A five-year-old girl with global developmental delay and mild dysmorphic features was referred for karyotyping. Cytogenetic analysis identified an interstitial deletion in the approximate position of chromosome band 10q23.1. The patient's DNA was analysed using an Affymetrix SNP6.0 array, and a 7.46Mbp deletion was detected within the region 10q22.3-q23.32. The deletion encompasses the BMPR1A gene, but does not extend as far as the phosphatase and tensin homolog (PTEN) locus. The location and extent of the deletion is the first of a small group of 10q deletion patients, which has been characterised at the level of resolution afforded by a SNP6.0 chip. Essentially, this case confirms that patients with microdeletions in the 10q23 region can be further divided into three sub-classes, depending on whether the deletion encompasses the BMPR1A gene, the PTEN gene or both.