Ritscher-schinzel (3c) syndrome: Documentation of the phenotype and its relationship to "Joubert syndrome with chorioretinal coloboma"

Ritscher-Schinzel syndrome or 3C (cranio-cerebello-cardiac) syndrome is characterized by cardiac defects, cerebellar vermis hypoplasia, and cranial detects. Although twelve cases previously have been reported, the full spectrum of this condition has not been determined. We have evaluated two unrelated males with this condition. Both had defects of the endocardial cushion and vermis hypoplasia with hypotonia. In addition both had hypospadias, a previously undescribed feature of this disorder. Review of the previously reported cases as well as those herein described reveal the following: 1) Although varying degrees of vermis hypoplasia are accompanied by hypotonia, delayed gross motorfunction improves with advancing age, leaving speech delay as the major neurodevelopmental handicap. 2) Two different types of cardiac anomalies occur: Defects of the endocardial cushion ranging from anomalies of the mitral or tricuspid valves to complete AV canal, and/or conotruncal defects (Tetralogy of Fallot and double outlet right ventricle). 3) Postnatal growth deficiency was seen in the majority of cases in whom longitudinal information was available. 4) Ritscher-Schinzel syndrome and "Joubert syndrome with bilateral chorioretinal coloboma (MIM 243910)," which is distinctive from "Joubert syndrome with retinal dysplasia (Dekaban syndrome, MIM 213300)," most likely represent the same disorder.