Deletions of different segments of the long arm of chromosome 4.

We report the clinical and chromosomal findings in 8 patients with deletions of the long arm of chromosome 4. Four of these patients appear to have terminal deletions beginning in band 4q31, and therefore, lack the digital 1/3 of the long arm of chromosome 4. We confirm that deletion of 4q31 leads to qter causes a recognizable syndrome, and we further define the phenotype of that syndrome. A 5th patient has a horter terminal deletion, ie, 4q33 leads to qter. This deletion causes a milder phenotypic expression than that seen in the severe 4q terminal-deletion syndrome. The remaining 3 patients have interstitial deletions of the long arm of the 4th chromosome, including segments 4q21.1 leads to q25, 4q21.3 leads to q26, and 4q27 leads to q31.3. The phenotypic expression noted in these patients is variable in differs from the 4q terminal-deletion syndrome.