It is the third in size and is related to the sense of smell and inflammatory processes. Related disorders are:

Facioscapulohumeral Muscular Dystrophy is a muscular disorder caused by a disorder in the D4Z4 region in the arm q; causing weakness and atrophy of the muscles. The condition affects the muscles of the face, arms, and shoulders.

Wolf-Hirschhorn is a complex syndrome caused by the suppression of genetic material in a region called 4p16.3 on the short arm of chromosome 4. The deleted part contains the dominant genes required for the normal increase in development; Therefore, Wolf-Hirschhorn syndrome is characterized by intellectual disability, facial abnormalities.

Chromosome 4 abnormalities are also associated with cancers such as Multiple myeloma leukemia. The displacement or alteration of genes are responsible for the development of these cancers. Chronic eosinophilic leukemia associated with PDGFRA is caused by changes in the PDGFRA gene, which is located on chromosome 4. This condition is characterized by an increase in the number of eosinophils, which are a type of white blood cell involved in allergic reactions.