during neural development. Agenesis or hypoplasia of the corpus callosum and cerebellum have been found in at least one living affected individual and several who did not survive to term. Hydrocephalus occurred in one living individual 9 months after birth and in four who did not survive to term. Hydrocephalus was also observed in zebrafish whose CENPF genes were experimentally knocked out. Cerebellar hypoplasia in association with hydrocephalus can constitute Dandy–Walker malformation, which is found in a number of other ciliopathies, sometimes together with agenesis of the corpus callosum. Physical features Physical features are variable but usually include short stature, large, low-set ears, a high nasal bridge, a small jaw and a large mouth. Some of those affected have had epicanthal folds or fine, sparse hair. One individual was reported to have been born with a skin tag on the left cheek. Four affected individuals who did not survive to term had cleft palate. Heart A minority of those affected have been born with an atrial septal defect, a type of congenital heart defect. One affected individual was reported to have a ventricular septal defect and neonatal peripheral oedema in the legs. Two individuals who did not survive to term had a patent foramen ovale, a specific type of atrial septal defect, as well as reduced heart muscle tissue (myocardium) and abnormally small heart muscle cells (cardiomyocytes). Skeletal One affected individual was reported to have had hip dysplasia, leading to dislocation, and another was reported to have metopic craniosynostosis, leading to a metopic ridge. Two individuals who did not survive to term had polydactyly of the thumb (preaxial polydactyly), flattened vertebrae (platyspondyly) and a rare chest wall malformation called a sternal cleft. Kidneys Two living individuals have been reported to have had underdeveloped and malformed kidneys. Although one was found to have normal kidneys on examination at birth, he later developed kidney failure in late adolescence and was found to have renal hypoplasia. Two siblings who did not survive to term had underdeveloped kidneys and ureters, leading to a build-up of urine called hydronephrosis. Blood One affected person was reported to have a reduced number of platelets (thrombocytopaenia) in infancy, requiring transfusion. Platelets are cellular fragments formed from protrusions on megakaryocytes that enable blood clotting. Blood symptoms have not yet been reported in any other affected individuals. Cause Strømme syndrome is caused by mutations in both copies of the CENPF