Kallmann syndrome is a rare genetic hormonal disorder which is estimated to affect between 1 in 10,000 and 1 in 50,000 people. It is thought to be between two and three times more common in men than women.
People with Kallmann syndrome have a hormonal deficiency which prevents the individual from starting or fully completing puberty. Kallmann syndrome is also accompanied by a lack of sense of smell, known as anosmia.
Kallmann syndrome is a form of congenital hypogonadotropic hypogonadism (CHH) which can also be be described as isolated GnRH deficiency. It can occur with a normal sense of smell, it is only when the sense of smell is affected that the term Kallmann Syndrome is used.
Approximately 50% of cases of CHH are classed as Kallmann syndrome. Without treatment, people with Kallmann Syndrome will remain sexually underdeveloped with poorly defined secondary sexual characteristics and almost invariably infertile. Although most people have anosmia, a small minority have hyposmia, meaning that they have only a very weak sense of smell. It is very difficult to diagnose Kallmann syndrome for certain until puberty is reached.
However, it can sometimes be detected earlier in childhood when a child cannot smell through genetic testing or through hormone testing during mini-puberty in infants. Kallmann syndrome is more easily diagnosed in a teenager or adult who has failed to go through puberty and in whom an abnormal sense of smell is observed, but many are too embarrassed about their lack of sexual development and are nervous about visiting their GP or primary care physician. Consequently, there are probably many cases of Kallmann syndrome that go unreported.
More general information about congenital anosmia can be found here.
The diagnosis of Kallmann Syndrome may be suspected with evidence of lack of sexual maturation or hypogonadism, and evidence of incomplete sexual maturity by Tanner staging. This is an established method used by endocrinologists to evaluate the maturation of the primary and secondary sexual characteristics.
The diagnosis of Kallmann Syndrome additionally relies on hormone evaluation, as well as evaluation of the sense of smell (olfactory function testing). Analysis of the olfactory bulbs by an MRI scan can be useful, especially in young children. Genetic testing can also be used to diagnose the condition by identifying a disease-causing mutation in one of the genes responsible for Kallmann Syndrome.
Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centred information and are the driving force behind research and they can direct you to resources and services. Many organisations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by Fifth Sense.
Organisations/Websites/Social Media Networks Supporting this Disease
The information website for delayed or absent puberty (HYPOHH) website can be found here.
The Rare Connect Organisation is a European organisation that links together patient groups for rare conditions and allows patients to contact each other and access information.
The National Organisation for Rare Disorders is a US based organisation that focuses on patient information for rare disorders.
The Rare Disease UK group is a UK based organisation for patients with rare disorders and provides information and patient support.
Social Networking Websites
⦁ You can visit the following Facebook groups related to Kallmann syndrome:
Kallmann Syndrome & Hypogonadotropic Hypogonadism Community
- Further useful links:
- You can visit the following Facebook group to connect with other people with congenital anosmia:
Inclusion of these links does not indicate an endorsement