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LTBP4 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

LTBP4 gene

The LTBP4 gene provides instructions for creating a protein essential for connective tissue integrity and the regulation of growth factor activity.

Normal Function

The LTBP4 gene provides instructions for making a protein that has multiple functions in the extracellular matrix, which is the intricate lattice of proteins and other molecules that forms in the spaces between cells. The LTBP4 protein controls the activity of a protein called transforming growth factor beta-1 (TGFβ-1) by attaching it to the extracellular matrix. This growth factor is turned off (inactivated) when stored in the extracellular matrix and turned on (activated) when released. When turned on, the TGFβ-1 protein triggers chemical signals that direct the functions of the body's cells during growth and development and that regulate the formation of the extracellular matrix.

The LTBP4 protein also plays a critical role in the formation of elastic fibers in the extracellular matrix. Elastic fibers are slender bundles of proteins that provide strength and flexibility to connective tissue, which supports organs and tissues such as the skin, lungs, heart, ligaments, and blood vessels.

Health Conditions Related to Genetic Changes

Cutis laxa

At least 20 variants (also known as mutations) in the LTBP4 gene have been identified in people with cutis laxa. LTBP4 gene variants cause a form of the disorder called autosomal recessive cutis laxa type 1C (ARCL1C) or Urban-Rifkin-Davis syndrome, which is characterized by loose and sagging skin, a lung disease called emphysema, and abnormalities involving the digestive and urinary systems.

Most of the LTBP4 gene variants involved in cutis laxa change single DNA building blocks. These changes alter the blueprint for making proteins, and the abnormal blueprint is broken down in the cell before LTBP4 protein is made. A shortage of this protein prevents the assembly of elastic fibers, which weakens connective tissue in the skin, lungs, and other organs. These defects in connective tissue underlie the major features of ARCL1C.

Other Names for This Gene

  • FLJ46318
  • FLJ90018
  • LTBP-4
  • LTBP-4L

Genomic Location

The LTBP4 gene is found on chromosome 19.

Frequently Asked Questions

Key complications include progressive pulmonary emphysema leading to breathing difficulties, gastrointestinal issues such as hernias or malabsorption, urinary tract anomalies, and cardiovascular problems like aortic dilation. Regular pulmonary function tests, abdominal imaging, renal ultrasounds, and cardiac echocardiograms are advised at least annually.
No curative therapy exists for the underlying elastic‑fiber defect. Skin care focuses on moisturizers, gentle handling, and protective clothing to avoid trauma. Surgical correction may be considered for severe redundant skin or hernias, but outcomes are variable. Research into TGF‑β modulation is ongoing but not yet clinically available.
LTBP4‑related cutis laxa is inherited in an autosomal recessive manner. Both parents carry one pathogenic variant. Each pregnancy carries a 25 % risk of an affected child, a 50 % chance of a carrier child, and a 25 % chance of an unaffected, non‑carrier child. Carrier testing of siblings and prenatal or pre‑implantation genetic diagnosis can be discussed with a genetic counselor.
Testing is typically performed via next‑generation sequencing of a targeted connective‑tissue panel or whole‑exome sequencing using a blood sample from the patient. For prenatal testing, chorionic villus sampling (10‑12 weeks) or amniocentesis (15‑18 weeks) can provide fetal DNA for targeted LTBP4 analysis if the familial mutations are known.
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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