CAVIN1 and Osteopenia: Additional clinical features such as muscle mounding, muscle weakness, atlantoaxial instability, cardiac arrhythmias, osteopenia, distal metaphyseal deformation with joint stiffness, hypertrophic pyloric stenosis, and esophageal dysmotility can be highly suggestive of type 4 Berardinelli-Seip syndrome [22, 23], associated to variants in the PTRF gene.