Radioulnar Synostosis

Watchlist

(log in to enable)

Retrieved

2019-09-22

Source

Omim

Trials

—

Genes

TBX22, SMAD6, SALL4, MECOM, B4GALT7, COLEC10, KAT6B, MRAS, CPLX1, APC, SETBP1, SF3B4, GTF2IRD1, CHST3, SMC3, BAZ1B, SMC1A, NIPBL, DONSON, B3GAT3, TBL2, NSD2, FGFRL1, BCOR, SETD5, HDAC8, PIEZO2, XYLT1, COLEC11, CANT1, A2ML1, ESCO2, LZTR1, WHCR, BRAF, CLIP2, CTBP1, DHODH, ELN, FGFR2, GTF2I, HOXA11, KRAS, LETM1, LIMK1, LRP4, MAF, KMT2A, NRAS, POR, MASP1, PTPN11, RAD21, RAF1, RASA2, RFC2, RIT1, RPL26, RRAS, SOS1, SOS2, TBX5, TWIST1, EFTUD2, NOG, CCR7, FMN1

Drugs

—

Interested in hearing about new therapies?

There are 2 types of radioulnar synostosis: in type 1, there is a proximal, smooth fusion of 2-6 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.

Rizzo et al. (1997) reported 2 sporadic and 5 familial cases of autosomal dominant radioulnar synostosis type 1. One of the sporadic cases was unilateral; the other was bilateral and associated with minor anomalies including decreased anteroposterior diameter of the thorax and borderline intelligence. The 5 familial cases in 3 generations were bilateral and had a Dubois sign (tip of 5th finger is proximal to the DIP joint of the 4th digit), relative hypoplasia of the lateral metacarpals, and shortness of all phalanges of the 5th fingers. The findings suggested involvement of an ulnar developmental field.

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).

James et al. (1995) found a mosaic karyotype 46,XY/47,XYY/48,XYYY in a 3-year-old boy with bilateral radioulnar synostosis. Townes et al. (1965) and Mazauric-Stuker et al. (1992) reported radioulnar synostosis in cases of nonmosaic 48,XYYY karyotype. Turner et al. (1963) and Das et al. (1993) reported it in males with additional X chromosomes.

Thompson and Nguyen (2000) found that autosomal dominant radioulnar synostosis with amegakaryocytic thrombocytopenia (605432) was caused by mutation in the HOXA11 gene (142958) in 2 pedigrees. Not all of the affected family members had amegakaryocytic thrombocytopenia.