific hormones. Certain types of drugs, mumps and physical injury can all cause primary hypogonadism during life.

Secondary hypogonadism is due a failure in the communication pathways between the endocrine and nervous system with the sex organs resulting in them not developing correctly during puberty. Usually this means some sort of malfunction in two endocrine glands located within the brain called the hypothalamus and the pituitary. Kallmann syndrome and its related conditions are
secondary hypogonadism conditions.

There can be a wide number of reasons for hypogonadism so it s important to seek expert medical help. All the different conditions have different forms of treatment available.

What does hypogonadotrophic mean?

‘trophism’ means acting on or having an effect on. In this context the term hypogonadotrophic hypogonadism means that the sex organs have remained in their pre-pubertal state having not received the correct signals or inducement to under go the normal changes seen during puberty.

Kleinfelter syndrome in males and Turner syndrome in females are hypergonadotrophic disorders. They both still cause hypogonadism but the levels of circulating pituitary hormones are raised rather than lowered as seen
in Kallmann’s and other forms of hypogonadotrophic hypogonadism.

Are there other forms of hypogonadotrophic hypogonadism?

Yes. Hypogonadotrophic hypogonadism (which we will shorten to HH) covers a range of rare disorders that all result in the failure to enter puberty. Kallmann syndrome is a specific form of HH in which the individual has no sense of smell. There are other forms of HH where the sense of smell is present but are still very similar to Kallmann syndrome.

Is this distinction important?

Essentially, no it is not important as treatment for all types of HH is generally the same. Some people find the term Kallmann syndrome easier to remember and write so us it for all forms of HH.

Does it affect both men and women?

Yes. All forms of HH are seen in both men and women, even though it is more common in men. Current estimates suggest that Kallmann’s and HH is 3 to 5 times more common in men than women. The reason for the difference between the incidence in males and females is not fully understood.

How many people are affected?

Current estimates are that Kallmann’s occurs between 1 in 10,000 and 1 in 50,000 men and 1 in 70,000 women. It is a very rare condition that may well go under reported so a more accurate idea of the incidence may be difficult to establish. It is important that in any case of delayed puberty should be properly investigated by an endocrinologist to discover the underlying cause of the delay.

What is an endocrinologist?

An endocrinologist is a doctor who specialises in the treatment of hormonal disorders. An endocrinologist should be consulted so that they can fully investigate the causes of delayed puberty. There may be a number of reasons for the delay and might well be linked to other hormonal problems.

Kallmann’s and HH are hormonal disorders and usually need specialist help for the initial diagnosis and treatment. Endocrinology covers a wide field and if a choice were available it might be worth finding a doctor who specialises in reproductive endocrinology.

Is it curable?

Not at present. It is very difficult to cure a congenital disorder; most of the genetic research is focused on the fatal congenital
disorders such as cystic fibrosis.

Is it treatable?

Yes it is. It does depend on the type of KS or HH but it is treatable. The treatment will depend on the age of diagnosis mainly and a few other factors. The three major areas of treatment are:

Replacing the missing hormones

Fertility treatment

Reducing the risk of osteoporosis

Not all the symptoms are treatable. The lack of smell or anosmia seen in Kallmann’s is on the whole untreatable. Also while a person with KS can undergo most of the changes seen at puberty if diagnosed & treated early enough they will not go through a totally normal puberty and will still require specialised treatment if they are ever to become fertile.


  1. Nicky permalink

    Not bad and I think it’s a start

  2. Good read. 🙂

  3. Tracey permalink

    Helpful read 🙂

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