One study specifically described several de novo missense mutations in FGFR2 that for perinatal lethal skeletal dysplasia, termed the BBDS-FGFR2 type, characterized by multiple bone deformities, including impaired mineralization of the calvarium, craniosynostosis, and dysmorphic facial features, as well as long bone deformities and osteopenia [18]. The gene discussed is FGFR2; the disease is Osteopenia.