Laryngo-Onycho-Cutaneous Syndrome

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Laryngo-onycho-cutaneous (LOC) syndrome is a disorder that leads to abnormalities of the voicebox (laryngo-), finger- and toenails (onycho-), and skin (cutaneous). Many of the condition's signs and symptoms are related to the abnormal growth of granulation tissue in different parts of the body. This red, bumpy tissue is normally produced during wound healing and is usually replaced by skin cells as healing continues. However, in people with LOC syndrome, this tissue grows even when there is no major injury.

LOC syndrome is caused by mutations in the LAMA3 gene, which provides instructions for making one part (subunit) of a protein called laminin 332. This protein is made up of three subunits, called alpha, beta, and gamma. The LAMA3 gene carries instructions for the alpha subunit; the beta and gamma subunits are produced from other genes.

LOC syndrome is a rare disorder that primarily affects families of Punjabi background from India and Pakistan, although the condition has also been reported in one family from Iran.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Published Date: September 01, 2014
Published By: National Institutes of Health