Examination of the bone reveals normal epiphyseal plates but disorganized metaphyseal regions.

[3] Physical irregularities often associated with Jansen's include: prominent or protruding eyes, a high-arched palate, micrognathia or abnormal smallness of the jaws – particularly the lower (mandible) jaw, choanal stenosis, wide cranial sutures and irregular formation of the long bones which can resemble rickets.

Individuals with JMC typically present with short stature, bowed legs, and widened growth plates.

[5] Diagnosis typically occurs during infancy or early childhood and is based around physical characteristics and symptoms.

X-rays may reveal abnormal development of the bulbous ends of the metaphyses of the limb bones.