European Journal of Pediatrics

, Volume 124, Issue 4, pp 231–256 | Cite as

A biologic and genetic study of 40 cases of severe pure mental retardation

  • J. M. Becker
  • E. G. Kaveggia
  • E. Pendleton
  • J. M. Opitz


The family history of 40 patients with severe “pure” mental retardation (MR) was studied to determine the incidence of mental retardation and dull-normal intelligence among relatives, probable etiologies and an empriric recurrence risk. Significant findings include: (1) an increased sex ratio (69% males) of propositi, (2) a significant proportion of patients with clinical manifestations besides MR, (3) virtually no consanguinity among parents, (4) a “positive” family history for over 1/2 of the propositi—about 37% of all children in the sibships were affected; about 21% of the full sibs were affected, (5) a higher number of offspring produced by dull persons and a lower number of offspring from retarded persons compared to two normal persons, (6) a proportionately large number of affected children produced from matings involving one or two dull persons, (7) a tendency for dull persons to have additional dull children and mentally retarded parents to have further retarded children while normal parents with more than one affected child usually had further retarded children, (8) an incidence of affected parents of about 32%, and (9) an overall empiric recurrence risk of 14%.

Several etiologies were discussed as possible causes of the condition(s) in this group: (unrecognized) environmental damage and/or maternal/fetal interaction; unrecognized chromosome abnormalities; the homozygous state of several different autosomal recessive genes; X-linked recessive mutations; autosomal dominant new mutations; and multifactorial inheritance. It was concluded that the group was etiologically heterogeneous and although none of the probable etiologies could be excluded, it seemed reasonable to assume that autosomal recessive inheritance plays an important role in the etiology of severe “pure” mental retardation.

Key words

Severe mental retardation Etiology Family history Recurrence risk Autosomal recessive 


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  1. Åkesson, H. O.: Severe mental deficiency in Sweden. Göteborg: Elanders Boktryckeri AB 1968Google Scholar
  2. Angeli, E., Kirman, B.: Genetic prognosis in severe mental handicap. J. Ment. Defic. Res. 19, 173–193 (1975)Google Scholar
  3. Berg, J. M., Kirman, B. H.: Some aetiological problems in mental deficiency. Br. Med. J. 2, 848–852 (1959)Google Scholar
  4. Bundey, S., Carter, C. O.: Recurrence risks in severe undiagnosed mental deficiency. J. Ment. Defic. Res. 118, 115–134 (1974)Google Scholar
  5. Dewey, W. J., Barrai, I., Morton, N. E., Mi, M. P.: Recessive genes in severe mental defect. Am. J. Hum. Genet. 17, 237–256 (1965)Google Scholar
  6. Hallgren, B., Sjögren, T.: A clinical and genetico-statistical study of schizophrenia and low-grade mental deficiency in a large Swedish rural population. Acta Psychiatr. et Neurol. Scand. Supplementum 140, 1–65 (1959)Google Scholar
  7. Halperin, S. L.: A clinico-genetical study of mental defect. Am. J. Ment. Defic. 50, 8–26 (1945)Google Scholar
  8. Heber, R.: A manual on terminology and classification in mental retardation. Am. J. Ment. Defic. Monograph Supplement (1961)Google Scholar
  9. Kaveggia, E. G., Durkin, M. V., Pendleton, E. Opitz, J. M.: Diagnostic/genetic studies on 1224 patients with severe mental retardation. In: Proc. 3rd. Int. Congr. IASSMD, pp. 82–93. Warsaw: Polish Medical Publishers 1975Google Scholar
  10. Kaveggia E. G., Opitz, J. M., Pallister, P. D.: Diagnositic/genetic studies in severe mental retardation. In: Proc. 2nd Int. Congr. IASSMD, pp. 305–311 Warsaw: Polish Medical Publishers 1971Google Scholar
  11. Laxova, R., Ridler, M. A. C., Bowen-Bravery, M.: An aetiological survey of severely subnormal children born between 1st January 1965 and 31st December 1967 living in Hertfordshire. In press (1976)Google Scholar
  12. Lehrke, R. G.: X-linked mental retardation and verbal disability. Birth Defects Original Article Series X/1 (1974)Google Scholar
  13. Opitz, J. M., Kaveggia, E. G., Pallister, P. D.: Studies of genetic malformation/retardation syndromes. In: Proc. 2nd Int. Congr. IASSMD, pp. 115–119. Warsaw: Polish Medical Publishers 1971Google Scholar
  14. Opitz, J. M.: Diagnostic/genetic studies in severe mental retardation. Presented at the NICHD Genetic Counseling meeting, Colorado Springs, H. A. Lubs, editor. In press 1976Google Scholar
  15. Pallister, P. D., Kaveggia, E. G., Inhorn, S. L., Meisner, L., Opitz, J. M.: Chromosome studies in malformation/retardation syndromes. In: Proc. 2nd Int. Congr. IASSMD, pp. 313–322. Warsaw: Polish Medical Publishers 1971Google Scholar
  16. Penrose, L. S.: A clinical and genetic study of 1280 cases of mental defect. Med. Res. Coun.: Spec. Rep. Number 229, London: H. M. Stationary Office 1938Google Scholar
  17. Penrose, L. S.: The Biology of Mental Defect. 3rd. ed. London: Sidgwick and Jackson, Ltd. 1963Google Scholar
  18. Pitt D., Roboz, P.: A survey of 782 cases of mental deficiency. J. Ment. Defic. Res. 9, 4–23 (1965)Google Scholar
  19. Reed, E. W., Reed, S. C.: Mental Retardation: A Family Study. Philadelphia: W. B. Saunders Company 1965Google Scholar
  20. Roberts, J. A. F.: The genetics of mental deficiency. Eug. Rev. 44, 71–83 (1952)Google Scholar
  21. Turner, G., Collins, E., Turner, B.: Recurrence risk of mental retardation in sibs. Med. J. Aust. 1, 1165–1166 (1971)Google Scholar

Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • J. M. Becker
    • 1
  • E. G. Kaveggia
    • 3
  • E. Pendleton
    • 3
  • J. M. Opitz
    • 1
    • 2
  1. 1.The Wisconsin Clinical Genetics Center of the Department of Medical GeneticsUniversity of WisconsinMadisonUSA
  2. 2.the Department of Pediatrics of the Center for Health Sciences and Medical SchoolUniversity of WisconsinMadisonUSA
  3. 3.Central Wisconsin Colony and Training SchoolMadisonUSA

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