In addition, although it remains to be formally shown that activating mutations of PDGFRβ in osteoprogenitors contributes to osteopenia and occurrence of fractures in patients with Penttinen syndrome or Kosaki overgrowth syndrome (23), Scl-Ab could be useful to treat those pathological conditions. This evidence concerns the gene PDGFRB and skeletal overgrowth-craniofacial dysmorphism-hyperelastic skin-white matter lesions syndrome.