Trisomy 18q-. Trisomy mapping of chromosome 18 revisited

Two patients with trisomy for 18p and the proximal segment of 18q (trisomy 18q –) are reported and compared with similar cases from the literature. The phenotype of trisomy 18q– resembles that of full trisomy 18 but differs mainly in the birdlike face, small mouth, more pronounced microretrognathia, minor skeletal dysplasia and inner organ malformations, and less severe vital prognosis.