RAB23 regulates growth factor signaling (Eggenschwiler et al., 2001; Fuller et al., 2014; Hasan et al., 2020), and mutations in RAB23 affect the development and patterning of multiple organs and give rise to a diverse complex congenital anomaly, collectively known as Carpenter syndrome (CS, MIM# 201000) or acrocephalopolysyndactyly type II (Carpenter, 1909; Jenkins et al., 2007). This evidence concerns the gene RAB23 and Cowden syndrome 1.