What causes Polycystic Kidney Disease ?
A gene mutation, or defect, causes polycystic kidney disease. Genes provide instructions for making proteins in the body. A gene mutation is a permanent change in the deoxyribonucleic acid (DNA) sequence that makes up a gene. In most cases of PKD, a person inherits the gene mutation, meaning a parent passes it on in his or her genes. In the remaining cases, the gene mutation develops spontaneously. In spontaneous cases, neither parent carries a copy of the mutated gene.
                
Researchers have found three different gene mutations associated with PKD. Two of the genes are associated with autosomal dominant PKD. The third gene is associated with autosomal recessive PKD. Gene mutations that cause PKD affect proteins that play a role in kidney development.
                

                
Genetic Disorders   Each cell contains thousands of genes that provide the instructions for making proteins for growth and repair of the body. If a gene has a mutation, the protein made by that gene may not function properly, which sometimes creates a genetic disorder. Not all gene mutations cause a disorder.   People inherit two copies of most genes; one copy from each parent. A genetic disorder occurs when one or both parents pass a mutated gene to a child at conception. A genetic disorder can also occur through a spontaneous gene mutation, meaning neither parent carries a copy of the mutated gene. Once a spontaneous gene mutation has occurred, a person can pass it to his or her children.   Read more about genes and genetic conditions in the U.S. National Library of Medicines (NLMs) Genetics Home Reference.