Skip to main content
NCBI home page
American Journal of Human Genetics logoLink to American Journal of Human Genetics
. 1989 Sep;45(3):388–400.

Comparing observed average numbers of affected sibs with those expected under geometric ascertainment bias in an extended range in both simplex and multiple sibships.

K H Sit 1
PMCID: PMC1683409  PMID: 2788997

Abstract

Detection bias in recessive ascertainment is generally considered to be confined in a narrow range between unbiased truncate ascertainment and single ascertainment, where methods of segregation analysis are established. While there are arguments for an extended range of analysis, a deflated detection progression below the unbiased level is still being considered as theoretical ground or ignored as sporadics. I show here a method of gauging the ascertainment levels of surveyed data in a geometric continuum. The method is valid for recessive segregation at any ascertainment level and in simplex or multiplex sibships of whatever degree of truncation. Four previously published surveys are used to show conformation with real data and the existence of detection trends spanning the range from the unsuspected very depressed bias level to the inflated level above single ascertainment.

Full text

PDF
388

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. DEWEY W. J., BARRAI I., MORTON N. E., MI M. P. RECESSIVE GENES IN SEVERE MENTAL DEFECT. Am J Hum Genet. 1965 May;17:237–256. [PMC free article] [PubMed] [Google Scholar]
  2. Elandt-Johnson R. C. Segregation analysis for complex modes of inheritance. Am J Hum Genet. 1970 Mar;22(2):129–144. [PMC free article] [PubMed] [Google Scholar]
  3. Ewens W. J., Shute N. C. The limits of ascertainment. Ann Hum Genet. 1986 Oct;50(Pt 4):399–402. doi: 10.1111/j.1469-1809.1986.tb01760.x. [DOI] [PubMed] [Google Scholar]
  4. Henseler T., Christophers E. Psoriasis of early and late onset: characterization of two types of psoriasis vulgaris. J Am Acad Dermatol. 1985 Sep;13(3):450–456. doi: 10.1016/s0190-9622(85)70188-0. [DOI] [PubMed] [Google Scholar]
  5. Iselius L., Williams W. R. The mode of inheritance of psoriasis: evidence for a major gene as well as a multifactorial component and its implication for genetic counselling. Hum Genet. 1984;68(1):73–76. doi: 10.1007/BF00293877. [DOI] [PubMed] [Google Scholar]
  6. Li C. C. A method of subdividing genetic data into self-contained subsets. Ann Hum Genet. 1986 Jul;50(Pt 3):259–270. doi: 10.1111/j.1469-1809.1986.tb01047.x. [DOI] [PubMed] [Google Scholar]
  7. Li C. C., Mantel N. A simple method of estimating the segregation ratio under complete ascertainment. Am J Hum Genet. 1968 Jan;20(1):61–81. [PMC free article] [PubMed] [Google Scholar]
  8. MCKUSICK V. A., EGELAND J. A., ELDRIDGE R., KRUSEN D. E. DWARFISM IN THE AMISH I. THE ELLIS-VAN CREVELD SYNDROME. Bull Johns Hopkins Hosp. 1964 Oct;115:306–336. [PubMed] [Google Scholar]
  9. Morton N. E., Mi M. P. Multiplex families with two or more probands. Am J Hum Genet. 1968 Jul;20(4):361–367. [PMC free article] [PubMed] [Google Scholar]
  10. SMITH C. A. A note on the effects of method of ascertainment on segregation ratios. Ann Hum Genet. 1959 Jul;23:311–323. doi: 10.1111/j.1469-1809.1959.tb01474.x. [DOI] [PubMed] [Google Scholar]
  11. STEINBERG A. G., BECKER S. W., Jr, FITZPATRICK T. B., KIERLAND R. R. A genetic and statistical study of psoriasis. Am J Hum Genet. 1951 Sep;3(3):267–281. [PMC free article] [PubMed] [Google Scholar]
  12. STEVENSON A. C., CHEESEMAN E. A. Heredity and rheumatic fever; a study of 462 families ascertained by an affected child and 51 families ascertained by an affected mother. Ann Eugen. 1953 Feb;17(3):177–210. doi: 10.1111/j.1469-1809.1953.tb02546.x. [DOI] [PubMed] [Google Scholar]

Articles from American Journal of Human Genetics are provided here courtesy of American Society of Human Genetics

RESOURCES