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Can changes in the structure of chromosomes affect health and development?
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Mutationsanddisorders

Can changes in the structure of chromosomes affect health and development?

Structural changes to chromosomes can disrupt genes and the proteins they produce, potentially leading to issues with growth, development, and bodily function.

Structural changes can occur during the formation of egg or sperm cells, in early fetal development, or in any cell after birth. The effects depend on the size and location of the change, whether gene function is interrupted, and whether genetic material is gained or lost.

Types of Chromosomal Structural Changes

  • Translocations: Occur when a piece of one chromosome breaks off and attaches to another. It is balanced if no genetic material is gained or lost, and unbalanced if there is a gain or loss.
  • Deletions: Occur when a chromosome breaks and some genetic material is lost.
  • Duplications: Occur when part of a chromosome is abnormally copied, resulting in extra genetic material.
  • Inversions: Occur when a chromosome breaks in two places and the resulting piece of DNA is reversed and re-inserted. Pericentric inversions include the centromere, while paracentric inversions do not.
  • Isochromosomes: A chromosome with two identical arms (either two q arms or two p arms) instead of one of each, leading to extra copies of some genes and missing copies of others.
  • Dicentric chromosomes: Contain two centromeres resulting from the abnormal fusion of two chromosome pieces. These are unstable and often involve the loss of genetic material.
  • Ring chromosomes: Occur when a chromosome breaks in two places and the arms fuse together to form a circular structure, often resulting in the loss of genetic material near the ends of the chromosome.

Many cancer cells also exhibit changes in chromosome structure; these changes are not inherited and occur in somatic cells during the formation or progression of a tumor.

Frequently Asked Questions

Ring chromosomes form when both ends of a chromosome break and fuse together, often losing terminal genetic material. The loss of tumor suppressor genes or the gain of oncogenes on the ring can disrupt normal cell cycle control. In many cancers, ring chromosomes are seen as a marker of genomic instability and are associated with aggressive disease.===
balanced translocation means no genetic material is lost or gained, so carriers are usually healthy. However, during meiosis, the rearranged chromosomes can mis‑segregate, producing gametes with unbalanced genetic content. This increases the risk of miscarriages, congenital anomalies, or developmental disorders in offspring.
deletion removes one or more genes. If the lost genes are essential for brain development, growth, or organ formation, the individual may exhibit intellectual disability, growth retardation, or specific syndromic features. The severity depends on the size of the deletion and the functions of the affected genes.
n isochromosome has two identical arms (either two long q arms or two short p arms). This duplication of one arm and loss of the other changes the dosage of all genes on those arms. The resulting imbalance can cause overexpression of some genes and underexpression of others, leading to developmental abnormalities or predisposition to certain cancers.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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