Chromosome 4 (human)

Chromosome 4 (human) is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 4 spans more than 190 million base pairs (the building material of DNA) and represents approximately 6% of the total DNA in cells.

Structure

Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to genome annotation, the exact number of genes on each chromosome varies. Chromosome 4 is known to contain more than 1,000 genes, but the exact number is still under investigation. The structure of Chromosome 4 is crucial for its function, containing both genes that code for proteins and regions that have regulatory functions.

Genes

Among the genes located on Chromosome 4 are the Huntingtin gene (HTT), which is associated with Huntington's disease; the FGFR3 gene, mutations of which are known to cause achondroplasia, a form of short-limbed dwarfism; and the PKD2 gene, mutations in which lead to polycystic kidney disease. These genes play significant roles in the development and function of various bodily systems.

Genetic Disorders

Several genetic disorders are linked to mutations in genes on Chromosome 4. These include, but are not limited to:

- Huntington's disease: A progressive brain disorder caused by a single defective gene on Chromosome 4. This defect is dominant, meaning that anyone who inherits the defective gene from one parent will eventually develop the disease. - Achondroplasia: The most common form of dwarfism, caused by a mutation in the FGFR3 gene. - Polycystic kidney disease (Type 2): A condition characterized by the growth of numerous cysts in the kidneys, leading to enlarged kidneys and kidney failure in some cases. It is caused by mutations in the PKD2 gene. - Wolf-Hirschhorn syndrome: A condition caused by deletions in the short arm of Chromosome 4. It is characterized by distinctive facial features, growth delays, and intellectual disability.

Research

Research on Chromosome 4 continues to reveal new genes and their associated functions and disorders. Advances in genetic testing and gene therapy hold promise for diagnosing, treating, and potentially curing disorders linked to this chromosome.