MedGen

There are 2 types of radioulnar synostosis: in type 1, there is a proximal, smooth fusion of 2 to 6 cm between the radius and ulna and the radial head is absent; in type 2, there is a fusion just distal to the proximal radial epiphysis in association with congenital dislocation of the radial head (Bauer and Jonsson, 1988). Both types result in a limitation of pronation and supination of the forearm, and in type 2 there is also a restriction of extension at the elbow. Dominant inheritance through several lines in several generations was demonstrated by a family reported by Davenport et al. (1924). Hansen and Andersen (1970) found a positive family history in 5 of 37 cases. Radioulnar synostosis is a feature of certain chromosome abnormalities, notably the triple X-Y syndrome (XXXY). See pronation-supination of the forearm, impairment of (176800). Radioulnar synostosis occurs in an autosomal dominant syndrome with amegakaryocytic thrombocytopenia; see RUSAT1, 605432. [from OMIM]

Craniosynostosis is a primary abnormality of skull growth involving premature fusion of the cranial sutures such that the growth velocity of the skull often cannot match that of the developing brain. This produces skull deformity and, in some cases, raises intracranial pressure, which must be treated promptly to avoid permanent neurodevelopmental disability (summary by Fitzpatrick, 2013). For a discussion of genetic heterogeneity of craniosynostosis, see CRS1 (123100). [from OMIM]

Any aortic valve disease in which the cause of the disease is a mutation in the SMAD6 gene. [from MONDO]