Kallmann syndrome

How is Kallmann syndrome diagnosed?

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. Tanner staging is an established method used by endocrinologists worldwide 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 MRI 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.

Last updated on 05-01-20

How is Kallmann syndrome inherited?

Kallmann syndrome (KS) may be inherited in an X-linked recessive, autosomal dominant, or autosomal recessive manner depending on the responsible gene. For example:

  • KS due to mutations in the KAL1 gene (also called the ANOS1 gene), causing Kallmann syndrome 1, is inherited in an X-linked recessive manner.
  • KS due to mutations in the FGFR1 , PROKR2 , PROK2 , CHD7 or FGF8 genes (causing KS types 2, 3, 4, 5 and 6, respectively) is usually inherited in an autosomal dominant manner.
  • KS due to mutations in PROKR2 and PROK2 can also be inherited in an autosomal recessive manner.

The majority of people with KS have a negative family history (the condition occurs sporadically). However, affected people are still at risk to pass the responsible mutation(s) on to their children, or to have an affected child. The risk for each child to be affected depends on the genetic cause in each case, and may be up to 50%.

People with personal questions about the genetic cause and inheritance of KS are encouraged to speak with a genetic counselor or other genetics professional. The genetic cause in many cases remains unknown, and a thorough family history should be obtained to understand the mode of inheritance in each family and to aid in genetic testing and counseling. Information about whether specific features are present in all family members can help determine the mode of inheritance.

Last updated on 05-01-20

Selected Full-Text Journal Articles

Kallmann syndrome - articles

Costa-Barbosa FA, Balasubramanian R, Keefe KW, Shaw ND, Al-Tassan N, Plummer L, et al. Prioritizing Genetic Testing in Patients With Kallmann Syndrome Using Clinical Phenotypes. J Clin Endocrinol Metab. 2013 May; 98(5):E943-E953.

Last updated on 04-27-20

Name: Hormone Health Network United States Toll Free: 1-800-HORMONE (1-800-467-6663) Email: hormone@endocrine.org Url: https://www.hormone.org
Name: The Pituitary Foundation 86 Colston Street Bristol BS1 5BB
United Kingdom
Phone: 0117 370 1320 Email: helpline@pituitary.org.uk Url: https://www.pituitary.org.uk/
Name: GNRH Network COST European Cooperation in Science and Technology ACTION BM1105
CH - 1011 Lausanne
Vaud, Switzerland
Url: http://www.gnrhnetwork.eu/hhn_home/hhn-patients_familles_gnrh_deficiency_kallmann_syndrome.htm

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The RareGuru disease database is regularly updated using data generously provided by GARD, the United States Genetic and Rare Disease Information Center.

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