Severe Thrombocytopenia and Facial Asymmetry in a Mexican Patient with Noonan Syndrome-Like Disorder with Loose Anagen Hair: Clinical Observations and Diagnostic Considerations.

Abstract

Introduction: Noonan syndrome-like disorder with loose anagen hair 1 is a rasopathy caused by pathogenic variants in the SHOC2 gene, characterized mainly by short stature, facial dysmorphisms and ectodermal alterations.

Case presentation: This case describes an 18-year-old female with the pathogenic variant c.4A>G in SHOC2, severe thrombocytopenia and facial asymmetry, features not currently considered part of the phenotype. While thrombocytopenia may be associated with the SHOC2 variant, a direct causal relationship cannot be definitively established, and the possibility of coexisting autoimmune disorders, such as systemic lupus erythematosus, could not be excluded.

Conclusion: This case underscores the importance of early molecular diagnosis and comprehensive hematological monitoring in patients with rasopathies, highlighting the potential for life-threatening complications. Systematic reviews involving larger cohorts are needed to better define the clinical spectrum of NSLH1 and refine management strategies for potential complications.