A 7-year-old boy presents with short stature. His height is 2 standard deviations below the mean for his age. On clinical examination, he has normal proportions and no dysmorphic features. A hand-wrist X-ray is obtained for bone age assessment. The structure marked **A** in the diagram shows ossification of the capitate, hamate, triquetrum, lunate, trapezium, trapezoid, and scaphoid, but the pisiform remains cartilaginous. Which of the following is the most likely diagnosis?