Cytogenetic studies of individuals from four kindreds with multiple endocrine neoplasia type II syndrome

Abstract

Multiple endocrine neoplasia type II (MEN-II) syndrome is an autosomal dominant condition characterized by medullary carcinoma of the thyroid, pheochromocytoma, and parathyroid adenoma. A cytogenetic investigation was conducted on 13 MEN-II syndrome patients from four unrelated kindreds and 13 age-matched control subjects for chromosome instability and the chromosome 20 deletion reported in MEN-II syndrome. A significant increase (p < 0.05) was found in the total number of chromatid and chromosome aberrations in MEN-II cells (12.3%) compared with control cells (6.9%) grown at 96 hours in mitomycin C (20 ng/ml, final concentration). The major difference between the two groups was in chromatid, and not chromosome, aberrations. There was no difference between MEN-II and control individuals in fragile site expression, the number of sister chromatid exchanges or cell kinetics.A blind analysis of high-resolution G-banded chromosomes was performed on blood specimens from 13 MEN-II and seven control individuals. Twelve of 13 MEN-II patients and one of seven control subjects were scored as having a 20p12.2 deletion (χ 2 = 12.6; p< 0.001). Additional research is needed to determine if this cytogenetic finding is due to a chromosome deletion, inversion, or polymorphism.

Effects of age, sex and multiple endocrine neoplasia type-II on silver stained nucleolar organizer regions

“…Silver stain visualizes active nucleolar organizer regions (AgNORs) on the short arms of the five pairs of acrocentric chromosomes in man [1][2][3], Previous studies indicated that there are variations in the size and number of AgNORs between sexes, individuals at different ages and with various disorders including malignancies [4][5][6][7]. The purpose of our cytogenetic investigation was thus to examine AgNORs in cells of a relatively large number of normal individuals of both sexes at various ages as well as patients with multiple endocrine neoplasia-type II (MEN-II), an autosomal dominant malignancy syndrome with increased chromosome breakage characterized by medullary thyroid carcinomas, pheochromocytomas and parathyroid adenomas [8][9][10]. Therefore, we report for the first time AgNOR studies of lymphocytes from normal fetuses and patients with MEN-II and their comparison with control individuals at various ages.…”

Chromosome breakage and sister chromatid exchange analysis in computer operators

“…Peripheral blood (0.5 ml) was added to 10 ml of RPMI 1640 supplemented with 15% fetal calf serum, penicillin (20 U/ml), streptomycin (20 ug/ml), phytohemagglutinin, and 20 and/or 50 ng/ml mitomycin C (MMC) as previously described. 3,4,5 The cultures were incubated at 37° C for either 48 or 96 hours. Forty-five minutes before harvest, colcemid (0.2 ug/ml-final concentration) was added.…”