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ORC4 gene

Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

ORC4 gene

The ORC4 gene provides essential instructions for creating a protein involved in DNA replication and the maintenance of chromosome structure.

Normal Function

The ORC4 gene provides instructions for making a protein that is important in the copying of a cell's DNA before the cell divides, a process known as DNA replication. The protein produced from this gene, ORC4, is one of a group of proteins known as the origin recognition complex (ORC). This complex is made up of proteins ORC1 through ORC6.

The ORC attaches to specific regions of DNA called origins of replication, where DNA copying begins. This complex attracts additional proteins to form a pre-replication complex. When this complex is attached to the origin, replication can begin. This tightly controlled process, called replication licensing, ensures that DNA replication occurs only once per cell division, which is required for cells to divide.

Additionally, the ORC attaches to a form of DNA called heterochromatin. This is densely packed DNA that contains few functional genes but is vital for controlling gene activity and maintaining the structure of chromosomes.

Health Conditions Related to Genetic Changes

Meier-Gorlin syndrome

Mutations in the ORC4 gene cause Meier-Gorlin syndrome, a condition characterized by short stature, underdeveloped kneecaps, and small ears. These mutations alter the ORC4 protein, typically by changing single amino acids or leading to the production of an abnormally short version of the protein.

The most common mutation replaces the amino acid tyrosine at position 174 with cysteine (Tyr174Cys). These changes impair the assembly of the pre-replication complex, which disrupts replication licensing. Researchers speculate that this reduction delays the cell division process, slowing the growth of bones and other tissues during development.

Other Names for This Gene

  • HsORC4
  • ORC4_HUMAN
  • ORC4L
  • ORC4P
  • origin recognition complex, subunit 4
  • origin recognition complex, subunit 4 homolog

Frequently Asked Questions

Meier‑Gorlin syndrome due to ORC4 mutations follows an autosomal‑recessive pattern, meaning both parents must carry one altered copy of the gene. Each pregnancy has a 25 % chance of producing an affected child, a 50 % chance of a carrier child, and a 25 % chance of a child with two normal copies.
Yes. If the specific pathogenic ORC4 variant has been identified in the family, chorionic villus sampling (around 11‑13 weeks) or amniocentesis (after 15 weeks) can be used for targeted molecular testing. Discuss the procedure, risks, and timing with a maternal‑fetal medicine specialist.
Growth hormone therapy has been tried in some patients, but results are variable and not guaranteed. A pediatric endocrinologist can assess growth velocity, bone age, and potential benefits versus side‑effects before initiating treatment.
lthough the primary features are developmental, any sudden worsening of growth, new neurologic symptoms (headaches, seizures), or signs of bone fragility (frequent fractures) should be evaluated promptly, as they may indicate complications related to impaired cell division or secondary issues.
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.