Background

Our body is composed of cells, each equipped with a nucleus housing our genetic information known as DNA. DNA serves as the hereditary material passed down from parents to children. While the hereditary material is largely similar among individuals, small variations exist. These variations contribute to the diversity in people’s appearances, potential abilities, and behaviors.

DNA is organized into 23 pairs of chromosomes, and each chromosome comprises a chain of specific genes. The arrangement of genes within chromosomes is consistent among all individuals. Within the DNA, there are thousands of genes, each playing one or several roles in human functioning. Only a portion of these genes has had their roles fully םר partially deciphered. Genes are identified by names, which consist of a sequence of English letters and numbers.

Each of our genes exists in two copies, with each copy inherited from one of our parents. As we are a blend of our parents’ hereditary material, we share some similarities with them while also possessing differences. Additionally, our distinct living conditions, which often vary significantly from those of our parents, contribute to further differences between us and them.

When an egg and a sperm are produced in our bodies, or unite to form an embryo, occasional spontaneous changes can occur in their genes. This phenomenon adds to the diversity in hereditary material across generations, potentially leading to entirely different traits in a child compared to their parents.

What role do genes play in our bodies? Genes act as a code. Following this code, the body knows how to create a variety of proteins. Each gene is capable of producing one or several different proteins. Proteins carry out all the work in our cells, constructing cell structures, generating additional proteins, and activating processes such as energy generation, substance creation, and cleaning.

Genes manifest themselves in our body in various ways. Certain genes are active exclusively in specific cells, while remaining inactive in others. Some genes carry out distinct functions across various cells and organs. Moreover, certain genes function at different life stages – during fetal development, childhood, and adulthood. Additionally, some genes operate at varying times of the month, corresponding to the women’s monthly cycle, or during different periods of the day, such as wakefulness and sleep.

We mentioned that each of our genes has two copies. Under normal circumstances, both copies function properly and play a role in cell activity. What happens if one of the copies is abnormal, resulting in the production of abnormal proteins, or if it fails to produce any protein at all?

In the body, there are functions for which it suffices for one copy of the gene to be normal. Even if the other copy doesn’t function well or doesn’t function at all, everything remains fine. The issue arises only when a person has two copies of the gene that are not functioning; then they may experience mild illness, severe illness, or be unable to survive. In such instances, the normal copy of the gene is termed dominant.

In the body, certain functions require two effective, functioning copies of the gene for optimal performance. If one of the copies fails to function adequately, resulting in insufficient production of normal protein, it impairs the body’s function. In such cases, the copies of the gene are referred to as recessive concerning a specific trait.

Moreover, a genetic disease may exhibit partial penetrance. In such cases, we observe that among individuals with an abnormal gene copy, the associated disease manifests in some but not all people. This occurrence may be attributed to the presence of other genes that potentially compensate for the abnormal function of the gene.

PRPF31 is the name of both a gene in human DNA and the protein it produces. This gene and protein have been widely recognized for their significance over an extended period. The PRPF31 protein plays a vital role in decoding genes and facilitating their transformation into proteins, requiring its continuous function in all cells throughout our body. Having one functional copy of the PRPF31 gene in the body is sufficient for maintaining a healthy life. Moreover, studies suggest that if the second copy is damaged, the resulting protein typically does not disrupt the normal functioning of the body.

In recent years, it has been discovered that retinal degeneration is linked to one copy of the PRPF31 gene being defective while the other functions well. In the entire body, having one normal copy of the gene is adequate, but for the proper function of the retina, it is insufficient. Therefore, retinal degeneration resulting from a mutation in the PRPF31 gene is considered dominant.

New studies have identified an additional function of the PRPF31 protein in the cells of the retina, linking it to the removal of byproducts generated during the vision process within the cell. When the PRPF31 protein is not present in sufficient levels in retinal cells, the cells are not effectively cleaned, leading to the accumulation of byproducts. Over time, this accumulation hinders cell function, eventually resulting in cell malfunction and, subsequently, cell death.

One hypothesis explaining the partial penetrance of the disease (meaning not everyone with a genetic defect in the PRPF31 gene will develop retinal degeneration) is that, for some individuals, having one functional copy of the gene is sufficient to generate enough protein for proper cell function. Additionally, similar to any disease, a person’s living conditions, including factors like diet, environment, stress levels, and more, can influence the progression of the disease.