Not getting the nod: The case against Yao syndrome

Area of Science:

• Genetics
• Immunology
• Autoinflammatory Diseases

Background:

• Yao syndrome, a NOD2-associated autoinflammatory condition, was first described in 2011.
• Over 30 publications and a case series of 152 individuals mention Yao syndrome, often linked to specific NOD2 variants (c.2717+158C>T and c.2023C>T;p.Arg675Trp).

Purpose of the Study:

• To critically evaluate the evidence linking NOD2 gene variants to the phenotypes described as Yao syndrome.
• To determine the clinical validity of Yao syndrome as a distinct diagnosis based on current scientific literature.

Main Methods:

• Review of existing literature on Yao syndrome and associated NOD2 variants.
• Analysis of population frequency data for cited NOD2 variants from databases like gnomAD.
• Assessment of the strength of evidence for a causal or susceptibility link between variants and phenotypes.

Main Results:

• Insufficient evidence currently links the broad phenotypes of Yao syndrome to specific NOD2 variants.
• The cited NOD2 variants (c.2717+158C>T and p.Arg702Trp) are highly prevalent in the general population (gnomAD), suggesting extremely low penetrance if any association exists.
• Large-scale association studies required to demonstrate a link have not been performed.

Conclusions:

• The existence of Yao syndrome as a distinct clinical entity is not supported by current evidence.
• Given the lack of robust scientific validation, the diagnosis of Yao syndrome should not be used in clinical practice.
• Further large-scale genetic association studies are needed to explore potential, albeit weak, links between common NOD2 variants and autoinflammatory phenotypes.