The genetic aetiology includes compound heterozygous mutations of WDR35 and of another IFT encoding gene, namely, IFT140. More specifically, the phenotype associated with IFT140 mutations (SRTD9), was recently reported to include sagittal and metopic CS as part of the observed skeletal malformations [93]. The gene discussed is IFT140; the disease is short-rib thoracic dysplasia 9 with or without polydactyly.