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

LBR gene

The LBR gene encodes the lamin B receptor, a protein essential for cholesterol synthesis and the structural organization of the cell nucleus.

Normal Function

The LBR gene provides instructions for making a protein called the lamin B receptor. Different regions (domains) of this protein give it two distinct functions:

  • Sterol reductase function: One region, the sterol reductase domain, plays an important role in the synthesis of cholesterol. It performs chemical reactions that convert lanosterol to cholesterol. Cholesterol is vital for early development, cell membrane structure, myelin production, hormone synthesis, and bile acid production.
  • DNA-binding function: Another region, the DNA-binding domain, attaches to chromatin—the complex of DNA and proteins that packages DNA into chromosomes. Located in the nuclear envelope, this interaction helps maintain chromatin structure and may assist in DNA replication, gene regulation, and programmed cell death (apoptosis).

Health Conditions Related to Genetic Changes

Greenberg dysplasia

Several mutations in the LBR gene cause Greenberg dysplasia, a severe, fatal condition characterized by abnormal bone formation. Research suggests this is caused by the loss of the protein's sterol reductase function. Mutations may change single amino acids or lead to an abnormally short, nonfunctional protein. This disruption in cholesterol synthesis and the potential buildup of toxic byproducts are believed to interfere with normal growth and development.

Other disorders

Mutations in the LBR gene can also cause Pelger-Huët anomaly, a condition affecting the shape of the nucleus and the structure of chromatin in certain blood cells (granulocytes). In affected individuals, the nuclei have fewer segments than normal (hypolobulated) and the chromatin appears coarser. These mutations typically reduce the amount of functional protein, likely by impairing the receptor's DNA-binding domain.

Other Names for This Gene

  • DHCR14B
  • integral nuclear envelope inner membrane protein
  • lamin-B receptor
  • LBR_HUMAN
  • LMN2R
  • PHA
  • TDRD18

Frequently Asked Questions

Both conditions arise from different types of LBR variants. Missense or splice‑site mutations that partially reduce protein function usually cause Pelger‑Huët anomaly, a benign blood‑cell abnormality. Severe loss‑of‑function or truncating mutations that abolish sterol‑reductase activity produce Greenberg dysplasia, a lethal skeletal disorder. Sequencing the LBR gene identifies the exact mutation, allowing clinicians to predict the phenotype based on the mutation’s predicted impact.
Pelger‑Huët anomaly is typically asymptomatic and does not impair immune function or increase infection risk. No special hematologic monitoring is needed unless the individual has another blood disorder. However, the finding should prompt family screening because it indicates an inherited LBR variant.
First, confirm the specific mutation and its inheritance pattern (autosomal recessive). Offer carrier testing to at‑risk relatives, especially partners of carriers. Discuss reproductive options such as pre‑implantation genetic diagnosis, prenatal diagnostic testing, or use of donor gametes. Provide information on the differing outcomes of Pelger‑Huët anomaly (benign) versus Greenberg dysplasia (lethal) to aid informed decision‑making.
Ultrasound may reveal markedly shortened limbs, abnormal bone ossification, hydrops fetalis, and facial dysmorphism as early as the second trimester. Because the disorder results from a complete loss of cholesterol‑synthesizing activity, there is currently no effective in‑utero therapy, and the condition is uniformly fatal shortly after birth. Counseling focuses on recurrence risk (25 % for autosomal recessive) and options for future pregnancies.
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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