Abstract. X-chromatin body (XCB) frequencies in oral mucosa were investigated in 14 female patients with the simple non-salt-losing form of congenital virilizing adrenal hyperplasia (CVAH) due to 'partial' 21-hydroxylase deficiency (CVAH-type I), using toluidine blue (TBS) and Feulgen's stains (FS).
They were found to be lower than normal controls by both TBS (12.6 ± 1.73 vs 18.38 ± 0.41) and FS (13.60 ± 2.16 vs 17.94 ± 0.76) methods. After 4–5 weeks on glucocorticoid therapy, XCB frequencies overlapped with those of normal controls using both TBS (16.54 ± 1.76) and FS (17.09 ± 1.98). Karyotypes performed in 8 of the 14 cases showed a normal female pattern.
Two possible interpretations are proposed: First, variations of XCB counts may reflect the average nuclear size of the cell populations studied. Second, high androgen levels found in untreated cases with CVAH-type I might lead to partial chromosome depiralization and increasing euchromatic areas. At present the first possibility appears more likely.