Rare SH2B1 Gene Variants Linked to Neurodevelopmental Disorders and Metabolic Features
New Insights into SH2B1 Variants and Neurodevelopmental Disorders
Recent research has expanded understanding of how rare variants in the SH2B1 gene may contribute to neurodevelopmental disorders (NDDs) alongside metabolic symptoms such as obesity and hyperphagia. SH2B1 encodes a protein involved in regulating metabolism and body weight, but its role in neurodevelopmental conditions has been less clear.
Study Overview and Key Findings
A study published in Molecular Genetics & Genomic Medicine analyzed genetic and clinical data from five individuals with NDDs who carried rare monoallelic (single copy) variants in SH2B1. These individuals exhibited a range of symptoms including developmental delay, intellectual disability, autism spectrum disorder, distinct facial features, and increased appetite.
Whole-exome sequencing identified three missense variants (p.Leu18Val, p.Arg232Ser, p.Pro381Ser) and two truncating variants (p.Cys30Ter, p.Arg44LeufsTer30). Four variants occurred de novo (new mutations), while one missense variant (p.Arg232Ser) was inherited from the mother, who also showed elevated body mass index (BMI) and hyperphagia.
Functional Effects of SH2B1 Variants
Laboratory assays examined how these variants affected SH2B1 protein behavior. Truncating variants led to reduced protein expression and abnormal localization within cells, indicating loss of normal function. In contrast, missense variants maintained normal protein levels but altered cellular signaling pathways. Specifically, cells with these variants showed increased activation of the extracellular signal-regulated kinase (ERK) pathway in response to epidermal growth factor (EGF), suggesting changes in signaling dynamics that may impact neurodevelopment.
Implications for Diagnosis and Understanding
This research broadens the known clinical spectrum associated with SH2B1 variants, highlighting their potential contribution to both neurodevelopmental and metabolic phenotypes. The findings suggest that genetic testing for SH2B1 variants could be valuable in individuals with NDDs, especially when accompanied by metabolic symptoms like hyperphagia or obesity.
Considerations and Future Directions
While the study provides important insights, the small sample size and complexity of SH2B1 functions mean further research is needed to clarify how these variants influence neurodevelopment and metabolism. The observed effects on protein expression and signaling pathways offer clues but do not establish direct causation. Clinicians and researchers should interpret these findings cautiously and in the context of comprehensive clinical evaluation.
For more detailed information, see the original study published at PubMed.
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