Expanded phenotypic and hematologic abnormalities beyond bone marrow failure in MECOM-associated syndromes.

Area of Science:

• Genetics and Molecular Biology
• Hematology
• Developmental Biology

Background:

• The MECOM gene encodes critical protein isoforms for hematopoietic stem cell (HSC) self-renewal and maintenance.
• Germline MECOM variants are linked to congenital thrombocytopenia, radioulnar synostosis, and bone marrow failure.
• The phenotypic spectrum of MECOM-associated syndromes is expanding with the identification of novel pathogenic variants.

Purpose of the Study:

• To describe eight unrelated patients with novel MECOM variants, expanding the known phenotypes and genetic defects of MECOM-associated syndromes.
• To investigate potential genotype-to-phenotype correlations and the role of genetic modifiers in MECOM-associated disorders.
• To emphasize the importance of recognizing expanded clinical features for timely diagnosis and improved patient management.

Main Methods:

• Clinical characterization of eight unrelated patients presenting with diverse hematologic and non-hematologic features.
• Identification and analysis of unique MECOM variants in each patient.
• Review of existing literature on MECOM-associated syndromes and variants.

Main Results:

• Eight new cases contribute to the expanding spectrum of MECOM-associated syndromes, presenting unique MECOM variants.
• The series did not reveal a clear genotype-to-phenotype correlation, suggesting the influence of additional genetic modifiers.
• The study identified both previously known and novel hematologic and non-hematologic clinical manifestations associated with MECOM variants.

Conclusions:

• Recognition of the broadened clinical features of MECOM-associated syndromes is vital for rapid molecular diagnosis and early intervention.
• The lack of clear genotype-phenotype correlation suggests a complex interplay of genetic factors influencing disease presentation.
• Establishing a centralized, publicly accessible database for annotated MECOM variants is crucial for advancing clinical interpretation and functional studies.