Lipoid proteinosis
Lipoid proteinosis is a rare genetic condition characterized by the accumulation of protein deposits in various tissues, leading to skin scarring, voice changes, and neurological symptoms.
Overview
Lipoid proteinosis results from the formation of small clumps of proteins and other molecules in tissues throughout the body, including the skin, mucous membranes, and internal organs. The condition is also known as Urbach-Wiethe disease.
Symptoms
Symptoms often appear in infancy and can include:
- Voice abnormalities: Hoarseness caused by deposits in the vocal cords; in infants, this manifests as a weak cry.
- Skin and mucous membranes: Fragile skin that blisters and scars after minor trauma. Deposits can cause skin to thicken and turn yellowish, particularly in areas of friction like the elbows and knees.
- Oral features: A thick, shortened tongue and deposits in the throat and tonsils, which may cause breathing difficulties.
- Eye features:Moniliform blepharosis, which are tiny, bead-like bumps lining the eyelids.
- Neurological features: Some individuals experience seizures (epilepsy), memory loss, or behavioral changes, thought to be linked to calcium deposits (calcification) in the temporal lobes of the brain.
Causes
The condition is caused by mutations in the ECM1 gene. This gene provides instructions for the ECM1 protein, which is found in the extracellular matrix—the lattice that provides structural support between cells. A lack of functional ECM1 protein leads to an unstable extracellular matrix. This instability is believed to cause neighboring cells to overproduce proteins, which then accumulate as the characteristic deposits seen in lipoid proteinosis.
Inheritance
Lipoid proteinosis is inherited in an autosomal recessive pattern. This means that both copies of the ECM1 gene in each cell must have mutations for the condition to occur. Parents of an affected individual each carry one copy of the mutated gene but typically do not exhibit symptoms themselves.