Some kidney diseases have a genetic cause, find out more about what genetic information/genes are and how heredity works here. 


What are genes, DNA and chromosomes?

The human body is made up of millions of cells. Most cells contain a complete set of genes.


Genes are the “recipe of life” acting as a set of instructions controlling our growth and the functioning of our body. They are responsible for many of our characteristics, such as eye color or body height. 
When a gene mutation occurs, the protein product may be defective, ineffective, or absent. Depending on the function of the particular protein, this may affect a single or several organ systems.


Genes are made up of a chemical called DNA and are located inside filamentous structures called chromosomes.
Each person has 46 chromosomes in most cells. These are 22 pairs of autosomal chromosomes and 1 pair of sex chromosomes, i.e. X and Y.  Chromosomes are inherited from parents, 23 from the mother and 23 from the father, so each person has 2 full sets of 23 chromosomes or 23 "pairs". Because chromosomes are made of genes, everyone inherits 2 copies of most genes, one copy from each parent. The situation is slightly different in the case of sex chromosomes, where in case of male gender there is one X and Y chromosome and in case of female gender two X chromosomes, respectively.


In biology, the term inheritance refers to the passing on of characteristics or traits from parents to their offspring. Every living being inherits characteristics from its parents through genetic material (DNA/chromosomes) that is passed on through reproduction.

Think of it like this: When a baby is born, it receives some traits from its mother and some from its father. These traits can be anything from eye colour, hair texture or even susceptibility to certain diseases. In biology, we call this passing on of traits from one generation to the next genetics.

Studying inheritance helps us to understand how traits are passed on, how they differ from individual to individual and how new traits can arise through the process of evolution.

A distinction is made between different types of inheritance, which are explained in more detail below. 

Autosomal Inheritance

This type of inheritance affects genes that are located on autosomal chromosomes, i.e. are not sex-specific.

Autosomal Recessive

In recessive inheritance, a correct version of the gene prevents the disease from manifesting, i.e. two defective genes are required for the disease to manifest. For an autosomal recessive disease to occur, a child must inherit two mutated or defective copies of the gene (two gene alleles), one from each parent. If only one mutated or defective allele is inherited, the child does not have the disease but is a carrier of the disease/mutation. In a family in which both parents are carriers of the mutation, there is a 25% risk of the parents' children also developing the disease. Both sexes are equally affected.
Examples for autosomal recessive inheritance are diseases such as Bardet-Biedl syndrome, primary hyperoxaluria type 1 or autosomal recessive polycystic kidney disease (ARPKD).

Autosomal Dominant

In dominant inheritance, one copy of the defective gene is sufficient to trigger the symptoms of the disease. This means that if a gene is inherited dominantly from the parents, around 50 % of the offspring will also be affected.

For example, in autosomal dominant inheritance, if a child receives one normal and one abnormal gene from the parents and the abnormal gene is dominant, it will overwhelm the normal gene. As a result, the possession of a single abnormal gene is sufficient to develop the disease. This phenomenon is observed in diseases such as Marfan syndrome, neurofibromatosis type 1 and HNF1B nephropathy.



Digenic Inheritance

Digenic inheritance means that a mutation in two different genes causes a characteristic or a disease. It's like having two keys that need to be turned at the same time to open a door. In this case, both mutated genes must be present for the condition or disease to appear. If only one of the genes is mutated, the condition or disease may not be noticed, as both mutations must be active. This type of inheritance is even more complex as it involves interactions between two different genes and not just one.