There are three ways that Kallmann Syndrome is usually inherited: autosomal recessive, autosomal dominant, and x-linked.
Autosomal recessive: This means a person must have two changed copies of the gene, one from mom and one from dad, in order to have the disorder. Usually, we have two copies of every gene, one from each parent. In an autosomal recessive condition, if only one gene is changed, the person is considered a ‘carrier’. Carriers typically show no symptoms since the other copy of the gene is functioning normally. When two carriers have a child, there is a chance they could each pass on their changed copy. That child would then have no functioning copies of the gene, and therefore have the disorder.
Autosomal dominant: this means that a person only needs one copy of the gene to be changed in order to have Kallmann Syndrome. This is different than autosomal recessive. With an autosomal dominant disorder one changed gene is enough to cause symptoms. This could be inherited from one parent, or this could be a brand new change in that person.
X-linked: This means that the gene is on the X-chromosome. Females have two X chromosomes, and men have one X chromosome and one Y chromosome. In cases of X-linked inheritance, women must inherit 2 copies of the gene, one on each X, in order to have Kallmann Syndrome. Since men only have one X-chromosome, they only need to inherit one copy of the gene in order to have the syndrome.
Kallmann Syndrome can also be inherited in an “oligogenic” fashion, which means that multiple genes interacting with each other cause the disorder. Sometimes, Kallmann Syndrome can be sporadic, which means there is no gene change that can be found.
The way Kallmann syndrome is inherited depends on the gene. Each gene has a specific way of being inherited depending upon which chromosome it is found. Check with your doctor or genetic counselor for more information on your specific gene change.
Other Questions About Kallman syndrome/hypogonadotropic hypogonadism
- Would a pituitary gland replacement be a cure for Kallman syndrome?
- Why does Kallmann Syndrome affect more males than females?
- Why can people with Kallmann Syndrome have reduced bone density?
- Who else in my family should I test for Kallmann Syndrome?
- Where do I find other people with Kallmann Syndrome ?
