Over 30 genes have been identified in causing cases of Kallmann syndrome / CHH. There may be over 50 genes as new ones are discovered each year. Each of these genes have variants that can cause various additional physical symptoms alongside Kallmann syndrome / CHH.
These genes are normally inolved in the release of GnRH from the hypothalamus in some way, either by preventing the GnRH releasing nerve cells connecting with the hypothalamus or prevent the correct release of GnRH from the hypothalamus.
Picture: Dr Andrew Dwyer. Boston College, USA. 2019.
Picture: Dr Andrew Dwyer, Boston College, USA. 2019.
Genotype relates to the genes present in a person.
Phenotype relates to how these genes work in a person.
Two people may have the same gene present but other factors can cause the gene to act differently in each person which means they have different physical symptoms, or phenotype.
Even if a KS / CHH related gene variant is present or inherited it does not mean that the individual will have the physical symptoms of Kallmann syndrome / CHH; it depends on other environmental factors.