CTSK and pycnodysostosis: Other disorders to consider in the Differential Diagnosis of Cleidocranial Dysplasia (CCD) Spectrum Disorder are: mandibuloacral dysplasia (OMIM PS248370) [LMNA, ZMPSTE24 gene], pycnodysostosis [CTSK], Yunis Varon syndrome (OMIM 216340) [FIG4], hypophosphatasia [ALPL], and parietal foramina with cleidocranial dysplasia [MSX2].