GH1 and pycnodysostosis: A few studies show that growth hormone therapy has a beneficial effect on skeletal dysplasia patients with severe short stature (-3 SD to -4 SD), such as tricho-rhino-phalangeal syndromes and pycnodysostosis.[15–17] Our X-linked SEDT patient achieved inspiring 2.1 cm height gain in the 3-month rhGH treatment with a dosage equivalent to idiopathic short stature patients.