Radiological abnormalities associated with anomalies of the ninth chromosome.

The clinical and radiological features of Trisomy of the short arm of the ninth chromosome and of the Nail Patella Syndrome, both of which conditions are related to abnormalities of the ninth chromosome, are compared. Dislocation of the head of radius is seen in both conditions, as is a diminished patello condylar ratio. Several of the features described as being sporadic anomalies in the Nail Patella Syndrome are also seen in some patients with Trisomy of the Ninth Chromosome. The Trisomy 9 group also have several anomalies which are shared with Trisomy 21, Trisomy 17/18, Trisomy 13/15 and Trisomy 4, suggesting that some of these changes are a non-specific result of chromosome abnormality rather than being specific to the Trisomy 9.