Quantitative study of a proposed interstitial del (20p 12.2) in multiple endocrine neoplasia (MEN-II).

A quantitative measurement of the prophase Giemsa banding patterns in chromosome 20 of the peripheral blood samples obtained from seven patients with medullary carcinoma of the thyroid (MCT), three nonsymptomatic family members of MCT patients, and three normal controls has revealed no differences in the short arms of the two homologs. More specifically, measurements of band from 20p 12.1 to 20p 12.3 and statistical analysis of the mean ratio between these bands have given no indication of intersitial deletion in chromosome 20p of MCT patients.