Summary
Data on karyotype and maternal age of 1954 cases of Down's syndrome were analyzed to see if the rate of chromosome mutations leading to this abnormality has been enhanced during the last 20 years. Comparison of the data for patients born in 1947–1960 with those in 1961–1975 revealed little change with time in the proportions of cases due to different karyotypes, the overwhelming majority being of 21 trisomy type in both periods. However, there has been a remarkable decline in the mean maternal age from 33.1 years to 29.7 years as well as in the variance from 50.5 to 29.4. While the rate of decline in the variance was almost the same as that for all births occurring in the same periods, the decline in the mean maternal age was much greater for the patients than for all births, suggesting that the rate of nondisjunction might have increased in younger rather than in older mothers. However, when the risk of brearing a child with Down's syndrome for mothers aged 40–44 is taken as unity, no evidence was found for an increase with time in the relative risk for younger mothers. Moreover, results of surveys made in 1960 and thereafter in different parts of Japan indicate that the crude incidence rate of Down's syndrome at birth has been around 0.10%, giving no indication of an upward trend. These findings are discussed with reference to the serious environmental pollution, including possible genetic hazards, with which Japan has been faced since the 1960s.
Similar content being viewed by others
References
Gardner, R. J. M., Veale, A. M. O., Parslow, M. I., Becroft, D. M. O., Shaw, R. L., Fitzgerald, P. H., Hutchings, H. E., McCreanor, H. R., Wong, J., Eiby, J. R., Howarth, D. A., Whyte, S. E.: A survey of 972 cytogenetically examined cases of Down's syndrome. N. Z. Med. J. 78, 403–409 (1973)
Higurashi, M., Iijima, K., Kitamura, K., Karasawa, S., Hoshina, H., Watanabe, N., Ohkawa, Y.: Chromosome studies on 7158 newborn infants in Japan. Jap. J. Hum. Genet. 20, 247–248 (1976)
Kada, T.: Escherichia coli mutagenicity of furylfuramide. Jap. J. Genet. 48, 301–305 (1973)
Kondo, S., Ichikawa-Ryo, H.: Testing and classification of mutagenicity of furylfuramide in Escherichia coli. Jap. J. Genet. 48, 295–300 (1973)
Kuroki, Y., Yamamoto, Y., Matsui, I., Kurita, T.: Shift of child-birth to younger mothers, and its effect on the incidence of Down's syndrome in Japan, 1950–1973. Clin. Genet. (in press, 1977)
Lindsjö, A.: Down's syndrome in Sweden. An epidemiological study of a three-year material. Acta paediat. scand. 63, 571–576 (1974)
Lowry, R. B., Jones, D. C., Renwick, D. H. G., Trimble, B. K.: Down syndrome in British Columbia, 1952–1973: incidence and mean maternal age. Teratology 14, 29–34 (1976)
Matsunaga, E.: Possible genetic consequences of family planning. J. Amer. med. Ass. 198, 533–540 (1966)
Matsunaga, E.: Parental age, live-birth order, and pregnancy-free interval in Down's syndrome in Japan. In: Mongolism. G. E. W. Wolstenholme, R. Poter, eds., pp. 6–22. London: Ciba Foundation Study Group No. 25, Churchill 1967
Mikkelsen, M., Fischer, G., Stene, J., Stene, E., Petersen, E.: Unchanged incidence of Down's syndrome in Copenhagen from 1960 to 1971. V Intern. Cong. Human Genet. Intern. Congress Ser. No. 397, 141, Excerpta Medica (1976)
Murakami, A.: Problems in the pills (in Japanese). San Fujinka no Sekai 27, 843–849 (1975)
Ozawa, A., Yamada, K., Tonomura, A.: A survey on the incidence of Down's syndrome among newborn. Jap. J. Hum. Genet. 13, 161–162 (1968) (in Japanese)
Penrose, L. S.: The effect of change in maternal age distribution upon the incidence of mongolism. J. ment. Defic. Res. 11, 54–57 (1967)
Penrose, L. S., Smith, G. F.: Down's Anomaly. London: Churchill 1966
Shiono, H., Kadowaki, J., Nakao, T.: Maternal age and Down's syndrome. The shift of affected infants to younger mothers in Hokkaido. Clin. Pediatr. 14, 241–244 (1975)
Slavin, R. E., Kamada, N., Hamilton, H. B.: A cytogenetic study of Down's syndrome in Hiroshima and Nagasaki. Jap. J. Hum. Genet. 12, 17–28 (1967)
Tanaka, R.: Occurrence and distribution of Down's syndrome in a local area (in Japanese). Saishin Igaku 24, 318–322 (1969)
Tonomura, A., Oishi, H., Matsunaga, E., Kurita, T.: Down's syndrome: a cytogenetic and statistical survey of 127 Japanese patients. Jap. J. Hum. Genet. 11, 1–16 (1966)
Tonomura, A., Sasaki, M. S.: Chromosome aberrations and DNA repair synthesis in cultured human cells exposed to nitrofurans. Jap. J. Genet. 48, 291–294 (1973)
Tsubakihara, C.: Studies on mongolism (in Japanese). Acta paediat. jap. 64, 761–768; 2137–2141 (1960)
Vogel, F.: Wie stark ist die theoretische Häufigkeit von Trisomie-Syndromen durch Verschie-bungen im Altersaufbau der Mütter zurückgezogen? Zool. Beiträge 13, 451–462 (1967)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Matsunaga, E., Fujita, H. A survey on maternal age and karyotype in Down's syndrome in Japan, 1947–1975. Hum Genet 37, 221–230 (1977). https://doi.org/10.1007/BF00393585
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00393585