Mutations in the Trps1 gene lead to the human condition tricho‐rhino‐phalangeal syndrome which is characterised by craniofacial and skeletal dysplasias and siRNA mediated knockdown of Trps1 in a pre‐odontoblastic cell line leads to the suppression of Phospho1, Alpl and Smpd3 expression.48 The gene discussed is SMPD3; the disease is skeletal dysplasia.