A simple method for high-resolution banding of chromosomes and its application to diagnosis of birth defects

A simple method for obtaining high-resolution banding patterns on elongated chromosomes is devised as follows: Peripheral lymphocytes cultured for 3 days with phytohemagglutinin were exposed to 10 micrograms/ml ethidium bromide for 2 hours and with 0.02 micrograms/ml colcemid for 1 hour prior to harvesting. After preparation by steam-dry method, high-resolution G-bands were obtained by Giemsa staining following exposure to hydrogen peroxide and trypsin treatment. 19 cases of the Prader-Willi syndrome, 3 cases of the aniridia-Wilms' tumor syndrome, 2 cases of the Langer-Giedion syndrome, 2 cases of retinoblastoma and 6 cases with multiple congenital anomalies whose diagnosis was not made by routine chromosome analysis were examined by this method. 18 of the 19 cases of the Prader-Willi syndrome had a deletion of 15q11.2. 2 of the 3 cases of the aniridia-Wilms' tumor syndrome had a deletion of 11p13 and the other had a balanced insertion with a breakpoint at 11p13. The 2 cases of the Langer-Giedion syndrome had a deletion of 8q23.3-24.13. One of retinoblastoma had a deletion of 13q14 and the other had a balanced reciprocal X/13 translocation with breakpoints at Xp11.21 and 13q12.3. The last 6 cases had subtle chromosomal aberrations: 46, XX, del (5) (q15q22), 46, XX, del (13) (q32.3), 46, XX, inv dup (6) (p25p21.3), 46, XX, -5, +der (5), t (3; 5) (p23; p13) mat, 46, XX, -5, +der (5), t (5; 9) (p13.3p21) mat, and 46, XX, -4, +der (4), t (4; 16) (p15.2; p13.1) pat. The simple method for high-resolution banding of chromosomes is useful for diagnosis of many kinds of birth defects.