ACAN-related disorder may present as a non-syndromic cause of short stature or a skeletal dysplasia. Advanced bone age is considered its unique characteristic. Our study investigated four paediatric and five adult patients across four affected families, possessing two previously reported and two novel ACAN variants. Of the children, one presented before birth with shortened long bones on ultrasound; the others after birth with short stature and normal hormone tests. Bone ages were either delayed (n=3) or advanced (n=1). Detailed radiograph analysis identified hypochondroplasia-like spine changes with loss of widening of the spinal pedicles which was more prominent in adults, and a shortened fourth finger in four patients. These results show bone age is not always advanced in this condition. (https://jmg.bmj.com/content/early/2026/04/09/jmg-2025-111354 )