Intermediate interstitial deletions of the long arm of chromosome 1 are typically associated with developmental delay and dysmorphic features. We describe the case of a 31-year-old male with intellectual disability, obesity and dysmorphic features, in whom array-comparative genomic hybridization identified a de novo 9.55 Mb deletion at 1q31.2q32.1. We discuss the genes encompassed within the deleted region; in particular, the implications of the deleted cancer-predisposing gene, CDC-73, and compare our clinical findings to other cases with similar deletions. The absence of microcephaly and growth retardation appears to differentiate more proximal interstitial 1q deletions from intermediate 1q deletions, and the presence of obesity is a newly reported phenotype within the 1q deletion spectrum. It is imperative that surveillance for CDC-73 related disorders, including parathyroid carcinoma, is considered in the management of interstitial intermediate 1q deletions.