BACKGROUND: Deletions in the long arm of chromosome 1 have been described in 
patients with a phenotype consisting primarily of obesity, intellectual 
disability and autism-spectrum disorder. The minimal region of overlap comprises 
two genes: DPYD and MIR137.
CASE PRESENTATION: We describe a 10-year-old boy with syndromic obesity who 
carries a novel 1p21.3 deletion overlapping the critical region with the MIR137 
gene only.
CONCLUSIONS: This study suggests that MIR137 is the mediator of the obesity 
phenotype of patients carrying 1p21.3 microdeletions.