Partial monosomy of long arm of chromosome 4 due to interstitial deletion.

A child with congenital malformations and a de novo interstitial deletion of the long arm of chromosome 4 is described. Detailed analysis by G banding revealed the loss of the whole of band q21 and part of bands q13 and q22. The clinical abnormalities are quite dissimilar from those features described in other cases of partial 4q monosomy, which generally appear to result from the deletion of more distally placed segments of the chromosome.