What is the Difference Between PKD1 and PKD2

PKD1 and PKD2 are two genes that encode for two important proteins in kidney function called polycystin-1 and polycystin-2. The mutations of PKD1 and PKD2 genes cause autosomal dominant polycystic kidney disease (ADPKD), which is the most common cause of renal failure worldwide. ADPKD leads to renal cyst formation, kidney enlargements, and extrarenal organ involvement, such as the liver, heart, pancreas, and brain. 78% of patients with ADPKD have PKD1 gene mutations, 15% have the PKD2 gene mutation, and about 1% have GANAB gene mutations. PKD1 and PKD2 genes are two genes that encode for two important proteins in kidney function called polycystin-1 and polycystin-2. These two proteins interact to regulate cells in the kidneys and liver. They are also a part of the process of forming tubular structures and influencing the growth and function of fluid secretion.

The key difference between PKD1 and PKD2 is the genes they code for. PKD1 is a gene that codes for a protein called polycystin-1 while PKD2is a gene that codes for a protein called polycystin-2.

CONTENTS

1. Overview and Key Difference
2. What is PKD1  
3. What is PKD2
4. Similarities – PKD1 and PKD2
5. PKD1 vs PKD2 in Tabular Form
6. Summary – PKD1 vs PKD2
7. FAQ: PKD1 and PKD2

What is PKD1?

PKD1 gene is located on chromosome 16p13. It provides instructions for making a protein called polycystin-1 (PCI). This protein (4302 amino acid protein) is most active in kidney cells before birth and it is less active protein in normal adult kidneys. Polycystin-1 can interact with somewhat smaller protein called polycystin-1. PC1 mediates mechanosensation of fluid flow by the primary cilium of kidney cells. 78% of cases of autosomal dominant polycystic kidney disease (ADPKD) is caused by PKD1 gene mutation.

Furthermore, most people with PKD1 mutations have kidney failure by the age of 70 years. Therefore, mutations of PKD1 gene typically signify a severe clinical phenotype of ADPKD.

Figure 01: PKD1 and PKD2

What is PKD2?

The PKD2 gene is located in chromosome 4q22.1, and it provides instructions for making a protein called polycystin-2 (PC2). This protein (968-amino acid protein) is found in the kidneys before birth and in many adult kidney tissues too. Polycystin 2 protein interacts with proteins such as TRPC1, polycystin-1, and TNNI3. Polycystin 2 plays an important function in kidney cell survival.

PKD2 accounts for around 15% of ADPKD cases. Furthermore, 50% of individuals with PKD2 mutations still have adequate kidney function by the age of 70 years. Therefore, the mutations of the PKD2 gene typically signify a milder clinical phenotype of ADPKD.

Similarities Between PKD1 and PKD2

1. PKD1 and PKD2 genes are two genes that encode for two important proteins in kidney function called polycystin-1 and polycystin-2.
2. The interaction of proteins made by PKD1 and PKD2 genes in renal tubules promotes the normal development and function of the kidneys.
3. The mutations of PKD1 and PKD2 genes cause autosomal dominant polycystic kidney disease (ADPKD).
4. Mutations in these two genes account for many cases of autosomal dominant polycystic kidney disease.

Difference Between PKD1 and PKD2

Definition

1. PKD1 is a gene that encodes for a 4302 amino acid protein called polycystin-1.
2. PKD2 is a gene that encodes for a 968 amino acid protein called p polycystin-2.

Location

1. PKD1 is located in 16p13.
2. PKD2 is located in 4q22.1.

Gen Product Function

1. PKD1 gene encodes for PC1, which mediates mechanosensation of fluid flow by the primary cilium of kidney cells.
2. PKD2 gene encodes for PC2, which plays an important role in kidney cell survival.

Mutation in the Gene

1. 78% of cases of autosomal dominant polycystic kidney disease (ADPKD) are caused by PKD1 gene mutation.
2. 15% of cases of autosomal dominant polycystic kidney disease (ADPKD) are caused by PKD2 gene mutation.

Influence on ADPKD Disease Severity

1. The mutations of the PKD1 gene typically signify a severe clinical phenotype of ADPKD.
2. The mutations of the PKD2 gene typically signify a milder clinical phenotype of ADPKD.

The following table summarizes the difference between PKD1 and PKD2.

Summary – PKD1 vs PKD2

PKD1 encodes for a protein called polycystin-1 whilePKD2 encodes for a protein called polycystin-2. Furthermore, PKD1 is located in chromosome 16 whereas PKD2is located in chromosome 4. This is the summary of the difference between PKD1 and PKD2.

FAQ: PKD1 and PKD2

1. What is ADPKD caused by?

• ADPKD is caused by a genetic fault that interrupts the normal development of some cells in the kidneys and leads to cysts development. Faults in 1 of 2 different genes are said to cause ADPKD: PKD1 mutation and PKD2 mutation.

2. What is the available treatment for ADPKD?

• Tolvaptan therapy may be recommended currently for adults at risk of rapidly progressive ADPKD. Tolvaptan is a pill that people can take by mouth, which helps to slow the rate of kidney cyst growth and the decline of kidney function.

3. What chromosome is PKD1 on?

• The polycystic kidney disease 1 gene encodes a 14 kb transcript and lies within a duplicated region on chromosome 16. The exact location of the PKD1 gene is 16p13.

4. What does PKD1 gene code for?

• The PKD1 gene provides instructions for making a protein called polycystin-1. Moreover, this protein is most active in kidney cells before birth and less active in normal adult kidneys. Polycystin-1 mediates the mechanosensation of fluid flow by the primary cilium of kidney cells.

5. What does the PKD2 gene do?

• PKD2 gene makes a protein called polycystin-2 (PC2). PC2 acts in the plasma membrane, primary cilium and endoplasmic reticulum. PC2 plays an important function in kidney cell survival.

Reference:

1. “Pkd2 Gene.” MedlinePlus, U.S. National Library of Medicine.
2. “PKD1 Polycystin 1, Transient Receptor Potential Channel Interacting [Homo Sapiens (Human)] – Gene – NCBI.” National Center for Biotechnology Information, U.S. National Library of Medicine.

Image Courtesy:

1. “PKD1PKD2 en” By Kuebi = Armin Kübelbeck – Own work (CC BY-SA 3.0) via Commons Wikimedia

Related posts:

What is the Difference Between Sarcoptic and Demodectic Mange What is the Difference Between Peripheral and Central Cyanosis What is the Difference Between African and American Trypanosomiasis What is the Difference Between Tetanus and Strychnine Poisoning What is the Difference Between RSV and Influenza