Researchers ID Single-Gene Mutations That Lead to Atopic Dermatitis

Researchers have identified mutations in a gene called CARD11 that lead to atopic dermatitis.

The mutations were discovered in 4 unrelated families with severe atopic dermatitis.

The findings, published in the journal Nature Genetics, suggest that some of these defects could be potentially corrected by supplementation with glutamine.

Researchers at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), Bethesda, Maryland, analysed the genetic sequences of patients with severe atopic dermatitis and identified 8 individuals from 4 families with mutations in the CARD11 gene, which provides instructions for production of a cell-signalling protein of the same name.

While some people with these mutations had other health issues, such as infections, others did not, implying that mutations in CARD11 could cause atopic dermatitis without leading to other medical issues often found in severe immune system syndromes.

The researchers next set out to understand how the newly discovered CARD11 mutations contribute to atopic dermatitis. Each of the 4 families had a distinct mutation that affected a different region of the CARD11 protein, but all the mutations had similar effects on T-cell signalling.

With cell culture and other laboratory experiments, the researchers determined that the mutations led to defective activation of 2 cell-signalling pathways, one of which typically is activated in part by glutamine.

Growing cultured T cells from patients with CARD11 mutations with excess glutamine boosted mTORC1 activation, a key part of one of the affected pathways, suggesting the potential to partially correct the cell-signalling defects that may contribute to atopic dermatitis.

The researchers are now planning a study to assess the effect of supplemental glutamine and leucine, another amino acid that activates mTORC1, in people with atopic dermatitis with and without CARD11 mutations.

SOURCE: National Institutes of Health