TBX6 and Cowden syndrome 1: In contrast, our screening of known disease genes for CS and vertebral malformation could only find the causal genes in <10% of nonsyndromic CS patients who had no major comorbidities; CS in our cohort did not have the mutations in known genes causing CS and SCD other than TBX6 and LNFG. CS is a very heterogeneous disorder; the type, location, number of vertebral malformations, and comorbidities are different between the patients (Giampietro et al., 2013).