August 1981

Ring 4 Chromosome With Terminal p and q Deletions

Author Affiliations

From the Laboratory of Medical Genetics, University of Alabama in Birmingham (Drs W. Finley and S. Finley and Mr Chandler); and the Lloyd Noland Hospital, Fairfield, Ala (Dr Chonmaitree). Dr Koors is in private practice in Troy, Ala. Dr Chonmaitree is now with the University of Rochester, NY.

Am J Dis Child. 1981;135(8):729-731. doi:10.1001/archpedi.1981.02130320043015

• A ring 4 chromosome was found in a boy with low birth weight, microcephaly, micrognathia, rounded broad nose, malformed ears, cleft soft palate, and retardation in growth and development. The ring 4 is formed by union of the ends after breakage and loss of the terminal parts of the short (p) arm and the long (q) arm. G-banded chromosome studies showed our patient to have a union at p16q35. Clinical findings in our patient were compared with those in others with the union at p16q35, p15q35, and p16q33. The patients with p15q35 had a deletion of more p-arm genetic material than those with the p16q35 union, and the patient with p16q33 had a greater loss of q-arm material. The loss of only a small part of the p16 band is associated with low birth weight, microcephaly, and retardation in growth and development.

(Am J Dis Child 1981;135:729-731)